raw_transcripts/lecture_12.txt

Good morning.

So welcome back.

Friday.

Monday.

We heard about stress.

Today we're going to talk about social bonding.

Before we kick off, I just want to remind everyone

about while you're doing this module, do keep checking your

anatomy.

So this is a page in the anatomy and your

guide.

So here's the web guide from lecture two.

There's a whole load of brain sections to memorise.

And here is where one of them goes by halfway

through, about halfway through this module.

Now a bit more.

So you keep playing with this.

Can you tell some easy ones in this?

Where's the cerebellum?

Where's the corpus callosum?

Where's the military bodies?

That's much harder, right?

So here's where it says Yeah.

What number?

Three bodies.

So if you thought that was the military bodies, well

done.

But this is the way.

Just keep testing yourself.

Where's the midbrain?

Where's the pons?

Where is the body?

Keep looking through this material.

As you go through this course, I'm going to provide

some new anatomy today.

That isn't the place to do with the hypothalamus picking

up on last week.

That story on Monday's lecture.

Okay.

So let's go to our slides.

So Monday's talk on stressed is quite negative most of

the time.

Stress is a part of our life.

You going to have to sit in exam for this

module.

That's inherently stressful.

But another key way in which our way in which

we deal with stress is part of that is our

friendship groups, our parents, our sisters and brothers.

All potentially killing all these people around us really help

as humans mitigate stress and other primates and some of

the species.

Here's an example of two types of what we might

call social bonding.

A parent with a child or two people who have

couple together romantically in the textbooks.

And the research on this topic of how do these

bonds form between these two groups.

This is known as affiliation, and we'll dive into that

in this lecture.

So there are many ways in which bonds form between

people of different species.

On the left at the top, down the top left

is humans holding hands.

In many cultures around the world, that's a way of

single signifying bonding.

Swans have an amazing kind of approach with their heads.

And I think the cutest one of all really is

the two old world monkeys who twine their tails together.

So these are the monkeys bond for life as partners.

And when they do that, they sit together with their

tails bound up.

You can go and see them in London Zoo.

They have, or at least the last time where the

London Zoo in the tropical house, they have two world

monkeys.

So these are these are some of the things we

see, but we don't there are groups studying humans or

a group studying monkeys, small number of groups.

But a lot of the time research has been done

on these animals is not rats, but actually voles.

Those turn out to be a fascinating story in terms

of our understanding of social bonding.

And for humans, what social bonding bonding is linked to

is love, the love we have for our parents, our

family, our friends, our partner, etc., and our children.

We don't know if these animals experience love, but they

have very similar biochemical effects in their brains to us.

And because we can study those in more detail, we

can understand that.

So I talk about social bonding in this lecture, but

the technical term is affiliation that encompasses the bonds between

individuals, partners who come together to produce children and the

parent parents that bond.

And look at the general process of that bonding in

the beginning part of this lecture and turn to the

parental bonds at the end.

So this I mentioned this this coupling up the social

bonding promotes adoption to the world.

You can cope better when you've got friends, to put

it another way, and stress, the social isolation which doesn't

occur is linked to a whole range of psychiatric disorders.

So it's an important endeavour in our society to improve

social bonding, really.

So here's the more of a longer and a bit.

One of the key things you need to learn in

this lecture is the word called specific to the ability

to recognise a specific.

So this is another species of the same of another

individual of your same species.

So as humans walking around, you can detect humans.

So you as the human, the most dangerous thing out

there for humans and most of their animals.

So you really do need to detect humans, but also

the most useful animal you probably interact with animals, I

imagine the vast majority of you.

So you need to be able to do that.

You don't really need to be able to recognise as

a human, but which humanism?

Who is it I'm recognising and then do I need

to remember to maintain a relationship with this person?

So this all comes under this bonding process of not

only do tend to find that is that is the

human.

I do know that human and I do need to

invest time with that humans.

So the there are a number of tasks that have

been used.

That's all fine in theory, but how do we test

that?

One is to look at approach.

So here are two dogs.

Dogs love to approach each other.

Are people that dog owners know this.

They love to get in and sniff each other's bottoms.

They do more than that.

They really get in there and get in there with

them with the urine and material to understand.

They do more than we do as humans.

They also need to learn to recognise and said who.

And there's a lot of work which cheap, cheap but

very, very similar to us humans.

But they have to identify the individual sheep they're interacting

with.

And again, that investment with sheep, how does the sheep

know its mother and how does the mother know which

individual lamb is its lamb to take care of?

And there's been research on that.

Now, how a lot of those animals do that is

through smell of action.

So in red highlighted that humans are a bit unusual

in other primates, that our visual system is so good

we can see people far off and we can hear

thing.

We can use that visual information to guide our social

interactions.

Not all other animals share that ability, and what they

do is use of actions that ferments.

You may be aware from popular culture are floating in

the air.

These are these are gas tight released chemicals that have

some role in humans, but most are important for other

species in terms of their their interrelationships.

But beyond you know, beyond that, we have a particular

organ in the brains of most vertebrates.

So we have here reptiles and mammals that's shown by

rats and a snake, and they have what's known as

a bomb or a nasal organ.

It detects in the air these, these pheromones I can

relay them to.

A particular bit of the brain illustrates that in both

species called the accessory olfactory bulbs.

So if you're smelling like a beautiful perfume, you'll likely

be using your main olfactory system to detect that process

that, Oh, this is lovely and it passes through your

factory system.

Separate to that main pathway is the access, the real

factory bulbs, and they're helpful for detecting those social cues

in these.

So they pass that information that's shown here to the

thalamus, that campus and the amygdala to various other bits

of the brain that we'll come see.

So this will really keep it to the brain to

do that.

Social detection, Who is this?

And that's what we're looking for, the vulnerable nasal organism,

very much in action in that picture.

The two dogs, humans don't seem to have a formal

gaze.

Morgana starts to develop in the womb when you're a

tiny baby and then gets regressed, it becomes removed.

You don't end up coming out of the womb with

the vulnerable base puts a set of eyes focussed on

it.

So the how do we test that?

Once we've got that detection, how do we how do

we explore that So it rodents and that's voles and

rats and mice.

And one approach is to take the top the two

to the top one is to take that rat, expose

it to another rat to play with.

The two rats will play with each other a bit.

I spent time in a board and run away into

it during sniffing and grooming.

If you put them back together a little bit later,

don't just ignore each other again.

They remember, Oh, it's this right?

But if they're given a new rat again, explore and

extending, you know, sniff each other and greet each other,

and all those things that rats do when they interact.

So you can measure that systematically how much times these

two animals interact with each other and use that as

a measure of social recognition.

So if you were to damage the ability to do

social recognition, a rat can't do that.

We just treat all rats as if they knew they

won't trust, will not know who it's mated with, who

is it's daughters or sons or in terms of rat

pups.

It would just it wouldn't have that ability.

So that's one way to measure it more.

Find ways to use a social discrimination procedure that's been

used extensively in bowls.

So put the test participant in the neutral middle chamber

with door flaps that can run through doorways into other

chambers.

What they'll do is have one.

Another animal on one of these is tethered, is a

little tether around its legs.

They can't escape that chamber.

Just briefly, for the purposes of a short experiment and

another chamber with another one with a little tether.

That's what shown here holding.

It's like they can't get into the middle chamber, an

experiment test whether the devil in the middle will spend

more time with the partner than it's mated with recently

might be.

Or it might be.

It could test lots of things, but typically it might

be a partner that the vole has mated with or

obviously spent a lot of time with to invest the

time with or completely unknown vole that it doesn't know,

or it could just hang out in the middle.

But what this this fascinating work, there's a review we

recommend you read in the reading material and so in

young which really explored all of this work was there

are two two different distinct species that probably more but

two distinct species of vole, a montane voles, a prairie

voles.

There they look almost identical, but they have different genetic

backgrounds and different environments.

Now what you can see is this time spent in

each of the chambers and we've colour coded these.

So the green period is the partner one, the neutral

one is the sort of purple one and the beige

one is the stranger.

So what you can see for Montane Voles is they

don't.

Let this go in the middle is just mated with

this other one, but it would rather spend time on

its own.

It's just going to spend time sitting here grooming, maybe

eating and doing what it wants to do, but it

doesn't really distinguish between the two other goals.

That's not true of prairie voles.

They're less likely than anywhere to be in the neutral

chamber, and they're very late to spend time with a

stranger.

What they spend most that time is with the partner

they've made up with each other.

That's helpful.

So this shows these two different species that look very

similar, have very different social behaviours.

And as you can see in the wild, these, these

variables will mate and the bond and they'll spend time

together and they'll snuggle up.

If I go right back to this early picture.

That's two prairie voles together with their offspring.

And they really co-invest and raise those offspring together.

So that's one way.

So what's different with these these voles?

What's different between montane and prairie voles?

And this review goes into this in a lot of

detail.

And so for this lecture and we've got 40 minutes,

I'm just going to highlight a key takeaway message, and

that is when you look at the brains of Montane

voles and prairie voles is a particular molecule or two

particular molecules that appear to be different.

Oxytocin, the vasopressin, come on to explain those in the

next slide.

So these two molecules are much more abundant.

They have many more receptors in key areas of the

brain for motivation in prairie voles than they do in

montane voles.

So what's going on?

So they discovered this.

What's going on?

Why these molecules?

Well, the next experimental thing is for scientists to do

is let's manipulate that.

What if we were to inject these voles with oxytocin?

What happens if we boost it artificially?

Or what if we knock it out by giving a

drug that stops them working?

A lot of that painstaking work over decades of research,

lots of graphs, statistics, publications, somebody just put it together

in a cartoon slide to explain a lot of billions

of US dollars being spent.

What you're looking at the top is two voles.

And what brought to this picture to me, but they're

mainly work is work is on voles.

And what they'll do is what this thing at the

top is.

Normally this slide would be even clearer, is that typically

the two would be the thing with love with each

other for the diagram.

But the top one, the male profile has been injected

with very suppresses and he hasn't before mating.

So the two the two goals here typically ignore each

other.

In this first instance, they don't know each other that

strangers.

If we go back to that previous slide, this is

this state here.

The stranger doesn't care, the verbal.

But what they've done in this experiment is inject visa

pressing into the male.

Now he keeps trying to snuggle up to the female,

but what does she do?

She runs off.

She doesn't know.

She's not interested in it.

And so that's what this diagram, this this illustration is

sort of looking away.

What is this male sorry to do here?

What if they inject oxytocin into the female?

You get the same effect the other way round.

Now the female is trying to couple up with the

male, but the male is confused and running off.

Normally, if they mated together, they would both show higher

vasopressin oxytocin levels, but they're not.

So this showing that you can boost this bonding process

just by injecting one chemical that turns out to be

very depressing for male voles and oxytocin for female voles.

They're different.

They work slightly different in these two species and humans.

It's a more mixed picture.

It isn't that simple for other animals, but for voles,

it turns out to be these two, this to just

this way.

Right?

So the problem here is that's the period before.

This is about confusing the animals, artificially boosting bonding when

it hasn't happened down at the bottom is saying they

have mated.

Now, these two, those should have enough eyes for each

other and be snuggled up.

And that's indeed what the female is doing after mating

here.

But they've injected an antagonist, a blocker agent pervasive present

in the male and that he's not wanting to couple

up and bond.

So they've turned off his natural inclination to snuggle up

with the female and invest time with her just by

injecting one chemical change this entire behaviour and then they

find they can do the exact same thing with the

female just using oxytocin antagonist.

They've blocked oxytocin after meeting in the female and now

she's sort of in this illustration telling him he's a

loser and he should get lost in this illustration to

highlight what the scientists are inferring because is much more

biological than then.

To this, what's going on?

Let's turn to the anatomy now.

Let's turn to the human brain.

The brain is sitting at this lecture theatre in front

of me.

And so here's a here's a sagittal section through the

human brain.

You can see the pons and the midbrain and so

on.

And if we zoom in on this bit underneath the

corpus callosum, we have the thalamus in the middle here.

Here we have a region of the brain underneath the

thalamus called the hypothalamus, and we learned about it in

lecture last Monday going on stress.

We talked about the anterior pituitary previously as the output

of the stress hormones, a hormone that goes in activates

the adrenal cortical to growth hormone from the anterior.

Now we're going to look at the posterior pituitary.

The anterior is involved in stress.

The posterior is involved in that building process.

So what the scientists discovered, looking at the voles and

then exploring in humans, is that there's a particular nucleus,

the power of ventricular nucleus.

It's very similar in your brain as a mammal to

evolved, very similar.

It just sits next to a bit ventricles.

That's the reason that gets his name.

There's also a super optic nucleus just above the optic

plasma.

That's where it gets its name from.

So these two nuclei have nothing to do with ventricles

or optic fibre optic pathways.

It's just the name comes from where they're located in

the brain, but they're tiny nuclei.

They have more than five cells.

This illustrations obviously schematic, but these are these are the

bodies with cells that act with dendrites and they have

axons, a good tone and an interface onto the blood

cell, the blood, the circulation system, the capillaries.

And they release, as is shown here, oxytocin, invasive breast

and into the bloodstream from the Stewart the posterior pituitary

gland.

So typically this is what's known as neuroendocrine communication.

So here we have our classic sounds of them and

talked about in lecture three about sign ups, this and

the transmitter systems.

You also have endocrine responses in your body where you

have hormones that operate here, like puberty is driven by

our hormones.

Here.

What we're talking about is this other third pathway where

you've got neurones that are connecting into the blood and

releasing.

This is known as neuroendocrine function.

And that's how this this process is occurring.

Now, this slide takes us on the journey from voles

in a lab and injecting them to humans rather than

injecting humans.

They will take a nasal infusion of oxytocin into people's

nose and get it through circulating up into the brain.

And then what they found is that there's a whole

range of different experiments.

But one is that to show that oxytocin changes the

way in which we treat faces, it's been a bit

controversial.

There's, you know, trying to get these expressed.

Replicate can vary because not everyone reacts.

Some people are really good at facial detection and others

not so good.

And these individual differences can be a challenge.

But overall, the evidence weights the oxytocin and upregulate your

ability for social processing.

So detecting people, treating a neutral face is a slightly

more positive game.

Experiments where you have to trust other people to solve

problems apparently are sort of elevated by oxytocin.

But here's an experiment shown here by DOMS without biological

psychiatry where they injected a placebo, so nothing going into

the body or oxytocin or not injected these infusion again.

And you can see, going back to Solomon's lectures, the

amygdala responses to angry faces in the placebo condition is

really high.

There's an emotional response basically to these against the neutral

faces.

But what you see is that this is dampened so

you get less reactivity, too fearful or angry, but in

fact happy faces.

So the whole thing sort of reactivity in the amygdala

is lowered.

That means that you're more likely to approach people, you're

more likely to engage in activities of behaviours.

That bonding process is what's argued by these authors.

And there's a review in 2009 in Frontiers in neuro

and chronology.

So just to take that from a lab experiment, injecting

people in the lab looking at brain scans is a

real world example like I gave in the Fitbit on

Monday.

This is a couple of Nick Fleming and Linda Gaddis,

who had their blood molecules, had their blood circulation taken.

Here's Linda.

Having her blood extracted on her wedding day, consented to

a centrifuge and examined out her wedding alongside her husband,

their parents, for their close friends and various people.

And this is a wedding I actually attended.

So is that what you're going to write it up

for?

The Daily Mail?

So this became known as the cuddle, the cuddle chemical

oxytocin in the study.

And what is this?

This just highlights the kind of thing that would occur.

And this is to give a real life example.

A month later, after the wedding, Linda got an email

from Zach, the research scientist.

And to her delight, the predictions were correct over oxytocin.

Her husband Nick, and her experienced rise in the the

love hormone with the cuddle chemical or oxytocin during the

ceremony and the mother of the bride, the father and

the relatives, they all boosted.

But the friends were more mixed to experience the rise.

But five didn't.

Perhaps they were not feeling the love.

So that's the way the Daily Mail has covered this

kind of research.

And you should be sceptical.

Be careful about overinterpreting.

This is the love molecule.

It's a molecule that is raised and you can see

that that actually does fit the predictions that these these

molecules will rise in a small sample in a very

particular scenario.

But it's a very well studied phenomenon.

The rise in oxytocin relates to social bonding, but it

does more than that.

So there's a really nice article called Oxytocin, the Great

Facilitator of Life.

And we're looking at this period here, social recognition, and

we've been talking about social bonding and mate choice and

feeling of trust and recognising social partners and children involved

in play, but it's also involved in a whole lot

of things that enable, as you can see here, through

sexual behaviour, dampening aggression, potentially unintended childbirth, raising children, tiny

babies through lactation and improper parenting is the mother right

through.

So they've argued this this whole cycle of life or

maintenance as a species is somewhat dependent on oxytocin functioning.

But it's not the only one like oxytocin works with

others.

There's things like serotonin and adrenaline.

To all these molecules you need.

Oxytocin appears to play this great, facilitative process that improves

and enhances all these things.

So that's the first part of the lecture I'm now

going to focus.

I've been talking about the bonding process here.

I'm not going to look at this bit parenting, what

happens in maternal and paternal behaviours.

There's a really great review.

It's quite sure maybe four pages by Dulac and colleagues

in science from 2014 on the Moodle page is also

a short 15 minute video.

The Catherine du Lac is one of the best researchers

in the world on this.

Just talks through the camera about parenting process and what

she's uncovered in her work and various prestigious institutes and

what they've been able to do.

It is absolutely remarkable when we dive into this work.

So what they've shown in this work is that parenting

occurs in a surprisingly large variety of vertebrates and invertebrates

insects, arachnids, molluscs, fish recipients, reptiles, birds and of course,

mammals.

We've been talking about I've been talking about mammals all

the way through here.

But you have beetles that carry around their young.

You have frogs that occur after they're young, you have

birds and of course birds.

And the most classic thing is birds.

They have to look after their nests with their eggs

in it.

They have to pay it.

Young, bring them food when they hatch.

And so so there's a lot of analysis of parenting.

The most common form of parenting is its female unit,

parental.

That means that the female is giving birth to the

young and takes the majority of the role in raising

that young.

The male may lost.

She's responsible and that accounts for that.

And that's, as noted here, to carry the offspring.

She has them.

But there are many species that show this by parental

care.

Birds are amazing.

When 90% of birds are shown in examples here, both

parents are involved in raising the young.

And that's partly to do with the one of them

sitting on the eggs and looking after them.

But the challenge of bringing food in for their offspring

means the birds are particularly, you know, we'll spend a

lot of co-investment.

But that's also true of snakes and reptiles in some

cases.

Then they share this.

But there are also some species of bird important to

be aware of where there's a male unique parents.

Also stickleback fish or a good example.

And seahorses are not shown here, but they show particular

male that the female will lay the eggs, but the

male will then take over the role of raising those

young to the point at which they're they grow up

and become independent.

So it's quite fascinating.

So what's what's the takes on this new lots of

different species here.

But one of the conclusions of studying them in Europe

biologically is that there appear to be across beetles to

the to the stickleback fish through the reptiles and amphibians

here, all the way through birds and mammals at the

top are highly conserved, antagonistic circuits.

What I mean by antagonistic these things don't work together.

They are on or off.

You can't be doing this and that.

They are antagonistic in controlling either the activity of social

bonding, parental behaviour, or aggressive behaviour towards offspring.

And adult animals can display parental care or aggression according

to their physiological state.

Are they ready to do that?

And what is the environment?

So it's a combination of that.

So these are these are statements.

These are course conclusions that come from that review, and

we'll dive into those in a moment.

But it's worth being aware, we live in quite a

civilised vertical society that if you step out of the

door, you're not going to see a huge amount of

aggression, I hope, today.

But I have to go back more than 200 years

and you would see a lot of aggression in humans

and there is a lot of aggression in other parts

of the world.

Very sadly, there are wars going on.

We are quite violent species.

But that's also true of a lot of other mammals

and other species.

There's a lot of fighting for survival out there, and

that requires that fighting and obtaining the the nutrients and

the food and water you need requires aggression.

You have to fight for things, for survival that Lucian

has built into the brain of these mammals and other

other vertebrates.

Aggressive behaviour to survive.

But whether they're aggressive or caring depends on the situation.

So this is a graph from that paper that'll take

a little while to unpack.

So what we can see here and explain the y

axis, first of all, this y axis, and this comes

from a this review.

As I said, here's some quick actions.

If you look at the Y axis is what percentage

of a group of male laboratory mice, these are males

who are virgin as and they're not they're not mated

previously.

And they're previously this is this is a graph after

those male cf1 strain mice have first and they're like

mated.

So they have mated.

They're not going to have offspring.

And what it shows you in the initial period before

or just after that is the natural behaviour.

This is what most male male mice will do, and

this is quite similar to a lot of other rodent

species and other mammals.

Lions, for example, BE The classic example is that most

of the time, given the opportunity, if that mice finds

another unprotected pup in other mice, it will attack it,

it'll destroy it.

It's, it's trying to unless it's a pup, it won't,

it will treat it with attack.

It might ignore it in many cases.

Occasionally it might retrieve that pup.

There might be social circumstances under which it gets activated

to help retrieve that problem.

But you can see just in the spirit this fluctuates

from here.

80% of all the male mice to looking at Habitat,

the men being given this experiment just a few days

after mating.

But then there's a radical shift in these male mice.

His brain.

Something is switching off that aggressive circuit, and it dropped

to 10% of them are attacking and 80% of them

are switching to retrieving pups.

That can't be their own pups because they've just mated.

But it will be other pups they find scattered in

the environment.

And that slowly declines and is a shift after about

60 days.

And the idea is that they're.

Is a rapid a period where they need to avoid

attacking to support the female.

But after that period isn't that they will typically be

left that scenario and they'll be back to their standard

state and switching.

So what we get out of this experiment, is it

really true?

Is it real physiological change induced by that process of

mating?

And so we can see a similar pattern to what's

going on here in wild female mice.

But that doesn't happen in laboratory female mice, intriguingly, that

sort of they've been bred to be a bit more

docile and nicer to pups.

That's what ends up being used in lab experiments.

They're not as aggressive.

So what causes that?

So this is a great grass in Davidson, could be

in the wild watching this and describing it and say,

Wow, look at this.

Amazing behaviour is a remarkable behaviour we can see in

the animal kingdom.

But you're not in nature show.

You're in a neurobiology lecture.

Why?

Why do we get this?

Well, what these scientists have done their research is this

their time dependent?

So in that process, synaptic changes to the sign ups

as there have a changing in those male mice brains

and rest transcriptional.

So that's within the DNA you're having different readout of

the genes is a change in gene expression and triggered

by that mating process.

So that mating process causes the release of different chemical

cues that change that.

And some of them are released by females during pregnancy,

can drive that radical behaviour shift from killing to parenting.

What they found is if you disrupt the verbal maze

Logan in wild male virgin males, it will reduce that

process.

If I go back to that graph here, you took

a mouse, take a group of mice and you disrupt

their vulnerable needs.

Logan They normally would attack, but the ones we don't

have the capacity to detect those cues drop down.

They start behaving as if they mated.

They're no longer detecting the signals that cause them to

attack.

So that formalised logic is not just useful for going,

oh, detecting your friends or your children, but detecting strangers

for the mice.

Why they attacking these pups?

Is it trying to preserve their own particular gene pool

of their own genes?

If they can make the mouse, the male mice can

maybe all the other female mice and it can have

its offspring grow up.

The best thing it can do is kill off the

other competitors children.

And again, there are lots of other mammals that do

this.

Lions or the famous example, it will kill a new

line and just the bride takes it will kill the

the cubs from the other lions.

That happens to be in that pride.

But you also see these going to patterns and berry

burying beetles.

So not just vertebrates and lots of birds.

The changes in the female are more varied.

So you have the well known features to do with

oestrogen.

Progesterone and prolactin are all three hormones that circulate through

the body in females during pregnancy that change that maternal

behaviour in males.

There's also testosterone very familiar culturally with the idea of

testosterone is linked to aggression.

It regulates a lot of that is very high in

the males and it can be reduced in fathers to

produce less aggressive behaviour.

But of course this varies.

I always remember all these things vary between people.

That graph shows you this.

There are some, you know, some animals, some of these

males after after mating, they're still attacking and killing and

there are some before they mated that are not doing

that.

So just be aware.

There's a lot of variation out there too.

Now, I've written on this slide down memory you do

not need for the exam to memorise the layout and

the interconnections of all these nuclei.

That's not what this is about.

This is a this is a figure four from that

really great review.

What you need to take away for this second module

is that there are two of these circuits.

One circuit is involved in parental care and one circuit.

This involves an aggression, so particularly violence towards other strangers

and pups.

And the important point here is that these two circuits

are linked.

You can see the accessory olfactory bulb.

That's the pathway you heard in the slide three where

I talked about the vulnerable days and going to this

area.

And it projects into the aggressive aggression circuit.

And if you damage that that circuit, it won't get

turned on as much.

They're not going to show as much aggression.

The here we have another circuit involved in parental care

that can get switched on.

And instead they have they have these two interacting circuits.

So they will, if one is on the axons from

these brain areas, will terminate.

And a lot of these other is to shut them

down.

They'll be negative impact and vice versa because you can't

be both aggressive parenting at the same time.

That's just because you just can't do the two different

behaviours.

So you notice to you there are a lot of

other brain areas we come across.

We've got here various areas in the amygdala that are

important for Christmas, think parental care and we've got the

prefrontal.

Text.

It's receiving and sending information back in.

And you have again to remind you have a lecture

at the end of the course and what the prefrontal

cortex is doing by Professor Paul Burgess.

So we come back to that.

You can hold on to this for the moment that

the prefrontal cortex, it shows a modulatory control in a

lot of behaviour.

One of them is the the exertion of parental control.

So these two circuits exist and they they're antagonistic.

What do we know about them?

Is that the aversive circuit?

First of all, that that red one is dominant.

It's the one in charge most of the time in

female virgin rats and male virgin rats.

We talked about in lab female rats, mice and rats.

The same sort of idea here that can can be

quite docile.

But generally that aggressive circuit is long.

It will it will lead them to survive more.

The aggression will save them as a as a rodent

post-partum.

So after mating and the desensitisation that occurs with in

females, there's this hormonal neuro modulatory experience dependent factors that

activate that, that other affiliated circuit that also acts to

silence that that that the circuit, the one that does

the aggression and avoidance.

So just to highlight here it does this this is

the avoidance and aggression.

I've mainly talked about fighting, doing things, but this circuit

is also important for just ignoring, running right, just not

caring all these behaviours that again, are part of survival

for for mice and rats.

As part of us walks the toasting we talked about.

That is really key in the initiation of that material

behaviour.

So we talked about if you inject these goals with

oxidation, they won't thorns, but they also won't treat their

children.

They won't do the licking and grooming that we heard

about under the stress lecture.

So it really is important for oxytocin to be to

be to be engaged for that.

There's an area we're going to talk about next week

in the detail of the ventral segmental area.

We spend a lot of time talking about that and

the molecules don't the mean and that's involved.

It's a state just at this point, this brain areas

involved in initiating this process and maintaining the behavioural maternal

behaviour.

So oxytocin is not shown here, but bonds on the

receptors in the ventral segmental area and the ventral segmental

areas you hear next week is the brain area that

motivates and drives animals to do things again and again.

So in this case, the drive here is that the

animal is the, the, the females to really spend time

investing with a the pups and be the partners.

So that brain area is key for drives initiating and

maintaining that behaviour.

We'll come on to how it does that for all

sorts of things.

So people, the things we get involved in are habits,

bad habits, Ferals that driven by this all depends on

the situation.

But beyond that there's also adrenaline and serotonin.

Serotonin.

These circuits are involved in maternal behaviours.

Just to highlight in this picture here you have these

various brain structures showing up here and these are the

areas, the rough and the locus to release these two

brain areas that release that involved in in regulating our

attention, our arousal and our focus.

These here appear to be part of that circuit that's

involved in paternal care.

And so these are also involved in that in that

process.

So just to end on, I'll talk through one experiment

that just gives a really good two experiments.

This one and the next one is a wrap up

today's lecture.

This is a figure from a news and Views article.

So Rodriguez are writing up, trying to explain this experiment.

But another group had done so.

What they did in this experiment to understand the maternal

paternal process for male and female is what's happening in

their brains.

And in this case they're looking at the medial pre

optic area of the hypothalamus.

So earlier on in this lecture, I showed you the

hypothalamus and I explained this like a number of different

nuclei within there.

One of these is called the medial pre optic area.

It's got nothing to do with optics.

It just happens to be next to the optic nerve.

So the medial pre optic area and after the animals

have mated, you tend to get activation of neurones in

this brain area.

They're not as active before, but they become activated after

mating this small bit of brain area.

And that's what's indicated here by the red neurones.

These are neurones that are sending out the highly active,

the sending out transmission, That transmission of those neurones of

the medial pre optic area they're arguing is driving that

parental behaviour.

And the reason they're finding these are critical is that

they can go in and they can deplete those neurones

just in that one tiny area.

You barely see it in the brain.

They've gone in and selectively damage those neurones by clever

chemical techniques.

But after that process you get no parental behaviour from

the female or the male remaining looking at female mice

and experienced male mice and experienced female mice.

Like I mentioned, it's the virgin males where you don't

get this pattern right.

These all show this, this.

If you damage this, you don't get this parental type

behaviours.

So that's the grooming, the retrieving pups and taking care

of them.

Okay, that's, that's one experiment to show it's important.

That's one way of doing it.

But ask these these four groups, virgin females, experienced males

who mated and experienced females and mated experience here is

little about mating on the right hand side.

Now, this is for me.

This is why this paper was published in science.

That first experiments.

Okay.

It damaged the brain.

They can't do it.

That's fine.

Very long.

Here is the kicker.

Experiment around.

From a scientific perspective, it was virgin male mice.

First of all, you can see they're not active.

These cells that are active in these all three other

categories of mice in the virgin males, they've not mated.

They're just like young, aggressive male mice who have not

made it yet.

And what do they show?

Aggression.

They attack.

They tap upset.

They get rid of them.

Here's what they did.

They went in and artificially using optogenetics, find those cells

that could be activated, activating and activate those cells by

shining the laser light onto the genetically tagged cells.

So what you can see is before and after that

light is this this is a couple of milliseconds.

You've got a normal functioning male.

You shine a light.

2 milliseconds later, a whole of the cells are turned

on.

What does it do?

So rather than running across the cage and attacking and

possibly trying to bite and destroy pop, it runs over,

it picks it up, puts it back in the nest.

So by just turning on a light, affecting a small

number of cells, more than the number of neurones in

this illustration here, but still you're talking about tiny cell

nucleus in a small part of the brain.

You switched one animal from showing this aggressive behaviour to

a whole different approach.

And it's really worth what's quite amazing about this is

it's not like you've improved motor function or its ability

to perceive light in some way.

You've changed the radical feature of its entire behaviour in

a millisecond.

You've with this experiment, they've turned to mice that would

attack and kill.

It's one artificially thinks it's mated effectively.

It's not thinking about this, but you've artificially activated a

parental circuit in an animal that's never undergone any change.

So this shows the power of the kind of optogenetics

approach of exploring behaviour.

So you got to ask, why did you use the

light?

How do you see through this activity?

Yes.

So optogenetics, as you heard in your lecture on the

methods lecture, remember that the methods, the techniques you learned

about what you could do is genetically tagged those cells

in these particular rats.

I think it is for mice in mice more likely

get mice.

They've gone and bred these animals with specific proteins that

are sensitive to the wavelengths of light.

When those wavelengths of light are show shot, shine down

on those cells through a cut in the top of

the brain of the rat, the mouse, they can artificially

turn them on and they can do it within a

couple of milliseconds.

And so you can have a rat, a mouse running

across the cage to attack and switch the behaviour in

an instant from attack to being attacking an aggressive and

killing to being attacked in milliseconds through one circuit interruption.

So what does that what makes that amazing is that

it's quite a complex behaviour you're looking at.

Now this is a experiment where they were looking at

another particular nucleus.

The this particular part, the AVP haven't read that, but

it's in this paper.

So this is a hypothalamic nucleus which differs between Virgin.

So a difference between males and females in virgins.

But what they showed is that this particular is not

just the nucleus involved with the particular subcategories of neurones

that can start to get to that.

You can regulate in the parents, the females.

So males after mating don't show a change here, but

the female mice can show a change in the number

of active neurones in this particular nucleus after mating.

So not only do you get these patterns of expression,

but you can get them in particular male or female

situations as well.

But it's worth going to watch these movies to see

the patterns of behaviour.

So in this link, if you don't follow it through,

you will see the use of optogenetics where you get

mice, which is not really fighting with each other, and

then they'll turn on these these neurones artificially and they

can do it in males as well.

So they can turn on the mouse.

Yes.

This is almost certain case.

Oh, yes.

But this is all about.

So if they might be right, they might not get

children from mice.

It's extremely likely their breeding capacity is way higher.

That's one of the reasons they've ended up being laboratory

animals that are really higher breeding.

They require fast turnover.

They can have children very quickly, but very likely they

would, but it's not dependent.

So these activation patterns are not dependent on the sex

success.

Well, I think you would need to activate pregnancy, though,

so if they don't end up being pregnant.

But I think the idea of the meeting alone will

activate patterns of change in the male, because they can't

detect that necessarily.

But to pick up on that point, when the female

does become pregnant, her pheromones secretions, what she's secreting, will

change.

And that provides a cue because humans, we don't really

dissect these things but might do dogs do.

They can detect other animals can smell these things.

We can't in the same way those they go and

watch these movies because you can see them turning off

again with the optogenetics and the midpoints to attack, making

an animal docile and parent and pick up a tree

pups.

It's it's really one of the most dramatic pieces of

evidence I've seen.

And again, one of the reasons it's published in the

most prestigious journal in the world in Nature.

So to wrap up today, there's a nice section in

the physiology of behaviour that calls in or brisket on

social bonding.

That review is really clear and really nice to read

into and Young.

I talked about the voles again, extremely easy to read

article and then there's some other reading.

If you're really interested you could look into This is

not essential, but we can go into that and we'll

see you next week.

The consciousness and motivation, why we do the things we

do.