Creutzfeldt-Jakob disease, MRI scan.


Variant Creutzfeldt-Jakob disease (vCJD), high power microscopic.


Creutzfeldt-Jakob disease, high power microscopic.


Creutzfeldt-Jakob disease, medium power microscopic.


Amyotrophic lateral sclerosis, muscle biopsy, microscopic, trichrome stain.


Amyotrophic lateral sclerosis, microscopic, Luxol fast blue stain.


Amyotrophic lateral sclerosis. microscopic.


Amyotrophic lateral sclerosis, gross.


Lewy bodies, microscopic.


Parkinson disease, microscopic.


Parkinson disease, gross.


Huntington disease, microscopic.


Huntington disease, gross.


Multi-infarct dementia, gross.


Progressive supranuclear palsy, globose tangle, Bielschowsky stain, microscopic.


Pick disease, gross.


Diffuse Lewy body disease, microscopic.


Alzheimer disease, neurofibrillary tangle, with Bielschowsky silver stain, microscopic.


Alzheimer disease, neurofibrillary tangle, H and E stain, microscopic.


Alzheimer disease, senile plaque, with Congo red stain, microscopic.


Alzheimer disease, thioflavin stain, microscopic.


Alzheimer disease, Bielschowsky silver stain, microscopic.


Alzheimer disease, gross.


Ludwig Türck (1810-1868)


Part of the causal chain leading to  Alzheimer's disease


Deaths due to neurological conditions per million persons 2012     18-52    53-68    69-84    85-99    100-131    132-157    158-186    187-243    244-477    478-1,482


Some of the fields that contribute to understanding mental functioning


Table from the 2010  DrugScience  study ranking various drugs (legal and illegal) based on statements by drug-harm experts. This study rated alcohol the most harmful drug overall, and the only drug more  harmful to others  than to the users themselves. [ 4 ]


Acute confusional state caused by alcohol withdrawal, also known as  delirium tremens


Chromosome 15


Melatonin


"Boy with a Puppet" or "A child with a drawing", circa 1520, by  Giovanni Francesco Caroto ; the portrait motivated the initial naming of Angelman syndrome as  puppet syndrome . [ 45 ]


People with Asperger syndrome often display restricted or specialized interests, such as this boy's interest in stacking cans.


Functional magnetic resonance imaging  provides some evidence for mirror neuron theory. [ 79 ]


Students and families walk to support Autism Awareness Month.


The  trigeminal nerve .


The mythical Oedipus gouged his eyes out.


Different sections of semicircular canals.  utricle  and  saccule  are indicated by circles.


Basilar invagination in an infant with  Wolf–Hirschhorn syndrome .


Thyroid transcription factor associated with BHC


Motor cortex region involved in the learning retention


Left eye showing proptosis.


Visual field of homonymous hemianopia


Fluorescein angiography can reveal arteriovenous malformations.


A coup injury occurs under the site of impact with an object, and a contrecoup injury occurs on the side opposite the area that was hit.


Bromide rash


BVVL has autosomal recessive pattern of inheritance


Electroencephalogram (EEG) displaying burst suppression patterns. Onset of bursts are indicated by solid arrows; offset, by open arrows. In both A and B, the interval between each vertical dotted line is one second.


Patients with a high burst suppression ratio (yellow circles) show significantly better recovery from coma (traumatic etiologies) as measured by the Glasgow Outcome Scale extended (GOSe) 6 months post-injury (histogram on vertical axis). Figure from Frohlich et al. 2021 Frontiers in Neurology.


A clinical photograph showing a patient with the flexed posture. It can be abated when lying down. [ 1 ]


Alexandre-Achille Souques was one of the first major researchers of camptocormia and created the definition and name used for the condition to this day.


Spinal-muscle biopsy showing intense endomysial deposit of  fibrosis  (green) and fatty infiltration. Also observable is irregular distribution of involuted muscle fibers. (Trichrome, original magnification ×9100) [ 2 ]


Thymatron IV used for electroconvulsive therapy


Typical  deep brain stimulation  setup


Diplopia is a symptom that individuals with cerebellar degeneration may experience.


Diagram of two different nerve cells. The diagram on the left shows a nerve cell that is healthy and normally-functioning. The diagram on the right shows a nerve cell with a damaged myelin sheath, being the cause of multiple sclerosis.


Magnetic resonance imaging scans of two different brains. The scan of the brain on the left indicates a weakened, deteriorated cerebellum of a human with cerebellar degeneration. The scan of the brain on the right indicates a healthy, normally-functioning cerebellum of a human.


Coronal CT of the brain showing a choroidal fissure cyst


Structure of a typical neuron with  Schwann cells  in the  peripheral nervous system


Cockayne syndrome has an  autosomal recessive  pattern of  inheritance .


Johnny Head-in-Air is an absent-minded boy who seems unaware of his surroundings.


Animation of cortical spreading depression


Cortical spreading depression seen using intrinsic optical signal imaging in  gyrencephalic  brain. Speed 50x. [ 1 ]


Hemodynamic changes observed after  MCA  occlusion in IOS. The video has a speed of 50x to better appreciate the SDs through human eye. Pictures are dynamically subtracted to a reference picture 40 s before. First we see the initial area of change at the exact moment where the left MCAs are occluded. The area is highlighted with a white line. Later we appreciate the signal produced by SDs. [ 2 ]


Drawing by  Donald Ogden Stewart  published in 1921 showing Little Elmer's father with DTs and seeing pink elephants


Huyghe Brewery 's flagship beer is  Delirium Tremens , a golden ale.


Guillain–Barré syndrome – demyelination


Daniel Radcliffe, actor, has dyspraxia.


Weight loss from diencephalic syndrome


Punding , a possible symptom of DDS, is the repetition of complex motor behaviors such as collecting or arranging objects.


A slot machine, commonly used for gambling.


The dopamine transporter protein, pictured here, is mutated in DTDS patients.


Dysgraphia can be difficult to diagnose because the handwriting starts out clear and slowly degrades, making the writer appear lazy.


Figure 1.  Schematic structure of K V 1.1 with the episodic ataxia type 1 mutations noted in red.


Figure 2.  Schematic structure of Ca V 2.1 with the episodic ataxia type 2 mutations noted in red.


Kaiser   Wilhelm II  was affected by Erb's palsy in his left arm.


Some of the steps in the manufacture of felt hats are illustrated in this image from 1858.


A man working in hat manufacture with no protective equipment, putting him at risk for mercury poisoning


Picture postcard of a hat factory in Danbury (postmarked 1911)


While the name of Lewis Carroll's Mad Hatter may contain an  allusion  to the hatters' syndrome, the character itself appears to have been based on an eccentric furniture dealer.


Convulsive symptoms of ergotism


Claviceps purpurea  fungal  sclerotium  growing on barley


Ergot in  barley


Detail from the painting  Temptation of St Anthony  by  Matthias Grünewald , showing a patient with advanced ergotism


" Right hemisphere of the brain "


Figure from a paper by J. Driver and P. Vuilleumier explaining the effect of grouping on extinction reduction.


Facial characteristics of a child with FAS


A  label on alcoholic drinks  promoting zero alcohol during  pregnancy


Smooth philtrum seen on a six-month-old baby with FAS


Beer Street  and  Gin Lane , William Hogarth (1751)


Human lower leg anatomy


An AFO (ankle foot orthosis) brace is a type of orthotic used to support the foot and ankle.


Dynamic advanced orthosis for drop foot


Animation of the frontal lobe, shown in red


Animation of the cerebellum, shown in red


The M2 pathway is shown in red, originating in the pre-motor cortex. The PrL pathway is shown in purple, originating in the medial prefrontal cortex


Intermediate magnification  micrograph  showing giant cell arteritis in a  temporal artery  biopsy. The arterial lumen is seen on the left. A giant cell is seen on the right at the interface between the thickened  intima  and  media .   H&E stain


Histopathology of giant cell vasculitis in a cerebral artery. Elastica-stain.


Major Gulf War engagements in which DU rounds were used


Louis Jones Jr . claimed Gulf War syndrome as a defense in his murder trial


Lesions lips, patient with hemorrhagic hereditary telangiectasia.


Tongue telangiectases as seen in a person with hereditary hemorrhagic telangiectasia


A very large arteriovenous malformation in the left hemisphere (on the right in this image) of the brain.


Hereditary hemorrhagic telangiectasia has an autosomal dominant pattern of inheritance.


A schematic representation of the TGF-β signaling pathway. Endoglin (yellow) is needed for signalling. The ligand (blue) binds to the receptor complex; red indicates a type II receptor protein, which activates a type I receptor protein (turquoise) such as alk-1, which in turn phosphorylates a SMAD-based nuclear transcription factor (green and purple).


A vascular lesion in the digestive tract, being treated with argon plasma coagulation.


CT-scan of vascular malformations in the liver in a patient with hereditary hemorrhagic telangiectasia causing an inhomogeneous perfusion pattern.


The  Netherlands Antilles , where HHT is more common than anywhere in the world, located off the coast of Venezuela.


Foot showing features of HMSN:  pes cavus  and clawing of the toes


Myelinated neuron


Ankle foot orthosis


The  basal ganglia  are involved in hyperkinesia.


Samuel Alexander Kinnier Wilson , the neurologist most known for his description of what came to be known as  Wilson's disease .


A healthy, neuropathic, and myopathic electromyogram, respectively.


Scientifically accurate atomic model of the external structure of SARS-CoV-2. Each "ball" is an atom.


Structure of the olfactory epithelium. SARS-CoV-2 infects the support cells (sustentacular cells), which injures the olfactory neurons in the olfactory epithelium leading to loss of smell. New olfactory neurons regenerate from the basal cells.


Impact of COVID-19 on neurological and psychiatric outcomes in the subsequent 6 months compared with other respiratory tract infections [ 16 ]


The cerebellum is highlighted in purple.


A  radiography  during an intervention of  deep brain stimulation


Eukaryote cells sort misfolded proteins into two quality control compartments: JUNQ and IPOD, based on their ubiquitination state.


Eukaryote cells sort misfolded proteins, based on their ubiquitination state, into two quality control compartments:  1. JUNQ (green), which is tethered to the  nucleus  (orange) 2. IPOD(green), which is tethered to the  vacuole  (black shadow)


A JUNQ inclusion viewed by a ubiquitinated VHL protein(green), is tethered to the  nucleus  (orange).


An IPOD inclusion viewed by a non-ubiquitinated VHL protein(red), tethered to the  vacuole  (green).


' Graph 1'  Represents data that  shows how Lafora disease has been distributed throughout not just the United States but the world as a whole. This particular graph shows  250 families that have been affected by Lafora Disease. [ 19 ]


' Graph 2'  Represents data that shows how the gene mutation for both EPM2A and EPM2B has been distributed around the world. The data goes to show that there are more cases caused by EPM2B than there are for EPM2B (NHLRC1). [ 19 ]


Lafora disease has an  autosomal recessive  pattern of inheritance. [ 18 ]  EPM2A gene found on chromosome 6q24 and NHLRC1 gene found on chromosome 6p22.3. [ 20 ]


Gonzalo Rodríguez Lafora , discoverer of the disease


Two healthy mitochondria from mammalian lung tissue as shown by electron microscopy


The autosomal recessive pattern of inheritance seen in some cases of Leigh syndrome


The  X-linked recessive  pattern of inheritance seen occasionally in cases of Leigh syndrome


Chemical structure of methylprednisolone. Corticosteroids are used during acute multiple sclerosis relapses.


Disease-modifying treatments are expensive and most require frequent (up-to-daily) injections, under the skin or into the muscle. Newer treatments feature intravenous (IV) infusions (shown above) at 1 to 3-month intervals.


Injectable medications can produce irritation or bruises at injection site. The bruise depicted was produced by a subcutaneous injection.


Irritation zone after injection of glatiramer acetate.


Chemical structure of mitoxantrone


Supervised physical therapy may be helpful to overcome some symptoms.


Chemical structure of  alemtuzumab


Lateral cutaneous nerve of thigh  and other structures passing between the left inguinal ligament and ilium, frontolateral view of the right side of the pelvis.


Mevalonic acid


The biosynthesis of isoprenoids


Mevalonate pathway


Mevalonate kinase deficiency has an autosomal recessive pattern of  inheritance .


Amsler grid as it might appear to someone with micropsia as a result of  age-related macular degeneration .


An  MRI  image of a brain tumor occupying the left  temporal  and  parieto - occipital  regions of the brain.


Chilean writer Ana María Haebig has Moebius Syndrome


Sagittal  magnetic resonance imaging  scan showing a markedly underdeveloped ( hypoplastic ) tongue


Mentally disabled woman with features indicative of Muenke syndrome


Muenke Syndrome is inherited in an  autosomal dominant  pattern.


Typical time frames of post-exertional malaise after normal daily activities


Results of a study on the  quality of life  of individuals with ME/CFS, showing it to be lower than in 20 other chronic conditions


When people with ME/CFS exercise on consecutive days, their performance declines on the second day, unlike those with  unexplained chronic fatigue  (ICF).


Could You Have ME/CFS?  handout from the US Centers for Disease Control and Prevention


A heart rate monitor can be helpful for energy management.


Incidence rates by age and sex, from a 2014 study in Norway


Presentation of a petition to the  National Assembly for Wales  relating to ME support in South East Wales


The blue ribbon is used for ME/CFS awareness.


Graph of ME/CFS papers published by year:    Papers mentioning ME or CFS    Papers whose title mentions ME/CFS


According to a 1922  osteopath , the  Venus de Milo  was "neurasthenic as her stomach was not in the proper position". [ 13 ]


Comparison of brain tissue between healthy individual and Alzheimer's disease patient, demonstrating extent of neuronal death


Risks from viral exposures according to one biobank study [ 58 ]


A child with  Down syndrome


CT scan  showing  epidural hematoma , a type of traumatic brain injury (upper left)


MRI


Map of England


Café au lait spot  characteristic of NF1


Diagnostic criteria of neurofibromatosis type I, requiring at least 2 of the mentioned items. [ 6 ]


MRI image showing malignant peripheral nerve sheath tumor in the left tibia in neurofibromatosis type-1


NF-1 is inherited in an  autosomal dominant  fashion, although it can also arise due to spontaneous mutation.


NF-2 may be inherited in an  autosomal dominant  fashion, as well as through random mutation.


Micrograph  of a  schwannoma , a tumor seen in neurofibromatosis type II.  HPS stain .


Schwannoma of the N. Vestibularis


Meningiomas in a person with NFII


NF-2 Locus


Left image :  MRI  findings (T1-weighted images) in a patient with neurosacoidosis showing thickening of  infundibulum  and both  optic nerves  (white signal marked with yellow arrows; width 6 mm).   Right image : MRI brain with contrast showing near resolution of enhancement after treatment.


Nystagmus as seen in a case of  ocular albinism


Fast-phase horizontal eye movement vision


Fast-phase vertical eye movement vision


A diagram of the  caloric reflex test , which tests the  vestibulo-ocular reflex  (VOR) by irrigating the ear canal with warm or cold water to induce physiological nystagmus.


MRIs of a normal individual (left) and a patient with microcephaly caused by genetic mutation (right)


Electroencephalogram (EEG) displaying burst suppression patterns. Onset of bursts are indicated by solid arrows; offset, by open arrows. In both A and B, the interval between each vertical dotted line is one second


Figure 2: This image shows the three different types of aortic dissection.


Figure 3: A visualization of the aorta (4) in relation to the pulmonary artery (5).


The eponymous objects


Site of speech processes that sit on the Perisylvian Fissure


Man with facial paralysis on his right side


Image of arachnoid cyst


CT scan with MCA infarction


image of cerebral angiography


Middle cranial fossa


Image of brain MRI.


Friedrich Albert von Zenker


A mirror box used for treating phantom limbs, developed by V.S. Ramachandran


Structure of Venlafaxine


Misfolded proteins can form protein aggregates or  amyloid fibrils , get  degraded , or refold back to its  native structure .


Micrograph of amyloid in a section of  liver  that has been stained with the dye Congo red and viewed with crossed polarizing filters, yielding a typical orange-greenish birefringence. 20X microscope objective; the scale bar is 100 microns (0.1mm).


Micrograph of immunostained  α-synuclein  (brown) in  Lewy bodies  (large clumps) and Lewy neurites (thread-like structures) in the cerebral cortex of a patient with  Lewy body disease , a  synucleinopathy . 40X microscope objective.


Progressive neuropathy can lead to irreversible damage, early identification of asymptomatic neuropathy may prevent loss of limb.


Animals with "dumb" rabies appear depressed, lethargic, and uncoordinated


A young girl about to receive PEP after being bitten by an animal thought to be rabid


Map of rabies-free countries and territories


Rabies cases in humans and domestic animals – United States, 1938–2018


Two dogs with the paralytic, or dumb, form of rabies


Diagram illustrating the locations of extraocular muscles and ocular cranial nerves. Paresis of the oculomotor nerve (CNIII) reduces the strength of  medial rectus ,  superior rectus ,  inferior rectus , and  inferior oblique  muscles, while trochlear nerve (CNIV) and abducens nerve (CNVI) paralysis affect  superior oblique muscle  and  lateral rectus muscle  respectively.


Physical examination showing ophthalmoplegia affecting the left eye. The central image represents forward gaze while other images represents different direction of gaze. Drooping of eyelids  (ptosis ) and nonaligned eyes ( strabismus ) are observed, showing paresis of CNIII, CNIV and CNVI.


Artist's depiction of a scintillating scotoma, exhibiting a flashing visual pattern similar to  dazzle camouflage  used during WWI.


An artist's depiction of a scintillating scotoma with a bilateral arc


In teichopsia, migraine sufferers see patterns in the shape of the walls of a  star fort .


The vestibular system is stimulated through hanging equipment such as tire swings.


Human body temperature scale, showing the body temperature of what is considered hypothermia.


Hyperhidrosis


Location of the corpus callosum within the human brain.


Coronal sections of human brain labeling the basal ganglia.


Target molecules of botulinum (BoNT) and tetanus (TeNT) toxins inside the axon terminal. [1]


Insertion of electrode during surgery


Motor track


Baclofen


Doppler ultrasound of subclavian steal phenomenon


Angiogram of subclavian steal phenomenon before and after stent placement


CT angiography of subclavian steal phenomenon


Erythema marginatum


Penicillin


Lifecycle of  T. solium . Red arrows indicate pig; blue arrows human.


MRI sagittal image of sacral and dorso-lumbar perineural cysts.


Timothy syndrome has an autosomal-dominant pattern of inheritance.


Syndactyly  in a  2 + 1 / 2  -year old girl with Timothy syndrome


A reconstruction of the vertebral arteries from a CT scan, seen from the front. From the bottom, V1 is from the subclavian artery to the foramina, V2 is from the foramina to the second vertebra, V3 is between the foramina until entry into the skull, and V4 is inside the skull embedded in the  dura mater . They merge into the basilar artery, which then divides into the  posterior cerebral artery .


Magnetic resonance angiogram of the neck vessels in a person with Ehlers-Danlos syndrome type IV; it shows a dissection of the left internal carotid artery, dissection of both vertebral arteries in their V1 and V2 segments and a dissection of the middle and distal third of the right subclavian artery. Such striking episodes of dissection are typical for this "vascular" subtype of Ehlers-Danlos syndrome.


Aspirin (tablets pictured) is commonly used after stroke. In vertebral artery dissection it appears as effective as anticoagulation with warfarin.


Girl with Wilson's disease showing neurological symptoms


A brown ring on the edge of the iris ( Kayser–Fleischer ring ) is common in Wilson's disease, especially when neurological symptoms are present.


Wilson's disease has an autosomal recessive pattern of inheritance.


Normal absorption and distribution of copper: Cu = copper, CP =  ceruloplasmin , green = ATP7B carrying copper


Location of the basal ganglia, the part of the brain affected by Wilson's disease


Ceruloplasmin


Hypothalamic interaction with the posterior and anterior pituitary glands. The hypothalamus produces the hormones oxytocin and vasopressin in its endocrine cells (left). These are released at nerve endings in the posterior pituitary gland and then secreted into the systemic circulation. The hypothalamus releases tropic hormones into the hypophyseal portal system to the anterior pituitary (right). The anterior pituitary then secretes trophic hormones into the circulation which elicit different responses from various target tissues. These responses then signal back to the hypothalamus and anterior pituitary to either stop producing or continue to produce their precursor signals.


Frequent serum GH measurements in normal subjects (left panel) demonstrate that GH can fluctuate between undetectable levels most of the time interspersed with peaks of up to 30 μg/L (90 mIU/L); in acromegaly (right panel) GH hypersecretion is continuous with no undetectable levels.


Magnetic resonance image  of a  pituitary macroadenoma  that caused acromegaly with compression of the  optic chiasm


Site of action of the different therapeutic tools in acromegaly.  Surgery ,  radiotherapy ,  somatostatin analogues  and  dopamine agonists  act at the level of the  pituitary adenoma , while  GH receptor antagonists  act in the periphery by blocking the  growth hormone receptor  and thus impairing the effects of GH on the different tissues.


Production of the  corticosteroid  hormone  cortisol  is increased after a person awakes in the morning


Comparative illustration from Talbot's 1889 work  Degeneracy : its causes, signs and results


Schematic of the HPA axis (CRH,  corticotropin-releasing hormone ; ACTH,  adrenocorticotropic hormone )


Hypothalamus, pituitary gland, and adrenal cortex


Schematic overview of the hypothalamic-pituitary-adrenal (HPA) axis. Stress activates the HPA-axis and thereby enhances the secretion of glucocorticoids from the adrenals.


Hypo gonadal axis


HPG regulation in males, with the inhibin/activin system playing a similar role on GnRH-producing cells


Estradiol, progesterone, LH, and FSH during the menstrual cycle.


Prolactin , a major hormone of the HPP axis.


Median sagittal section of brain of human embryo of three months


Endocrine glands  in the human head and neck and their hormones


Mitosis in a neuroendocrine tumor.


Lymph node metastasis of a neuroendocrine tumor


Synaptophysin  immunohistochemistry of neuroendocrine tumor, staining positively


Nuclei of neuroendocrine tumors often show granular  "salt-and-pepper" chromatin , as seen here on  H&E stain  and  Pap stain . [ 69 ]


Small intestinal  neuroendocrine tumor at bottom third of image, showing the typical  intramural  (within the wall) location, and overlying intact  epithelium .  H&E stain .


Magnocellular neurons of the PVN and SON project to the  posterior pituitary


Maternal affection, by  Edward Hodges Baily


Skin-to-skin contact with a newborn helps to increase the mother's oxytocin [ 20 ]


Plaque to Mary Pickford, Physiologist, at University of Edinburgh


Morphological  facial changes caused by acromegaly;  frontal bossing , enlarged nose,  prognathism  and  maxillary  widening with separation of teeth and unseen, enlargement of the tongue, stuffy nose ( macroglossia )


Pituitary gland


Pituitary hormones


Normal-sized hand (left) and enlarged hand caused by acromegaly (right)


Regulation of proopiomelanocortin by the photoperiod and thyroid hormones


Sst  is expressed in interneurons in the telencephalon of the embryonic day 15.5 mouse.  Allen Brain Atlases


Sst  expression in the adult mouse.   Allen Brain Atlases


D cell  is visible at upper right, and somatostatin is represented by middle arrow pointing left


Subfornical organ of a mouse. In this  photomicrograph , the subfornical organ (arrow) is located on the undersurface of the fornix in the upper part of the third ventricle.  The cells in this  coronal  section of the brain were colored with a bluish dye ( "Nissl  stain"). The  thalamus  is at the bottom of the photo. The bar at the lower right represents a distance of 200 μm (0.2mm).


Figure 1 : Human  steroidogenesis , showing testosterone near bottom [ 28 ]


Figure 2 . Hypothalamic–pituitary–testicular axis


Nobel Prize winner,  Leopold Ruzicka  of Ciba, a pharmaceutical industry giant that synthesized testosterone


Chemical structure of the arginine vasopressin (argipressin) with an  arginine  at the 8th  amino acid  position.  Lysine vasopressin differs only in having a  lysine  in this position.


Chemical structure of  oxytocin . Differs from AVP at only the 3rd and 8th position.


Polish  neurologist  Edward Flatau  greatly influenced the developing field of neurology. He published a human brain atlas in 1894 and wrote a fundamental book on migraines in 1912.


Jean-Martin Charcot  is considered one of the fathers of neurology. [ 8 ]


Axial section of the Brainstem (Pons) at the level of the Facial Colliculus


The Clivus


Limitation of  abduction  of the right eye. This individual tries to look to his right, but the right eye fails to turn to the side.


The accessory nerve supplies the  sternocleidomastoid  and  trapezius muscles


The nigrostriatal pathway (highlighted in blue) is crucial for dopamine production and transmission.


Location of the hypothalamus in the brain.


Dopamine pathways in the brain. The production of dopamine is concentrated in the Ventral Tegmental Area and the Substantia Nigra.


Brain anatomy


GABA-A receptor embedded in cell membrane


Parasagittal render of human brain with MRI


Man ready for EEG recording


Reactive astrocytes in a rat brain stained against GFAP.


Anatomy of the human ear (The length of the auditory canal is exaggerated in this image.).    Brown is  outer ear .      Red is  middle ear .      Purple is  inner ear .


Auditory ossicles from a deep dissection of the tympanic cavity


The  organ of Corti  located at the  scala media


Lateral lemniscus  in red, as it connects the  cochlear nucleus ,  superior olivary nucleus  and the  inferior colliculus , seen from behind


Dual stream connectivity between the auditory cortex and frontal lobe of monkeys and humans.  Top: The auditory cortex of the monkey (left) and human (right) is schematically depicted on the supratemporal plane and observed from above (with the parieto- frontal operculi removed). Bottom: The brain of the monkey (left) and human (right) is schematically depicted and displayed from the side. Orange frames mark the region of the auditory cortex, which is displayed in the top sub-figures. Top and Bottom: Blue colors mark regions affiliated with the ADS, and red colors mark regions affiliated with the AVS (dark red and blue regions mark the primary auditory fields). Abbreviations: AMYG-amygdala, HG-Heschl's gyrus, FEF-frontal eye field, IFG-inferior frontal gyrus, INS-insula, IPS-intra parietal sulcus, MTG-middle temporal gyrus, PC-pitch center, PMd-dorsal premotor cortex, PP-planum polare, PT-planum temporale, TP-temporal pole, Spt-sylvian parietal-temporal, pSTG/mSTG/aSTG-posterior/middle/anterior superior temporal gyrus, CL/ ML/AL/RTL-caudo-/middle-/antero-/rostrotemporal-lateral belt area, CPB/RPB-caudal/rostral parabelt fields. Used with permission from Poliva O. From where to what: a neuroanatomically based evolutionary model of the emergence of speech in humans.   Material was copied from this source, which is available under a  Creative Commons Attribution 4.0 International License .


Sagittal cross-section of the brain illustrating the dopaminergic pathway.


Benzodiazepines  are a type of tranquilizers used in the treatment of Bell's Mania that take effect by acting on   GABA  neurotransmitters in the brain. It helps in bringing extreme agitation and catatonia under control.


The use of Intramuscular Ketamine Injections is a popular method in the treatment of Bell's Mania.


Luther Vose Bell (1806-1862) was the first person to coin the term Bell's Mania.


Flow chart depicting the role of  apomorphine  in Alzheimer's disease.


An analog biothesiometer kit


A digital biothesiometer


Part of a network of  capillaries  supplying brain cells


The astrocytes type 1 surrounding capillaries in the brain


Sketch showing constitution of blood vessels inside the brain


Particulate exposure and increased risk of neurodegeneration [ 1 ]


Potential particle pathways as of 2018. [ 2 ]


A  scanning electron microscope  image of bundles of multiwalled  carbon nanotube  piercing an  alveolar epithelial cell .


Burning of downed vegetation, or " slash ".


Air-purifiers with air flow generated by  bladeless fan . Some models can act as heaters or  humidifiers  and may feature oscillation and adjustment of air flow angle.


First generation SALSCS (Solar-assisted Large Scale Cleaning System), Xi'an


Cerebrovascular system


The  ophthalmic artery  and its branches


The anterior and posterior circulations meet at the  circle of Willis , pictured here, which rests at the top of the  brainstem . Inferior view.


Dural venous sinuses  bordered by hard meninges (shown in blue) direct blood outflow from cerebral veins to the  internal jugular vein  at the  base of skull .


MRI showing pulsation of CSF


Distribution of CSF


Vials containing human cerebrospinal fluid


Coronal anterior section through anterior fontanelle of a one-year-old girl.


Mid sagittal section through anterior fontanelle of a one-year-old girl.


Striatum


Dopamine Pathways


Dopamine D2 receptors


Gamma-camera


An illustration of the standard Hodgkin–Huxley Na +  channel model


Transmembrane voltage response of a space-clamped mammalian  node of Ranvier


Diagram of a voltage-sensitive sodium channel α-subunit. G -  glycosylation , P -  phosphorylation , S - ion selectivity, I - inactivation, positive (+) charges in S4 are important for transmembrane voltage sensing.


Mean proportions of stimuli perceived as painful v. stimulus prepulse


Based upon the data presented in [ 2 ]


Referred pain : Conscious perception of visceral sensations is referred to specific regions of the body that are not sources of the sensations.  Some referred pain due to visceral sensations refer to dermatomes that send fibers to the same level of spinal cord.


Dermatomes of the lower limb (modified, from Fender, after Foerster)


Discoid lateral meniscus


Photograph of a congenital discoid menisci specimen from the University of Cape Town Pathology Learning Centre teaching collection.


Discoid meniscus on coronal proton-density weighted MRI


FOV both eyes


Vertical FOV


Angle of view  can be measured horizontally, vertically, or diagonally.


In  computed tomography  ( abdominal CT  pictured), the field of view (FOV) multiplied by  scan range  creates a volume of  voxels .


Field of view diameter in microscopy


Frontal lobe (red) of left cerebral hemisphere


Trajectory of a rat through a square environment is shown in black. Red dots indicate locations at which a particular entorhinal grid cell fired.


Grid cells derive their name from the fact that connecting the centers of their firing fields gives a triangular grid.


Spatial autocorrelogram of the neuronal activity of the grid cell from the first figure.


A hexagonal lattice.


In heterosynaptic plasticity, synaptic pathways that are not specifically stimulated undergo changes (synaptic plasticity) in addition to those who are specifically stimulated.


In modulatory input-dependent plasticity, Neuron C acts as an interneuron, releasing neuromodulators, which changes synaptic strength between Neuron A and Neuron B.


In  Aplysia californica,  modulatory interneurons release serotonin, triggering synaptic plasticity in motor neurons.


Schematic image of the hypoglossal nerve and innervation targets.


An injured hypoglossal nerve will cause the tongue to  waste away  and the tongue will not be able to stick out straight. The injury here occurred because of  branchial cyst  surgery.  [ 18 ]


Midline shift (arrow) is present in this brain after a  stroke  (infarct depicted in shaded area).


This  subdural hematoma / epidural hematoma  (arrows) is causing midline shift of the brain


Converging empirical evidence indicates a functional equivalence between action execution and motor imagery.


Activation in the motor cortex during motor imagery amounts about 30 % of the level observed during actual performance; Roth et al., 1996.


People have a conversation in a social setting


Schematic diagram of the experimental set-up in the rubber hand illusion task.


Superior colliculus


Depiction of  smooth muscle  contraction


Types of muscle contractions


In vertebrate animals, there are three types of muscle tissues: 1) skeletal, 2) smooth, and 3) cardiac


Organization of skeletal muscle


Structure of neuromuscular junction.


Picture showing the different interactions within the ECC pathway


Sliding filament theory: A sarcomere in relaxed (above) and contracted (below) positions


Cross-bridge cycle


Muscle length versus isometric force


Force–velocity relationship: right of the vertical axis concentric contractions (the muscle is shortening), left of the axis eccentric contractions (the muscle is lengthened under load); power developed by the muscle in red. Since power is equal to force times velocity, the muscle generates no power at either isometric force (due to zero velocity) or maximal velocity (due to zero force). The optimal shortening velocity for power generation is approximately one-third of maximum shortening velocity.


Swellings called varicosities belonging to an autonomic neuron innervate the smooth muscle cells.


Cardiac muscle


Key proteins involved in cardiac calcium cycling and excitation-contraction coupling


A simplified image showing earthworm movement via peristalsis


Asynchronous muscles power flight in most insect species. a: Wings b: Wing joint c: Dorsoventral muscles power the upstroke d: Dorsolongitudinal muscles (DLM) power the downstroke. The DLMs are oriented out of the page.


Electrodes touch a frog, and the legs twitch into the upward position [ 48 ]


This figure illustrates how glioblastoma affects brain tissue.


This diagram shows the myelin sheath around axons of healthy neurons looks like, and the result of demyelination of neurons in Multiple Sclerosis.


Edelman giving a lecture, September 30, 2010


Illustration of disulfide bridges (red) linking the light (L, green) and heavy (H, purple) chains of Immunoglobulin G (IgG) antibody. The variable (V) regions are located at the antigen-binding end; and, the constant (C) domains form the primary frame of the IgG molecule.  Another disulfide bridge holds the two symmetrical units made up of a light chain (V L +C L ) and a heavy chain (V H +C H 1+C H 2+C H 3) together to form the completed antibody. [ a ]


Clonal selection theory  (CST):  hematopoietic stem cells  (1) differentiate and undergo genetic rearrangement to produce a population of cells possessing a wide range of pre-existing diversity with respect to antibody expression (2).  Lymphocytes expressing antibodies that would lead to autoimmunity are filtered from the population (3), while the rest of the population represents a degenerate pool of diversity (4) where antigen-selected variants (5) can be differentially amplified in response (6).  Once the antigen has been cleared, the responding population will decrease, but not by as much as it was amplified, leaving behind a boosted capacity to respond to future incursions by the antigen – a form of enhanced recognition and memory within the system.


The degeneracy of the genetic code buffers biological systems from the effects of random  mutation . The ingenuous 1964  Nirenberg and Leder experiment  would identify the  mRNA   codons , a triplet sequence of  ribonucleotides , that coded for each  amino acid ; thus elucidating the  universal genetic code  within the  DNA  when the  transcription  process was taken into account. Changes in the third position of the codon, the  wobble position , often result in the same amino acid, and oftentimes the choice comes down to  purine  or  pyrimidine  only when a choice must be made.  Similar, but variant, codon sequences tend to yield similar classes of amino acid –  polar  to polar,  non-polar  to non-polar,  acidic  to acidic, and  basic  to basic residues.


The four major classes of biological amino acids – polar (hydrophilic), nonpolar (hydrophobic), acidic, and basic side chain residues.  The amino acid backbone is  amino  group linked to an  alpha carbon , on which resides the side chain residue and a hydrogen atom, that is connected to a terminal  carboxylate  group. Aside from the disulfide bridge, there are quite a number of degenerate combinations of sidechain residues that make up the  tertiary structure  ( H-bonding ,  hydrophobic , and  ionic bridges ) in the determination of protein structure.


Relationships between degeneracy, complexity, robustness, and evolvability – 1) degeneracy is the source of robustness. 2) degeneracy is positively correlated with complexity. 3) degeneracy increases evolvability. 4) evolvability is a prerequisite for complexity. 5) complexity increases to improve robustness. 6) evolvability emerges from robustness.


Mesenchymal-epithelial transitions – epithelia to mesenchyme (EMT) and mesenchyme to epithelia (MET) transitions utilizing CAMs and SAMs to form epethelia; and, growth factors and inducers to mediate the transition to mesenchyme as the CAMs and SAMs are withdrawn or localized on the cell membrane.


Normal Brain Development (left), Microcephaly, a type of encephalopathy (right)


Human embryonic stem colonies (A), axonal outgrowths (B)


Mouse Embryonic Stem Cells (mESCs) embryoid bodies (EBs)


Human Central Nervous System


Neuromuscular junction. 1. Axon innervating muscle fibers; 2. Junction between axon and muscle fiber; 3. Muscle; 4. Muscle fiber


The initiation of neuroinflammation in the body. (Created with BioRender.com)


Role of neuroinflammation in the pathophysiology of TBI (created with BioRender.com)


Impairment of neuron LTP by activated  microglia  (created with BioRender.com)


The neuroprotective and anti-inflammatory effects of exercise on cognitive diseases.


Children's ward at Rancho Los Amigos Hospital in 1954, showing more than 100 persons being helped to breathe by the  Iron lung


Walter Edward Dandy  (April 6, 1886 – April 19, 1946) was an American  neurosurgeon  and scientist.


ICU Monitor (front)


Micrograph  of a  vasculitic neuropathy . Plastic embedded.  Toluidine blue stain .


A neuron observed under an optical microscope


X-ray image of  deep brain stimulation , an experimental procedure used to treat disorders such as  OCD  and  depression .


Drawing by  Santiago Ramón y Cajal  (1899) of  neurons  in the pigeon cerebellum


Illustration from  Gray's Anatomy  (1918) of a lateral view of the  human brain , featuring the  hippocampus  among other neuroanatomical features


The  Golgi stain  first allowed for the visualization of individual neurons.


3-D sensory and motor homunculus models at the  Natural History Museum, London


Human nervous system


Photograph of a  stained neuron  in a chicken embryo


Proposed organization of motor-semantic neural circuits for action language comprehension. Adapted from Shebani et al. (2013).


An  MRI  of a male's head showing  benign familial macrocephaly  (head circumference > 60 cm)


The neurotrophic electrode: teflon-coated gold wires extend from the back of the glass cone, while neurites (shown in blue) grow through it.


A schematic of the neurovascular unit (NVU), where  astrocyte  processes surround the  capillary   basement membrane  and  pericytes , creating the  glia limitans . Also, resident in the  perivascular space  are  antigen-presenting cells  (APCs) and border-associated  macrophages  (BAMs).


Plasticity in the brain affects the strength of neural connections and pathways.


The neuronal soma, axon, and dendrites are involved in nonsynaptic plasticity and affect the plasticity at the synapse


Neurons interact in complex networks that affect the generation of action potentials in other neurons.


Action potential propagation animation


A  fundus photograph  showing the back of the retina. The white circle is the beginning of the optic nerve.


Writing and drawing performed by a child with dyslexia, displaying common behavioral symptoms.


Archaic Chinese logograms


Insertion of electrode during  deep brain stimulation  surgery using a  stereotactic frame


Myelin sheath  of a healthy  neuron  in the  central nervous system


Myelin sheath damage  in multiple sclerosis


Illustration of the four different types of glial cells found in the central nervous system: ependymal cells, astrocytes, microglial cells, and oligodendrocytes


Cross-section of lower pons, axons shown in blue, grey matter in light grey. Anterior is down and posterior is up


Chart showing symptoms of long COVID


Cells infected with  Epstein–Barr virus , one of the viruses implicated in PAISs


ME/CFS has many competing definitions.


Prepulse inhibition: preceding stimulus attenuates the  startle response .


PPI and startle reflex apparatus for mice


PPI measurement in human.


A circuit diagram of postsynaptic inhibition (A, B) and presynaptic inhibition (C). Excitation is shown in green and inhibition is shown in red.


Claude Bernard, the father of modern physiology, with his pupils


Bust of Hans Selye at  Selye János University ,  Komárno , Slovakia


Babinski sign


Myelin Sheaths in the CNS.


This figure depicts an example of combination of a forward model and an inverse model. Here the reference input is the target sensory state that controller (inverse model) will use to compute a motor command. The plant ( motor unit ) acts out the motor command which results in a new sensory state. This new sensory state can be compared to the state predicted by the forward model to  obtain an error signal. This error signal can be used to correct the internal model or the current movement.


1:posterior segment 2:ora serrata 3:ciliary muscle 4:ciliary zonules 5:Schlemm's canal 6:pupil 7:anterior chamber 8:cornea 9:iris 10:lens cortex 11:lens nucleus 12:ciliary process 13:conjunctiva 14:inferior oblique muscule 15:inferior rectus muscule 16:medial rectus muscle 17:retinal arteries and veins 18:optic disc 19:dura mater 20:central retinal artery 21:central retinal vein 22:optic nerve 23:vorticose vein 24:bulbar sheath 25:macula 26:fovea  27:sclera 28:choroid 29:superior rectus muscle 30:retina


The  homunculi  showing which parts of the body are controlled by the  sensory cortex  and  motor cortex . Taub's research on the Silver Spring monkeys challenged the  paradigm  that brain functions are fixed in certain locations.


Facial view of an infant with macrocephaly


Diagram illustrating the theorized causes of NAA accumulation in spongy degeneration patients and its consequences


Small volume of amniotic fluid is extracted via  amniocentesis  with a  syringe .


Molecular view of gene therapy using an adenovirus vector


Synaptic plasticity rule for gradient estimation by dynamic perturbation of conductances


Animation showing the position of the human left temporal lobe


Dermatome  distribution of the trigeminal nerve


Dermatome distribution of the trigeminal nerve


C = Cervical segment, S = Sacral segment, VPL =  Ventral posterolateral nucleus , SI =  Primary somatosensory cortex , VM =  Ventromedial prefrontal cortex , MD =  Medial dorsal thalamic nucleus , IL =  Intralaminar nucleus , VPM =  Ventral posteromedial nucleus , Main V =  Main trigeminal nucleus , Spinal V =  Spinal trigeminal nucleus


Brainstem nuclei: Red = Motor; Blue = Sensory; Dark blue = Trigeminal nucleus


Onion-skin distribution of the trigeminal nerve


Cortical homunculus


Tripartite Synapse: Presynaptic neuron, Postsynaptic neuron, and Glial cells


Presynaptic and postsynaptic neuron


The Cavernous Sinus


Parasympathetic nervous system mediated by vagal innervation


Visual field-tubular vision


Visual field-central scotoma


Visual field-bitemporal hemianopia


Visual field-binasal hemianopia


Visual field-homonymous hemianopia


Visual field-right superior quadrantanopia


Location of brain regions related to vitamin D


The brain of a normal adult compared to that of a patient with Alzheimer's disease


This image depicts the circuits of the basal ganglia in patients with Parkinson's disease. Pay close attention to the role of the  substantia nigra  and the dopaminergic neurons


The prevalence of MS is associated with latitude. In this image, red indicates a high prevalence of MS while yellow indicates a lower prevalence


Map of deficits in  neural tissue  throughout the human brain in a patient with schizophrenia. The most deficient areas are magenta, while the least deficient areas are blue.


A Wartenberg wheel


American Academy of Neurology


An advertising board in North London displaying an advert as part of the campaign


The  National Hospital for Neurology and Neurosurgery


Prof John Rothwell FMedSci


Prof Sarah Tabrizi FMedSci


1907 image of a brain


William James


The part of the picture emphasized shows the  lesion  in the brain. This type of lesion can be removed through surgery.


PET brain scans can show chemical differences in the brain between addicts and non-addicts. The normal images in the bottom row come from non-addicts while people with addictions have scans that look more abnormal.


Fruit fly ( Drosophila melanogaster ) leg joints being tracked in 3D with Anipose. [ 29 ]


Experimental setup for noninvasive theta-burst stimulation of the human striatum to enhance striatal activity and motor skill learning.


High resolution  fMRI  of the human brain.


Passage  by  Anna Sahlstén


Ascent of the Blessed  by  Hieronymus Bosch  is associated by some NDE researchers with aspects of the NDE. [ 15 ] [ 16 ]


Entering darkness, seeing the light


EEG  research data by Gang Xu,  et al .


Pim van Lommel


Animation of the human left temporal lobe


Labeling of different parts of a neuron


Dopamine and serotonin pathway


Orthosteric agonist (A) binds to orthosteric site (B) of a receptor (E). Allosteric modulator (C) binds to allosteric site (D). Modulator increases/lowers the affinity (1) and/or efficacy (2) of an agonist. Modulator may also act as an agonist and yield an agonistic effect (3). Modulated orthosteric agonist affects the receptor (4). Receptor response (F) follows.


CX614, a PAM for an AMPA receptor binding to an allosteric site and stabilizing the closed conformation


Structures of Anabaseine at Physiological pH


Synthesis of Anabaseine


Abstract simplified diagram showing overlap between neurotransmission and metabolic activity. Neurotransmitters bind to receptors which cause changes to ion channels (black, yellow), metabotropic receptors also affect DNA transcription (red), transcription is responsible for all cell proteins including enzymes which manufacture neurotransmitters (blue).


Diagram of neural circuit which regulates melatonin production via actual circuit pathways. Green light in the eye inhibits pineal production of melatonin (Inhibitory connections shown in red). Also shown:reaction sequence for melatonin synthesis.


Various  psychoactive  drugs


The common  muscimol -bearing mushroom  Amanita muscaria  (fly agaric)


Escitalopram , a selective serotonin reuptake inhibitor (SSRI) used as an antidepressant.


Tiagabine , a selective GABA reuptake inhibitor used as an anticonvulsant in the treatment of epilepsy and seizures.


Reserpine , a vesicular reuptake inhibitor that was used in the past to deplete serotonin, norepinephrine, and dopamine stores as an antipsychotic and antihypertensive. It was notorious for causing anxiety and depression, and as a result, was replaced by newer, more modern drugs instead.


Hyperforin , the primary active constituent responsible for the therapeutic benefits of extracts of the herb  Hypericum perforatum  (St. John's Wort), which is used as an antidepressant.


RD and gambling disorder


C. Robert Cloninger


MRI


The brain on substance dependence.


Type 2 Alcoholism


When reward dependence goes wrong


Phenelzine  is a  MAOI  which contributed to SS in the  Libby Zion  case


Cover of the Journal Meditsinskii Rabotnik (Medical Worker) (1927) No. 47: "Prof. Fokht za izucheniem srezov mozga Lenina" (Professor Vogt investigating histological sections from Lenin’s brain)


Neuroscientists  Oskar Vogt  and  Cécile Vogt-Mugnier


Vladimir Ilyich Ulyanov


Convulsionnaires confined to the  Bastille , 18th-century engraving.


François de Pâris at prayer.


Artistic portrayal of  secours  at a convulsionnaire meeting. Anonymous engraving from the eighteenth century.


Portrait of Charles Gaspard Guillaume de Vintimille du Luc, Archbishop of Paris


Trepanned   Incan  skulls


Galen demonstrating the recurrent laryngeal nerves in public


Base of the brain in  De humani corporis fabrica  by  Andreas Vesalius , 1543


Paracelsus


Mesmer


De Puységur


Abbé Faria


Reichenbach


James Braid


Jean-Martin Charcot


Charcot demonstrating  hypnosis  on a " hysterical "  Salpêtrière  patient, "Blanche" ( Marie Wittman ), who is supported by  Joseph Babiński . [ 13 ]


Boris Sidis


Elizabeth Roboz Einstein (1904–1995), pioneering biochemist and neuroscientist from Hungary.


Riitta Hari, Finnish neuroscientist, at the Science Forum 2011 in Helsinki.


Nathalie Zand of Poland


Engraving of the Hospital made around 1660 by Adam Pérelle


1857 lithograph by  Armand Gautier , showing personifications of  dementia ,  megalomania ,  acute mania ,  melancholia ,  idiocy ,  hallucination ,  erotomania  and  paralysis  in the gardens of the Hospice de la Salpêtrière


Pitié-Salpêtrière Hospital chapel


Chapelle de la Salpêtrière .


Pinel's monument at La Salpêtrière by  Ludowig Durand , sculptor, 1885 [ 19 ]


A Buck reflex hammer


The Taylor hammer appears on the far left. The other tools, from top to bottom, are: Babinski hammer, Queen square hammer,  Wartenberg wheel , and Buck hammer (disassembled to show components).


The  Queen Square  reflex hammer, shown with a plastic handle and a tip that tapers to allow for  plantar reflex  testing


Trömner reflex hammer


Charcot demonstrating hypnosis on a Salpêtrière patient, who is supported by  Joseph Babiński


Audiological exam


Examples of the onset and recovery of the acoustic reflex measured with a  laser Doppler velocimetry  system.


Anatomy of the human ear. (The length of the auditory canal is exaggerated for viewing purposes.)    Brown is  outer ear .      Red is  middle ear .      Purple is  inner ear .


Audiogram


Audiogram showing a typical "noise notch" in the left ear (normal hearing in the right ear)


New age portable digital audiometer


Portable audiometer  Maico , circa 1960s


Wireless audiometer which works on mobile devices via wireless connectivity i.e. Bluetooth and Wifi


Hearing care professional performing a hearing test on a client, 2015


Graph showing a typical Auditory Brainstem Response


Coronal section  of a human brain. BA41(red) and BA42(green) are auditory cortex. BA22(yellow) is  Brodmann area 22 , HF(blue) is  hippocampal formation  and pSTG is posterior part of  superior temporal gyrus .


Human ear anatomy.    Brown is  outer ear .      Red is  middle ear .      Purple is  inner ear .


Figure A – adapted from Gelfand (2004) [ 1 ]


Figure B – Adapted from Ehmer


Figure C – Adapted from Gelfand 2004 [ 1 ]


Figure D – Adapted from Gelfand 2004 [ 1 ]


Figure E – adapted from Moore 1998 [ 5 ]


Figure F – adapted from Moore 1998 [ 5 ]


Figure G – adapted from a diagram by Gelfand [ 1 ]


Figure H – adapted from Moore 1998 [ 5 ]


figure I – ipsilateral simultaneous masking


Lateral view of the human  cerebrum  showing the location of auditosensory cortex.


Section of brain showing the position of the human temporal lobe. The brain functional areas are highlighted above, with the auditory area in green.


Cytoarchitectonics of Brodmann 41 (Auditosensory cortex)


Hearing Aid


Infant wearing hearing aid


The wide field view of the endoscope allows "looking around the corner" while utilizing the natural ear canal access to cholesteatoma.


3D model of cochlea and semicircular canals


Structural diagram of the cochlea showing how fluid pushed in at the oval window moves, deflects the cochlear partition, and bulges back out at the round window.


1994 body-worn Cochlear Spectra processor. Early cochlear implant users utilized body-worn processors like this one


Cochlear implant recipient utilizing a behind-the-ear processor


Robin Michelson - Early creator of the Cochlear Implant


Internal components of a conventional device (not yet implanted)


A crowded  cocktail  bar


The International Symbol for Deafness is used to identify facilities with hearing augmentation services, especially  assistive listening devices . [ 4 ]


The flag of the deaf community made by  Arnaud Balard


An  audiologist  conducting an  audiometric   hearing test  in a  sound-proof  testing booth


Cotton otoblockers that are used to prevent the impression material from hitting the tympanic membrane


Impression material being mixed together. This is the start of the mixing process, as the material needs to be one color.


Gun/pistol for earmolds


Syringe that can be used for earmolds


Impression material hardening in the external ear canal


The external ear canal probe on an ear scanner


Pre-molded earplugs (left), formable earplugs (center), and roll-down foam earplugs (right)


Badly-inserted earplug, semi-inserted earplug, and properly-inserted earplug


Earplugs with probe for MIRE measurements of noise exposure on the worker's eardrums


Disposable foam earplugs: with coins for scale (top) and inserted into the wearer's ear.


Earplugs with instructions for use


Flanged earplugs made from silicone rubber. The hole in the left plug is the input port and extends as far as the central flange where the attenuation occurs


Musicians' earplugs. The grey end caps contain an acoustic transmission line with a damper (attenuator) at the end while the domed flanges form a seal in the ear canal. The output port can just be seen as a small hole at the near end of the left plug


Custom earplugs worn by professional musicians


Lead singer of the metal band  Sepultura   Derrick Green  wearing a custom earplug


Noise attenuation, earplugs EP100. The difference between laboratory predictions  (top) and real-world data [ 37 ]  (bottom)


Fit testing (MIRE) [ 51 ]


Earplugs are a form of hearing protection


Human ear anatomy, with the cochlea "uncoiled" showing frequency mapping to different regions of the basilar membrane.


Cross-sectional view of the organ of Corti within the cochlea. The basilar membrane is labeled "basilar fiber."


Example of transportation noise and how it affects the community.


Aircraft noise has been linked to high annoyance, leading to psychological-illness.


A typical mammalian middle ear: sound makes the tympanum (eardrum) vibrate; 3 small bones, the malleus, incus and stapes, transmit the vibrations to the labyrinth (inner ear), which transforms the vibrations into nerve signals.


Upper and lower portions of a python skull, displaying multiple bony components of the upper and lower jaws. Courtesy of the Peabody Museum of Natural History; Division of Vertebrate Zoology; Yale University.


Mammalian and non-mammalian jaws. In the mammal configuration, the  quadrate  and  articular  bones are much smaller and form part of the middle ear. Note that in mammals the lower jaw consists of only the  dentary  bone. [ 24 ]


Morganucodontidae  and other transitional forms had both types of jaw joint:  dentary - squamosal  (front) and  articular - quadrate  (rear).


Headphones on a stand


Telephone operator  with a single head-mounted telephone-receiver (headphone), 1898


Wireless telegrapher   Reginald Fessenden  with two head-mounted telephone-receivers (headphones), 1906


Holtzer-Cabot  telephone operator head receiver, wireless operator receiver, and telephone receiver, 1909


Sennheiser  HD 555 headphones, used in  audio production  environments (2007)


Headphone cord with integrated  potentiometer  for volume control


Circumaural headphones have large pads that surround the outer ear.


A pair of supra-aural (on-ear) headphones


In-ear monitors extend into the ear canal, providing isolation from outside noise.


A typical example of a headset used for  voice chats


Sony Ericsson  Cordless bluetooth headset


Aviation headset [ 46 ]


In-ears are among those good for noise isolation.


A typical moving-coil headphone transducer


Electrostatic loudspeaker diagram


A custom in-ear monitor which uses 8 balanced armatures in a triple crossover configuration (4 low/2 mid/2 high). Headphone designs often use multiple balanced armatures to provide a higher fidelity sound.


Sony MDR-7506 headphones in stowed configuration


A micro audio amplifier for boosting the output power of  smartphones  etc. to headphones. Used for example to compensate a built-in volume limit in smartphones, the higher volume levels could, however, lead to ear damage.


Product testing - headphones in an  anechoic chamber


Schematic diagram of the human ear [ clarification needed ]


The middle ear uses three tiny bones, the malleus, the incus, and the stapes, to convey vibrations from the eardrum to the inner ear.


The inner ear is a small but very complex organ.


The  lateral lemnisci  (red) connects lower brainstem auditory nuclei to the  inferior colliculus  in the midbrain.


A cat can hear high-frequency sounds up to two octaves higher than a human.


A modern behind the ear hearing aid. The audio tube to the speaker is barely visible.


A modern behind the ear hearing aid with a minicell battery


1940s adult and child combined hearing aid glasses, on display at  Thackray Museum of Medicine . [ 26 ]


A sign in a train station explains that the public announcement system uses a "Hearing Induction Loop" ( audio induction loop ). Hearing aid users can use a telecoil (T) switch to hear announcements directly through their hearing aid receiver.


A hearing aid with an audio boot


A DAI plug on the end of a cable


Block diagram of digital hearing aid


Madame de Meuron  with ear trumpet


Hearing aid shop,  Dublin , Ireland


Workers cutting marble without any protective gear. Photo taken in Indore, India


Different types of Earplugs


Orange safety earmuff


A deaf person using a camera-equipped smartphone to communicate in sign language


An  audiologist  conducting an  audiometric   hearing test  in a  sound-proof  testing booth


An in-the-canal hearing aid


Disability-adjusted life year  for hearing loss (adult onset) per 100,000 inhabitants in 2004:             no data      <250      250–295      295–340      340–385      385–430      430–475          475–520      520–565      565–610      610–655      655–700      >700


The sign for "friend" in  American Sign Language


Various earmuff hearing protectors.


Sound levels of some daily activities


Earmuff hearing protection device.


Different styles of earplugs are pictured. Left, pre-molded earplugs. Center, formable earplugs. Right, roll-down foam earplugs.


A U.S. Soldier wearing a hearing protection and communications headset.


Custom earplug hearing protection devices.


Noise reduction, earplugs EP100 (Willson). Top: measurements in the laboratory, and performance ratings. Bottom: real-world data [ 34 ]


HPD  fit testing [ 23 ]


An example of a  NIOSH  mobile laboratory for measuring sound thresholds, and the real attenuation of workers earplugs [ 44 ]


Fit testing (MIRE) [ 1 ]


NIOSH  mobile laboratory for REAT measuring (sound thresholds & real attenuation of earplugs) [ 21 ]


Earplugs with probes for MIRE measurements.


Logarithmic chart of the hearing ranges of some animals [ 1 ] [ 2 ]


Human hearing area in frequency and intensity. Dashed line describes possible changes due to excessive hearing strain (e.g. loud music).


An audiogram showing typical hearing variation from a standardized norm.


Outer ear ( pinnae ) of a cat


Dolphins


Loudness discomfort levels (LDLs) : group data of hyperacusis patients without hearing loss. Upper line: average hearing thresholds. Lower long line: LDLs of this group. Lower short line: LDLs of a reference group with normal hearing. [ 40 ]


Hyperacusis patient wearing ear protection


Inner ear


The  cochlea  and  vestibule , viewed from above.


A cross-section of the  cochlea  showing the  organ of Corti .


Cross-section through the spiral organ of Corti at greater magnification.


Logo International Society of Audiology


The legend to this puzzle reads "Here is a class of a dozen boys, who, being called up to give their names were photographed by the instantaneous process just as each one was commencing to pronounce his own name. The twelve names were Oom, Alden, Eastman, Alfred, Arthur, Luke, Fletcher, Matthew, Theodore, Richard, Shirmer, and Hisswald. Now it would not seem possible to be able to give the correct name to each of the twelve boys, but if you practice the list over to each one, you will find it not a difficult task to locate the proper name for every one of the boys." [ 4 ]


Listening in conversation.


Audiograms  illustrating normal hearing (left) and unilateral low-pitch hearing loss associated with Ménière's disease (right)


Loudness discomfort levels (LDLs) – data of people with hyperacusis without hearing loss. Upper line: average hearing thresholds. Lower long line: LDLs of this group. Lower short line: LDLs of a reference group with normal hearing. [ 15 ]


The middle ear matches mechanical impedance, like a lever.


A hearing aid such as this one may be used to help alleviate MES in some patients.


Graph of a simple  sine wave


Flowchart of sound passage - outer ear


Flowchart of sound passage - middle ear


Flowchart of sound passage - inner ear


Levels of transmission of neural auditory signals


A  Qantas   Boeing 747-400  passes close to houses shortly before landing at  London Heathrow Airport .


Traffic  is the main source of  noise  pollution in cities like  São Paulo , shown here.


More than a quarter of US residences have average outside noise levels exceeding the maximum nighttime outside noise level recommended by the World Health Organization. [ 10 ]


Depiction of frequency weighting


A  sound level meter  is one of the main tools for measuring sounds in the environment and the workplace.


Measuring the noise level from a leaf blower using the NIOSH Sound Level Meter app


The  CityLink   sound tube  in  Flemington ,  Melbourne ,  Australia , is designed to reduce  roadway noise  without detracting from the area's aesthetics.


A man inserting an earplug in his ear to reduce the noise exposure


NIOSH  Occupational Noise Exposure Criteria Document


The outer ear receives sound, transmitted through the  ossicles  of the middle ear to the  inner ear , where it is converted to a nervous signal in the  cochlear  and transmitted along the  vestibulocochlear nerve


Example audiogram of a notch-shaped high frequency hearing loss.


Cross-section of the  cochlea . The inner hair cells are connected to  afferent  nerve fibers, and the outer hair cells are connected to  efferent  nerve fibers.


Abnormal features of Noonan syndrome at the age of 3 months: Note the eyebrow slant and left-side eyelid dropping. [ 6 ]


Abnormal features of Noonan syndrome at the age of 3 months: Note the low-set, posteriorly rotated, and abnormally formed ear. [ 6 ]


NS is typically inherited in an  autosomal dominant  pattern with variable expression.


The oldest known case of NS, described in 1883 by Kobylinski


Graph of prevalence of hearing loss over time for workers in various sectors in the United States [ 1 ]


The NIOSH Sound Level Meter app


NIOSH Hierarchy of Controls


The mammalian olivocochlear bundle, divided into medial (red) and lateral (green) systems. Both contain crossed and uncrossed fibres. The predominant fibres are represented by a thicker line. The insert (far left) shows the position of the cell bodies of the MOCS and LOCS relative to the MSOC and LSOC respectively, as observed in mammals.


The basic MOC acoustic reflex. The auditory nerve responds to sound, sending a signal to the cochlear nucleus. Afferent nerve fibres cross the midline from the cochlear nucleus to the cell bodies of the MOCS (located near the MSOC), whose efferent fibres project back to the cochlea (red). In most mammals, the majority of the reflex is ipsilateral (shown as a thicker line), effectuated by the crossed MOCS.


Attentional filter depths from 12 subjects who underwent a vestibular neurectomy, for the same ear (triangles) or different ears (crosses). Combined mean (----) and 95% confidence intervals are shown. An average ~15% decline in attentional filter depth can be seen following olivocochlear bundle (OCB) lesion. Data taken from Scharf et al. (1997). [ 26 ]


Cross-section through the spiral organ of Corti at greater magnification, showing position of the hair cells on the basement membrane.


Image showing the  outer ear ,  middle ear , and  inner ear , and how sound is conducted through the outer ear, to the  ossicles  of the middle ear, through to the inner ear and the cochlea, where the organ of Corti sits.


Otitis media


Perforation of the right tympanic membrane resulting from previous severe acute otitis media


Disability-adjusted life year  for otitis media per 100,000 inhabitants in 2004.             no data      < 10      10–14      14–18      18–22      22–26      26–30          30–34      34–38      38–42      42–46      46–50      > 50


Deaths from otitis media per million persons in 2012     0    1    2–4


CT scan of otosclerotic focus in the anterior footplate


Endoscopic Stapedotomy


Endocopic view of the ear with the piston inserted into the stapedotomy


Interaural attenuation with bone conduction


Figure 10: Speech recognition threshold (SRT) with noise. To aid explanation of this concept the CHL and the SNHL have the same magnitude of hearing loss (50 dBHL). The horizontal part of the curves is where the noise is inaudible. Thus, there is no masking effect on the SRT. The horizontal portion of the curve for the SNHL and CHL extends further than that for a normal hearing person, as the noise needs to become audible to become a problem. Thus, more noise has to be applied, to produce a masking effect. At the right hand side of the graph, to identify 50% of the speech correctly, the speech needs to much more intense than in the quiet. This is because at this end of the graph, the noise is very loud whether the person has a hearing loss or not. There is a transition between these two areas described. Factor A is a problem only in low noise levels, whereas Factor D is a problem when the noise level is high.


Silicone probe tubes used for real ear measurement.


Man listening through headphones


The logo for the Make Listening Safe initiative of the  World Health Organization


Elementary school boy with  headphones


Live rock concert at indoor entertainment venue


Figure 3: Cross-section of the cochlea.


Figure 4: Neural tuning curve for normal hearing.


Figure 5: Neural tuning curve for OHC loss. Adapted from. [ 14 ]


Figure 6: Neural tuning curve for OHC front row loss and IHC loss. Adapted from. [ 14 ]


Figure 7: Response of the basilar membrane to a pure tone.


Figure 8: Response of the basilar membrane to a pure tone, when there is a dead region.


Figure 9: Psychoacoustical tuning curve.


Noise Exposure Limits


Speech Banana


Safety sign from the UK Government Regulations requiring ear protection


A LectroFan white noise machine


Tympanometry in a boy in  Cameroon .


Tympanostomy tubes of varying size and shape. Examples of short-term use grommet (left) and long-term use T-shape (right).


Tympanostomy tube in the eardrum, draining fluid from the middle ear during an ear infection.


The Weber test is administered by holding a vibrating tuning fork on top of the patient's head.


Logo of the World Hearing Day


2024 World Hearing Day, "Changing mindsets"


2023 World Hearing Day, "Ear and hearing care for all!"


2023 World Hearing Day, "To hear for life listen with care!"


Logo for the 2020 World Hearing Day


Logo for Wiki4WorldHearingDay2019


Altered vision by SOM during daylight driving.


Altered vision by SOM during night driving.


When light enters one eye, it is detected by retinal photoreceptors and transmitted via the optic nerve to the pretectal nucleus in the midbrain. From there, signals are sent bilaterally to the Edinger-Westphal nuclei, which send parasympathetic fibers via the oculomotor nerves to the ciliary ganglia. These fibers innervate the sphincter pupillae muscles in both eyes, causing both pupils to constrict—the direct response in the stimulated eye and the consensual response in the other eye. This bilateral response ensures equal pupillary adjustment to light.


Changes in the impact factor of PCN


This drawing compares a normal neuron to one undergoing chromatolysis after axonal injury.  Regeneration after axonal injury may occur.


The idea of the cortical homunculus was created by  Wilder Penfield .


Nerve injury classification table of temperatures required for injury and pain relief [ 4 ] [ 5 ] [ 6 ]


An adult male undergoing pre-op preparation for deep brain stimulation


Insertion of electrode during surgery using a  stereotactic frame


Arteriogram of the arterial supply that can hemorrhage during DBS implantation


Chronic subcortical electrode implant in a laboratory rat used to deliver electrical stimulation to the brain.


Stereotactic apparatus used to insert an electrode into the  basal ganglia  of the brain, for Parkinson's disease surgery.


This is sample data table showing what data obtained from electromyoneurography looks like. Findings are measured in the form of amplitude (mV), latency (ms), and velocity (m/s) of the injured radial nerve, before and after surgery.


Action potential propagation animation


Acquisition of information on the position of the markers in 2D through the chambers of the left and right, this combination of information giving rise to a 3D image on the position of the markers


Medical gait photography, 1918


Gait analysis laboratory equipped with infrared cameras and floor mounted  force platforms


Walking sequences recorded by  motion capture


Corrective glasses are used to treat visual dyslexia


Spinal nerve Sympathetic ganglion multilingual


Sensory NCS : An example screenshot showing the results of a sensory nerve conduction velocity study of the right median nerve.


Cerebral Edema that resulted from brain tumor is represented by darker areas on this CT image


Molecular structure of Urea


Molecular structure of Glycerol


Molecular structure of Mannitol


Saline solution prepared for medical use by dissolving NaCl in water


Planning  CT scan  with IV contrast in a patient with left cerebellopontine angle  vestibular schwannoma


A doctor performing Gamma Knife Radiosurgery


NRC  graphic of the Leksell Gamma Knife


Transcranial doppler ultrasound analyzer of blood velocity


Spectral density plots right and left  middle cerebral arteries  cross-amplitude plots in men.


Facial Paradigms


Close-up of needle and catheter tip, showing the curved end at the needle's tip. The needle features an anti-coring curve at its tip  designed to cause a catheter passing through the needle's lumen to exit laterally at a 45 degree angle.


Figure 4.1: Metabolism of phenylalanine requires BH4 and also produces tyrosine. Deficiencies in cofactor or phenylalanine hydroxylase can result in phenylketonuria.


Figure 4.3: Metabolism of tryptophan to melatonin.


Figure 4.4: Glutamate metabolism as it interfaces with nitrogen transport and synthesis of GABA.


Figure 4.6: Metabolism of methionine. Remethylation and transsulfuration of homocysteine are illustrated. Cofactor or enzymatic deficiencies can result in an elevation of homocysteine.


Figure 2.1: Synthesis and degradation of acetylcholine.


Figure 2.2: ACh release and degradation. (A: acetyl-CoA; ACh: acetylcholine; AChE: acetylcholine esterase; Ch: choline; VAChT: vesicular ACh transporter)


Figure 2.3: Glutamate and GABA synthesis. (α-KG: α-ketoglutarate; PLP: pyridoxal phosphate)


Figure 2.4: Glutamate release and reuptake. (EAAT: excitatory amino acid transporters)


Figure 2.5: GABA and glycine release.  (GAT: cotransporters for GABA; VIAAT: vesicular inhibitory amino acid transporter)


Figure 2.6: Synthesis of dopamine, norepinephrine, and epinephrine.


Figure 2.7: Histamine synthesis.


Figure 2.8: Histamine release and reuptake. (ALDH: aldehyde dehydrogenase; DAO: diamine oxidase; HA: histamine; HNMT: N-methyltransferase; IA: imidazole acetaldehyde; IAA: imidazoleacetic acid; IAAR: imidazoleacetic acid riboside; NMH: N-methylhistamine; N-MIA: methylimidazole acetaldehyde; N-MIAA: N-methylimidazoleacetic acetic acid; OC3: organic cation transporter 3; PMAT: plasma membrane monoamine transporter)


Figure 2.9: Serotonin synthesis.


Figure 1.1: Potential fates of glucose oxidation. i. Glucose is oxidized to lactate; ii. Glucose is oxidized through the pentose phosphate pathway (PPP); iii. Glucose is stored as glycogen, which only occurs in astrocytes; iv. Pyruvate can be oxidized through the mitochondria but is not a primary fate. (GLUTs: glucose transporters; MCTs: monocarboxylate transporters; TCA: tricarboxylic acid; DHAP: dihydroxyacetone phosphate; GA3P: glyceraldehyde 3-phosphate)


Figure 1.2: Comparison of neuron and astrocyte metabolism. (PDH: pyruvate dehydrogenase complex; PKM1/2: pyruvate kinase isoforms M1 and M2; TCA: tricarboxylic acid; DHAP: dihydroxyacetone phosphate; GA3P: glyceraldehyde 3-phosphate)


Figure 1.3: Lactate and glutamate shuttling between the astrocyte and the neuron. (GS: glutamine synthetase; GLS: glutaminase; LDH: lactate dehydrogenase; EAATs: excitatory amino acid transporters; MCT: monocarboxylate transporter; GluR: glutamate receptor).


Hieroglyph  designating the brain or skull in the  Edwin Smith papyrus


One of Leonardo da Vinci's sketches of the human skull


A graph showing the threshold for nervous system response


3-D sensory and motor homunculus models at the  Natural History Museum, London


The remaining twenty-two brains from the collection are stored at the  Wistar Institute


Selection of  Primate  skulls


Pithecometra : In the frontispiece from his 1863  Evidence as to Man's Place in Nature ,  Thomas Huxley  compared skeletons of apes to humans.


A head-measuring tool designed for anthropological research in the early 1910s.  Theodor Kocher  was inventor of the craniometer. [ 3 ]


Illustration from "The Speaking Portrait" (Pearson's Magazine, Vol XI, January to June 1901) demonstrating the principles of Bertillon's anthropometry


A Bertillon record for  Francis Galton , from a visit to Bertillon's laboratory in 1893


A chart from Bertillon's  Identification anthropométrique  (1893), demonstrating how to take measurements for his identification system


Anthropometry demonstrated in an exhibit from a 1921  eugenics  conference


An 1839 drawing by  Samuel George Morton  of "a Negro head …, a Caucasian skull …, a Mongol head"


Plaster face casts of  Nias  islanders collected by J. P. Kleiweg de Zwaan, circa 1910


Charcot demonstrating  hypnosis  on a " hysterical "  Salpêtrière  patient, "Blanche" ( Marie Wittman ), who is supported by Babiński  (rear) . Note the  similarity to the illustration on the back wall . [ 2 ]


Swammerdam's illustration of a nerve-muscle preparation.  He placed a frog thigh muscle in a glass syringe with a nerve protruding from a hole in the side of the container.  Irritating the nerve caused the muscle to contract, but the level of the water, and thus the volume of the muscle, did not increase.


Georg von Békésy in 1918


Typical recording of a Bereitschaftspotential


An early EEG recording done by Berger


Head of a rachitic child in the  New York Infant Asylum  (1895)


Stereograph designed by Paul Broca and manufactured by Mathieu


Map of Color of Skin: Figures indicate tint in Broca's scale


Louis Victor "Tan" Lebourgne's brain (by Pierre Marie)


Broca's area


"Senator Broca will henceforth give examples of behavior in line with his theories." Le Triboulet, February 1880.


Brodmann's diagram of the cerebral cortex with the areas he identified


Modern depictions of Brodmann areas


Burdenko on a 1962 Soviet stamp


Grave of William Benjamin Carpenter in  Highgate Cemetery


Carpenter in 1850


Cerletti's ECT machine preserved at Museo di Storia della Medicina in Rome


André Brouillet


Electrotherapeutic device invented by Charcot's teacher,  Guillaume Duchenne (1806–1875)


Albert Londe 's photograph of a male Salpêtrière patient exhibiting the same contortions as those displayed in Richer's charcoal drawing


A wood-engraved reproduction of Brouillet's painting by Henri Dochy (1851–1915) [ 9 ]


A human skull and measurement device from 1902


Pithecometra : In the frontispiece from his 1863  Evidence as to Man's Place in Nature ,  Thomas Huxley  compared skeletons of apes to humans.


Selection of  primate  skulls


William Z. Ripley 's map of the "cephalic index" in Europe, from  The Races of Europe  (1899)


An 1839 drawing by  Samuel George Morton  of "a Negro head… a Caucasian skull… a Mongol head."


Logo


Albumen print archived at the  National Library of Medicine  in Bethesda.  Duchenne's colleagues appended " de Boulogne " to his name to avoid confusion with the like-sounding name of Édouard-Adolphe Duchesne (1804–1869) who was a popular society physician in Paris. [ 5 ]


Woodcut illustration of Duchenne's  "appareil volta-électrique."


Demonstration of the mechanics of facial expression. Duchenne and an assistant  faradize  the mimetic muscles of "The Old Man."


Duchenne and his patient, an "old toothless man, with a thin face, whose features, without being absolutely ugly, approached ordinary triviality"


G.-B. Duchenne de Boulogne, Synoptic plate 4 from  Le Mécanisme de la Physionomie Humaine . 1862,  albumen print . In the upper row and the lower two rows, patients with different expressions on either side of their faces


Figure 20 from  Charles Darwin 's  The Expression of the Emotions in Man and Animals  (1872). Caption reads "FIG. 20.—Terror, from a photograph by Dr. Duchenne"


Plate III from  Charles Darwin 's  The Expression of the Emotions in Man and Animals . From Chapter VIII: Joy—High spirits—Love—Tender feelings—Devotion


George Combe , founder of the society, was a lawyer who devoted his later life to advancing phrenology around the world.


Einstein's brain was preserved after his death in 1955, but this fact was not revealed until 1978.


The  lateral sulcus  (Sylvian fissure) in a normal brain. In Einstein's brain, this was truncated.


Another rendition of Antiochus's illness depicting Erasistratus's presence during the ordeal.


Woodcut of Herophilus and Erasistratus in the Gardens of Adonis


A dog cortical map obtained by Ferrier using the electrical stimulation of the brain


Left  Siegfried Kalischer , Edward Flatau (points to a book),  Louis Jacobsohn-Lask ,  Bernhard Pollack , around 1900 in Berlin


First page of  Atlas of the human brain and the course of the nerve-fibres  (1894)


Template from the English edition of the brain atlas


Edward Flatau is preparing pictures for his brain atlas.


First page of  Das Gesetz der excentrischen Lagerung der langen Bahnen im Ruckenmark  (1897)


German edition of 1912  Die Migrane , one of the first modern books on migraine headaches in 20th century


Dr. med. E. Flatau. Nervous and mental diseases. Chmielna 60 Street [Warsaw]. Hours 5 pm and 1/2 till 7 pm and 1/2. This is medical doctor seal from a medical prescription issued on 27 August 1920.


First page of collected publications of the Neurological Laboratory of the Warsaw Scientific Society published in 1912


Grave of Edward Flatau in Warsaw


The iron's path, per Harlow [H] : 21


Cavendish, Vermont , 20 years after Gage's accident:  (a)  Region of the accident site (exact location uncertain);  (t)  Gage's lodgings, to which he was taken after his injury;  (h)  Harlow's home and  surgery . [ note 4 ]


Line of the  Rutland & Burlington Railroad  passing through " cut " in rock south of Cavendish. Gage met with his accident while setting explosives to create either this cut or a similar one nearby. [ note 4 ]


Explosive charge ready for fuse to be lit.  tamping  (sand or clay) directs blast into surrounding rock.


The "cone of uncertainty" for the path taken by the tamping iron. Gage's mouth was open at the moment of the explosion, and the front and back of his skull temporarily "hinged" apart as the iron entered from below, then were pulled back together by the resilience of soft tissues once the iron had exited through the top of Gage's head. [ 15 ]


Panel from  Bring Me the Head of Phineas Gage , a portrayal of Gage in popular culture [ 16 ]


A  nightcap  used as a bandage


The first known report of Gage's accident, understating the thickness of his tamping iron (by confusing its diameter with its circumference) and overstating the iron's length and the damage to Gage's jaw.  [ 21 ] [M] : 12  [ 22 ]  "[Gage's] fame is of the kind that is, and in his case literally so, thrust upon otherwise ordinary people", writes Malcolm Macmillan. [M] : 11


The entry damage to Gage's left cheek, and the raised bone fragment in the exit area above his forehead, are visible in this plaster cast taken in late 1849.  [ note 7 ]


"Disfigured yet still handsome". [T]  Note  ptosis  of the left eye and scar on forehead.


Bigelow presented Gage to the elite  Boston Society for Medical Improvement  in 1849. In this 1853 Society portrait,  Oliver Wendell Holmes  is seated second from left.


For a time Gage was "a kind of living museum exhibit" at  Barnum's American Museum  in New York City.


"Admittance  12 + 1 ⁄ 2  cents" (equivalent to about $5 in 2023). [ 25 ]  Gage briefly resumed exhibiting just before going to Chile, possibly to help finance that move; this advertisement appeared August 1852 in  Montpelier, Vermont .  [L1] : 175


New Hampshire Statesman ,  July 21,  1860  [ 33 ]


"[T]he mother and friends, waiving the claims of personal and private affection, with a magnanimity more than praiseworthy, at my request have cheerfully placed this skull in my hands, for the benefit of science." Gage's skull (sawed to show interior) and iron, photographed for Harlow in 1868.  [ 34 ]


Gage's brother-in-law (a  San Francisco city official ) and his family personally delivered Gage's skull and iron to Harlow.  [M10] : 646  [ 35 ]


Excerpt from record book,  Lone Mountain Cemetery , San Francisco, reflecting the May 23, 1860 interment of  Phineas B. [sic]  Gage  by undertakers  N. Gray & Co. [ note 12 ] (Position pointer over writing for transcription; click for full page.)


"I  dressed  him, God healed him", wrote physician  J. M. Harlow , who attended Gage after the "rude missile had been shot through his brain" [ 40 ]  and obtained his skull for study after his death. Shown here in later life, Harlow's interest in  phrenology  prepared him to accept that Gage's injury had changed his behavior. [ 41 ]


"The leading feature of this case is its improbability", wrote Harvard's Prof.  H. J. Bigelow  (seen here in 1854). His anti- localizationist  training predisposed him to minimize Gage's behavioral changes. [B] : 672


"Before the injury he was quiet and respectful." 1851 report, apparently based on information from Harlow, countering Bigelow's claim that Gage was mentally unchanged.


"Please deliver my iron bar to the bearer". While in Chile, Gage had his relative B.   R. Sweetland retrieve the tamping iron from Harvard's Warren Anatomical Museum. [ note 14 ]


A  Concord coach , likely the type driven by Gage in Chile [ 50 ]


The left frontal lobe  (red) , with Ratiu et al.'s estimate of the tamping iron's path [R1]


False-color representations of  cerebral fiber  pathways affected, per Van Horn et al. [V] : 3


"I have the pleasure of being able to present to you [a case] without parallel in the annals of surgery."  [H] : 3   Harlow's 1868 presentation to the  Massachusetts Medical Society [H] : tp   of Gage's skull, tamping iron, and post-accident history.


Harlow's 1868 paper on Gage was widely reported. [M] : 112-14   This item appeared in  Scientific American  for July 1868.


Boston Herald , 1907


"[Few objects] have attracted more visitors and spread farther the fame of the  Museum "  [ 27 ]  than its "most valuable specimen"—Gage's skull.  [ 82 ] : v


Phrenologists  contended that destruction of the mental "organs" of Veneration and Benevolence caused Gage's behavioral changes. Harlow may have believed that the Organ of Comparison was damaged as well.


Memorial plaque,  Cavendish, Vermont


Inscription on iron as seen in portrait detail:  ... [Phine]has P. Gage at Cavendish, Vermont, Sept. 14, 1848.  He fully   ...


The second portrait of Gage identified (2010) [ note 1 ]


Franz Joseph Gall examining the head of a pretty young girl


Experiment  De viribus electricitatis in motu musculari


Late 1780s diagram of Galvani's experiment on frog legs


Electrodes touch a frog, and the legs twitch into the upward position [ 13 ]


Luigi Galvani's  monument  in Piazza Luigi Galvani (Luigi Galvani Square), in  Bologna


Samuel Goldflam


The first illustration by Golgi of the nervous system. Vertical section of the olfactory bulb of a dog (in 1875).


Drawing by Camillo Golgi of a  hippocampus  stained with the silver nitrate method


Marble statue of Golgi at the University of Pavia


Camillo Golgi's house in Pavia


A human neocortical  pyramidal neuron  stained via Golgi technique. Notice the apical dendrite extending vertically above the soma and the numerous basal dendrites radiating laterally from the base of the cell body. Photo by Bob Jacobs, Colorado College.


Drawing of a  Purkinje cell  in the  cerebellum   cortex  done by Santiago Ramón y Cajal, clearly demonstrating the power of Golgi's staining method to reveal fine detail


Herophilos (right) teaching Anatomy, 1906, by  Veloso Salgado  ( NOVA Medical School ,  Lisbon )


Hubel in his lab, 1980


X-ray of Kölliker's hand, made by Röntgen on 23 Jan 1896


Advertisement for a Leucotome in the 1940s


A leucotome designed by Neurosurgeon John Crumbie,  Croydon Mental Hospital , 1955 [ 3 ]


Jean Lhermitte


Anatomical components of the limbic system


Location and basic anatomy of the hippocampus, as a  coronal section


James Leonard Corning  (1855–1923), American  neurologist  and pioneer of  neuraxial blockade


August Bier  (1861–1949), pioneer of  spinal anesthesia


Original drawing by  Fidel Pagés , explaining the technique of  epidural anesthesia


Fidel Pagés  visiting an injured man at the Docker Hospital in  Melilla , Spain during the  Second Melillan campaign  in 1909. The Docker Hospital was renamed after Pagés in 1926.


Angelo Mosso's 'human circulation balance.'


Wilhelm Roentgen, creator of the X-ray.


Cerebral angiogram showing a  transverse projection  of the  vertebro basilar  and  posterior cerebral  circulation.


Full body PET scan of an adult female.


MEG device with patient.


Godfrey Hounsfield, inventor of first CT scanner


Ramón y Cajal's drawing of the cells of the chick  cerebellum , from  Estructura de los centros nerviosos de las aves , Madrid, 1905


An example of part of an academic genealogy, a family tree, from Academic Family Tree (in this case from the Physics Tree), of four generations of  Isaac Newton 's academic ancestors and two generations of his academic descendants


Image of a Nissl-stained histological section through the  rodent   hippocampus  showing various classes of neurons.


The Pavlov Memorial Museum in  Ryazan , Pavlov's former home, built in the early 19th century [ 3 ]


Pavlov and his future wife, Seraphima Vasilievna, in 1880


A 1935 portrait of Pavlov by  Mikhail Nesterov


One of Pavlov's dogs with a surgically implanted  cannula  to measure  salivation ,  preserved  in the Pavlov Museum in  Ryazan , Russia


Pavlov (right) and his granddaughter Milochka pictured with  H. G. Wells  in 1924


Phrenological skull, European, 19th century. Wellcome Collection, London


The Phrenologist , a sketch by A.S. Hartrick, 1895


Numbered phrenological bust


A definition of phrenology with chart from  Webster's Academic Dictionary,   c.  1895


George Combe


1848 edition of  American Phrenological Journal  published by Fowlers & Wells, New York


American Institute of Phrenology (New York, 1893)


An 1887 phrenology chart


Purkinje effect: simulated appearance of a red geranium and foliage in normal bright-light ( photopic ) vision, dusk ( mesopic ) vision, and night ( scotopic ) vision


Personal sigil 1837


Ramón y Cajal, captain in the  Ten Years' War ,  Cuba , 1874


Self-portrait as a student, 1870s


Ramón y Cajal in his laboratory


Ramón y Cajal's 1906 Nobel certificate;  Museo Nacional de Ciencias Naturales , Madrid


Ramón y Cajal's illustration of the neuronal morphologies in the auditory cortex


The hospital on the plan of  Jouvin de Rochefort  [ fr ] , in 1672


The asylum in 1877


The  Sainte-Anne Chapel  [ fr ] , built by  Charles-Auguste Questel  in 1869


Gate No. 1,  Rue Cabanis  [ fr ]


One of the many galleries of the hospital, here the Pirandello Gallery


Le Guet , a statue by  Victorien Tournier  [ fr ]  (1900), was placed in the garden of the Sainte-Anne Hospital in Paris in 1947.


The  homunculi  showing which parts of the body are controlled by the  sensory cortex  and  motor cortex . Taub's research on the Silver Spring monkeys challenged the  paradigm  that brain functions are fixed in certain locations.


Phrenology chart attributed to Dr. Spurzheim. Lithograph submitted to the Library of Congress by  Pendleton's Lithography , 1834.


Hieronymus Bosch ,  The Extraction of the Stone of Madness


Detail from  The Extraction of the Stone of Madness , a painting by  Hieronymus Bosch  depicting trepanation ( c.  1488–1516 )


The perimeter of the hole in this trepanated  Neolithic  skull is rounded off by ingrowth of new bony tissue, indicating that the patient survived the operation.


Skulls from the  Bronze Age  exhibited at the Musée archéologique de Saint-Raphaël (Archeological Museum of  Saint-Raphaël ), found in  Comps-sur-Artuby  (France). The subjects survived operations.


Dr. John Clarke  trepanning a skull,  c.  1664 , in one of the earliest American portraits. Clarke is alleged to have been the first physician to have performed the operation in the  New England Colonies .


Trepanation instruments, 18th century; Germanic National Museum in Nuremberg


Figure 1.  Diagram of the frog heart preparation used by Loewi. Vagus nerve stimulation slows heart rate while accelerator (sympathetic) nerve stimulation speeds up heart rate.


Figure 2.   Loewi's experiment proving that neurotransmision was chemical, rather than electrical.


Original records from Loewi's experiment in 1921. Saline from the stimulated heart was added to the unstimulated heart whenever the number "2" is indicated in the graph.


The skeleton of Jakob Karrer, articulated by Vesalius in 1543


The Holy Roman Emperor,  Charles V , who was an important patron of Vesalius


A portrait of Vesalius from his  De Humani Corporis Fabrica  (1543)


Vesalius's  Fabrica  contained many intricately detailed drawings of human dissections, often in allegorical poses.


Andreas Vesalius by Pierre Poncet (1574–1640)


Base of the  brain , showing the  optic chiasma ,  cerebellum ,  olfactory bulbs , etc.


Clovis Vincent (1927)


Volta battery at the  Tempio Voltiano  museum, Como


A  voltaic pile


Volta explains the principle of the  "electric column"  to  Napoleon  in 1801.


Leopoldo Pollack , Aula Volta, 1787,  Old Campus of the University of Pavia


The chair and the blackboard of Alessandro Volta,  University History Museum  of the University of Pavia


Front page of  De vi attractiva ignis electrici


Wernicke's area animation


Whitman, age two, c. early 1944


Whitman around 1959 (age 18)


Whitman and Leissner at their wedding in 1962


Whitman's journal


Main building of the University of Texas at Austin.  Whitman fired at people on the ground from the observation deck.


The tower observation deck


Drawing by  Santiago Ramón y Cajal  (1899) of  neurons  in the pigeon cerebellum


Illustration from  Gray's Anatomy  (1918) of a lateral view of the  human brain , featuring the  hippocampus  among other neuroanatomical features


The  Golgi stain  first allowed for the visualization of individual neurons.


3-D sensory and motor homunculus models at the  Natural History Museum, London


Human nervous system


Photograph of a  stained neuron  in a chicken embryo


Proposed organization of motor-semantic neural circuits for action language comprehension. Adapted from Shebani et al. (2013).


An  MRI  of a male's head showing  benign familial macrocephaly  (head circumference > 60 cm)


A simple classification scheme for ASC. Sleep and dream states are distinguished from waking consciousness since they account for substantially different ways of the ability of memory formation and retrieval. Psychiatric diseases that go along with persistent changes of consciousness, like  schizophrenia , are covered with the term "pathological conditions". In contrast, the classification scheme includes intended and induced ASCs as well as general fluctuations of  neurotransmission , which are reversible and short-termed. One step further the graph suggests splitting induced ASCs in persistent and reversible states. Translated from German Schmidt & Majic. [ 7 ]


Diagram explaining how associative interference is caused


Illustration of the axo-axonic synapse formed between the terminal of presynaptic neuron and the axon of postsynaptic neuron.


Drawing of the cerebellar cortex, showing axo-axonic synapses (green) formed by Basket cell projections (pink) onto Purkinje cells (blue) at the axon hillock.


Modifications of the  epigenome  do not alter DNA.


Monozygotic twins  are identical twins.  Twin studies  help to reveal epigenetic differences related to various aspects of psychology.


The  hypothalamic pituitary adrenal axis  is involved in the  human stress response .


Sagittal cross-section of the brain illustrating the dopaminergic pathway.


Benzodiazepines  are a type of tranquilizers used in the treatment of Bell's Mania that take effect by acting on   GABA  neurotransmitters in the brain. It helps in bringing extreme agitation and catatonia under control.


The use of Intramuscular Ketamine Injections is a popular method in the treatment of Bell's Mania.


Luther Vose Bell (1806-1862) was the first person to coin the term Bell's Mania.


A flow chart representation of the BIA+ model for bilingual language processing including the word identification and task/decision subsystems.


An example of a point light display of an American Sign Language sentence. The biological motions of the signer can be observed through the motions of white dots, as they sign a sentence.


Fig. 1. Neuron and myelinated axon, with signal flow from inputs at dendrites to outputs at axon terminals. The signal is a short electrical pulse called action potential or 'spike'.


Fig 2. Time course of neuronal  action potential  ("spike"). Note that the amplitude and the exact shape of the action potential can vary according to the exact experimental technique used for acquiring the signal.


A neuron is represented by an RC circuit with a threshold. Each input pulse (e.g. caused by a spike from a different neuron) causes a short current pulse. Voltage decays exponentially. If the threshold is reached an output spike is generated and the voltage is reset.


Spike times and subthreshold voltage of cortical neuron models can be predicted by generalized integrate-and-fire models such as the adaptive integrate-and-fire model, the adaptive exponential integrate-and-fire model, or the spike response model. In the example here, adaptation is implemented by a dynamic threshold which increases after each spike. [ 22 ] [ 23 ]


Firing pattern of initial bursting in response to a step current input generated with the Adaptive exponential integrate-and-fire model. Other Firing patterns can also be generated. [ 26 ]


Stochastic spike generation (noisy output) depends on the momentary difference between the membrane potential V(t) and the threshold. The membrane potential  V  of the spike response model (SRM)  has two contributions. [ 51 ] [ 52 ]  First, input current I  is filtered by a first filter k.  Second the sequence of output spikes S(t) is filtered by a second filter η and fed back. The resulting membrane V(t) potential is used to generate output spikes by a stochastic process ρ(t) with an intensity that depends on the distance between membrane potential and threshold. The spike response model (SRM) is closely related to the Generalized Linear Model (GLM). [ 53 ] [ 54 ]


Spike arrival causes postsynaptic potentials (red lines) which are summed. If the total voltage V reaches a threshold (dashed blue line) a spike is initiated (green) which also includes a spike-afterpotential. The threshold increases after each spike. Postsynaptic potentials are the response to incoming spikes while the spike-afterpotential is the response to outgoing spikes.