Newborns and reflexes

[Auto-generated transcript. Edits may have been applied for clarity.]

Okay. Sorry people, I'm having technical difficulties, but hopefully we'll be okay.

Um, so y'all remember that I got almost to the end last week, but not quite.

So, um. Oh, so I'm starting today by finishing up a bit about, um, what can foetuses learn before birth?

Um, so I'll talk a little bit about that. And then I'm moving on to the newborn baby.

And I'm hoping I'm going to be able to use PowerPoint, but we'll see.

Um. So these little kiddos, what happens here is that we are looking at, um, if there's if there's any signs, right.

You can't ask a baby. So before you were born, uh, do you remember, um, having the cat in the hat read to you?

Uh, but we can look at behavioural differences between, um, babies who, during pregnancy had this training of having, um,

Cat in the hat read to them twice a day, um, versus, uh, versus babies who did not have that exposure during pregnancy.

Um, so here they then test at two and a half days after birth.

Um, wire up this cute, cute little baby.

And, um, the babies then would hear this cat in the hat story.

And for some of them, it was familiar.

And for some of them it wasn't.

And those who heard this familiar story, they, um, sucked faster on the dummy, um, than the sort of than the control babies.

So that is a behavioural difference which demonstrates, um, at least familiarity.

Right? Which means that they are recognising something from their past life, uh, in the womb.

Um, and this is just the, um, uh, that this is just this is another example of a study which, um, demonstrated the same thing this time.

They had the neighbours theme tune played, um, during pregnancy.

And again, they then saw differences, uh, between the learning group, those who'd been exposed to the to the neighbour song.

Should we have a better neighbour? So the babies who had learned the neighbours theme tune, um, did indeed behave differently, right?

They were like, they're less moving around. They're like, oh I know this.

Mhm. Um, so these are the sorts of things, uh, that the sorts of ways with newborns that,

that we have to, um, uh, try and gauge, uh, whether or not something is familiar to them.

So this is you can imagine it was it's all this kind of stuff which got people which, um, led to, uh, all of that commercialisation.

Right. The Einstein babies thing and, and, um, luckily, I don't think it's so popular anymore because it seemed like daylight robbery to me.

Um, people, uh, um, you know, selling selling would be parents, um, recordings that that they could play to their,

to, to the womb, uh, and then that, that their kid would end up smarter, um, in the long run, you know?

Spoiler alert. Don't waste your money. Um, but if you want them to recognise some of your favourite shows, it's possible.

Okay. References for that.

And this is where I get nervous. So here's our little newborn baby, which we're now moving on to.

And let's see, am I going to have any luck at all?

I think that's to open. SPC downloads.

Oh. Yeah, okay.

Is it opening on your own laptops? Yes.

Yes. Okay. And it opened for me in my office.

So it's something to do with this. So not ideal, but I am going to presume.

I'm going to hope that you're all sitting there, um, and that you can and that you're able to open the newborn baby.

Um, PowerPoint. And I'll talk as though there's the correct slides behind it.

Before I do that, though, I also I wanted to point something out.

Um, you will see that. And now I'm really glad I did this.

Now that I'm having this malfunction here. Um.

You'll see that I asked, um, for Dave Levin's old lectures to to be put on to this year's canvas site.

Um, because I think that his presentation style, his expertise, his sense of humour is, is pretty fantastic.

And what a nice way to revise.

You can, um, you can listen back, uh, to me delivering these lectures, but then you can also, um, get the lectures, uh, as delivered by Dave.

And you'll notice that what I've done is to simplify.

I've, I've cut some stuff out. So certainly your assessment will only be, um, covering, uh, the slides, the content that I'm covering.

And he, he does cover a bit more. Um, but it is really interesting.

Uh, he is very much his expertise is in primates and evolutionary psychology.

So he gives you quite a lot more, um, of that background.

Okay. I'm really glad I printed out my slides.

So now if you could open up the newborn baby.

So again. Materials by Dave Levins, presented by me.

If anybody doesn't have a computer, it looks like just about all of you do.

And if you don't, hopefully you print it out. Or you can look at a neighbour since everybody okay.

That's. It's not ideal. Okay. So the first thing I'm going to talk about is the sensory capabilities of newborns.

Uh, and so doctors will we'll see some of the tests that are commonly done on newborns.

Um, and some of the research done on newborns, which shows that indeed newborns are capable of feeling pain, um, feeling pressure.

Um, proprioception, I think, is worth defining.

That's that sense of your own body.

Um, in in the world, your own sense of your movement, um, and your body position.

Um, and I talked about it very briefly last time about, um, how even in the womb foetuses, um, are that they do sense sort of gravitational force.

Uh, and and that just and that's and that sensibility, um, is also there at birth and, you know,

becoming, uh, more pronounced and also sensitive to temperature, cold and cold and heat.

Um, and again, this part of this proprioception, they do have, um, a sense of, uh, balance.

And, and we'll see that coming through in some of the, um, Brazelton testing videos in a minute.

Um, they also have sensitivities to different smells that that's what the picture is.

Um, there uh, to and and different tastes.

Um, I think I mentioned last time again that the hearing of foetuses and the hearing of newborn babies, they don't have the full range that we have.

It's much more, um, restricted at first, um, and really tuned in to the typical frequency of, um, the human voice.

Um, and that improves steadily over the first seven years, uh, of life.

Um, vision, you may be aware, is, um, not great.

Uh, with newborns, it's it's really fuzzy.

So for those of us who are short sighted, um, that's very much what baby vision looks like.

It's about 2400 at birth. So what does that mean?

That means that, um. What what a what?

Someone with with good typical vision can see at 400ft.

Um, a newborn can't see a well until 20ft away.

So they are very, um, short sighted.

And again, we get improvement there, um, over the first six months of life.

But even so. So there's some some pictures there on the right hand side of the slide.

And the middle pictures are that fuzzy, um, newborn, what they see of a human face.

You can see even though it's fuzzy, they can still see things like, um, I gaze.

Um, and that that nearsightedness does mean that, um, you know,

a babe in arms is able to see their mother, their mothers, or their caregivers face pretty well.

Okay. So what about.

Oh, it's really weird. Very unsatisfactory.

Thank you for rolling with it. Um, what about, uh, neonatal behavioural repertoires?

In other words, when a, um, when a baby is first born, you know, what can they do?

How can they move? What what what are the what are some reflexes that are in place?

So for one thing, they can orient to, um, like, things like faces and, um, they can track, uh, especially human voices.

Um, and then there are different reflexes.

And the reason why there's that big, um, that big yellow vestigial is, um,

to remind it was it's really to remind Dave Levins that his vocabulary is not typical.

I don't know about you, but I had to look up appropriate proprioception.

Um, I might have also had to look up vestigial.

Um, and what does vestigial mean? It means, um, that these are these reflexes appear to be like evolutionary holdovers.

Okay. So they're not necessarily, um, something that we need that is functional in today's environment,

in today's context, or perhaps ever for human babies, but they're sort of this they're that they're leftovers.

They're holdovers. And they reflect, um, our evolutionary ancestors, um, living in trees,

having mothers with fur things and environment situations for newborns where grasping um is, is super important, that clinging is super important.

Palmer is a hand grasp planter's foot grasp, right?

If you're in the trees, you want to use both your hands and feet to cling on.

Um, and also that the moral grasp is, you know, if you kind of let go of a baby, they, they go out and then they grab in.

And that's really useful for grabbing onto, uh, grabbing onto mother.

But it works a lot better if she's furry. And, um, and human mothers are not so furry as, um, uh, some of our evolutionary, um, primate ancestors.

So that's why these are known as vestigial reflexes.

They are holdovers from our evolutionary, um, past.

So some other reflexes so related. And this is sweet Davis and Dave has been in this country as long as I have.

Um, but he still says related to nursing he means breast feeding, um, rooting and sucking.

So rooting is is when you stroke, um, a baby's cheek, they'll orient towards it.

Um. And sucking. So these are these reflexes in newborns to help the mother infant dyad in, um, the task of breastfeeding.

Um, and then related to moving, some crawling, some stepping,

and some of those newborn reflexes are actually way more mature in term in terms of their motor development.

Um, at birth, then they die out, they disappear.

So most of these reflexes will disappear quite soon after birth.

Um, and then, you know, kind of proper, um, proper crawling, proper walking, um, develop, uh, later.

And you'll hear more about motor development later this week.

Uh, from Jessica Horst. Okay.

So. Let's get to the fun part.

And this part should work. So neonatal reflexes.

These are, um, these different, these different, uh, reflexes.

Uh, I'm going to show you. Pray for me.

Uh, so here's the first one. Um. And what?

Why? Why are we watching, um, Brazelton.

These all of these old, uh, videos in 2024?

Because Princeton doctor Terry Brazelton, um,

he was the one who created this sort of battery of tests for newborn babies to test their neural, behavioural, um, you know, integrity.

You know, how how healthy, um, how fully developed, uh, our babies at at birth.

These are a series of of tests which, um, are known as the Brazelton, uh, to to test newborns.

Here we go. Babinski and the grass.

Each foot is tested individually for three different reflexes.

The grass but the toes. Verbinski and for ankle closeness.

For the Babinski, you have to stroke the outside of the foot for the grasp.

You bring your finger in on the midline of the foot and closeness.

You break the tone at the knee and then snap the foot into the leg.

Then I start with muscle tone and try to stretch out each extremity and let it snap back to see if there's any imbalance between extensor and flexor.

Aren't babies just the cutest. Nicholas.

Oh, really? Yeah. That okay?

Oh, there we go. Hand grasped with my thumbs and then pull him up to sit in this procedure.

I'm testing the town and his neck muscles, and then I try to see how much he can ride his own head.

I do it a second time because he has so much tone as he comes up that I really expected him to hold his head

in the upright position more than he did this time he does about the same thing he did the first time.

I say, I wouldn't have been thrilled when, you know, to have one of my newborn babies just being like that.

Um, sure. I'm sure the doctor knew what he was doing.

Then I testing for a walk reflex and for standing.

I placed him in a standing position so he gets both feet on the bed and then try to get alternating back and forth movements of each leg.

I'm also testing him for muscle tone of his lower extremities in the standing position.

I put him across my hand. You think he's sort of manhandling?

Wait for the sign.

Well, testing for a mirror reflex by dropping his head and seeing if he throws out his arms and brings him across his belly in a reflection response.

Oh. Now I'm cuddling next to my body and see not only if he cuddles into my body and twists his whole body up into mine,

but whether he comes down and puts his hand in his mouth as this baby does.

I have to say that I find the most amazing reflex.

The the crawling.

You can you'll you'll sometimes see videos of babies who are just born, um, just sort of crawl, crawl up their mum to get to get to the breast.

And you're like, how the heck did that happen? Um, and then, you know, they can't they can't do it later until much, much later.

But immediately at birth, um, many do show this crawling reflex.

And all of that response, using the rattle on one side and then the other.

He turns his head to it and looks bright eyed, and then I want to see if [INAUDIBLE] follow the visual as well as the auditory rattle.

And so indeed he does, putting real effort into this job of following back and forth.

Cutting down on other movements that might interfere.

You know, attempt to try to get him to look in my face and follow me.

And as you can see, he has a bright eyed look in his eyes widen as he follows.

I had to keep engaging him over and over to keep him coming.

Okay. Then, as I mentioned, um. Uh, well, two things that Dave Levins is very much, uh, um, uh, an expert in primates.

Um, and likes to remind us all that it's not that human babies are related, um, as a species to primates, human babies, all of us.

We are primates. Um, and, uh, as as I mentioned, a lot of these, neo, a lot of these reflexes, um, are vestigial.

And so we see them, um, as well in, um, in many primates and sometimes, um, in a more pronounced, uh, fashion.

Oh. We're far from a perfect mirror image, but just how close are we?

This is Merlin, the 12 day old chimpanzee. His natural mother has abandoned him, so he's being fostered by one of us.

A newborn chimp is very like a human baby. In his first weeks, Merlin shows all reflexes so familiar to a human.

He gazes into his foster parents eyes just as her own childhood in.

He responds to her smile. In chimp and human alike.

These exchanges cement the bonds of love that will keep mother and infant together through a long childhood.

You know. He reacts to the sound of my voice.

Sweetheart, how do you go fast? Oh, offer a baby human or something to hold it and both grasp it with fingers and with toes.

To protect. Go check.

Hold up. Right. Merlin goes through the motions of walking just like a human.

Here comes the big boy. Well, he almost had it.

And this really was that big boy.

Can you come find me? Lay them down and both clutch at the air.

A legacy of the need to cling to our mother's farm. That was obviously also the moral reflex.

It doesn't look any kinder. Um. Uh, with a monkey than that.

Than a human baby. Okay. Um.

Sorry, I have to go back to to not non-existent slides behind me now.

Um, but keeping on the neonatal reflexes.

Slide. So you saw a lot of, uh, examples of those, um, some sketch drawings there of the Palmer grasp and the planter with the with the feet.

Uh, and then I just wanted to mention the picture of the child at the top, in the middle.

At the top. This is an Anand Anand.

So. And it's a phallic child.

What that means is that this child's brain did not develop properly in the womb.

Um, very, very, very rare. Uh, but it does happen.

And these infants don't survive, um, very long after birth.

Just a matter of hours or days. Um, but one what's being shown here is the sucking, um, reflex.

So many of these reflexes are present even.

Um, even among these children who are born with very, very little, um, uh, very little brain capacity.

And what that shows, what that demonstrates is that these reflexes are really lower brain stem, um, activity, uh, which,

which is also, um, a reason why they, um, why we share, um, many of our, our reflexes with, um, our evolutionary ancestors.

Okay. Um, moving on to the next slide about postnatal brain growth.

So one thing is, one thing to note is that most of the neurones that we're ever going to have are present, um, at birth.

Um, and. However, uh, our brain, our brain volume, our brain mass, um,

increases very dramatically, uh, across development, especially across early development.

And that is due to glia.

Okay. So it's kind of like all of the support structures, the maintenance, um, all of the insulation,

uh, that neuronal axons require, all of that is bulking up, um, in early development.

And perhaps the most crucial part is my myelination.

So on the next slide, you'll see sort of reminders from your from your psychobiology days of,

um, a neurone and the axon and myelination is, um, that coating, uh, on the axon.

And why is that important? That's important because that fatty sheath means that, uh, that, um,

information then can be transmitted at 10 to 100m/s instead of only one metre per second.

So it's all about connecting, um, all of our existing neurones.

It's all about that communication being built up, being being developed very, very rapidly through the first, especially the first year of life.

But but the first few, um, years of life.

Um, and a lot of what is happening and is dependent on the environment, uh, in which a child or infant is, is growing up in.

Um, a lot of that is synaptic genesis.

In other words, the forming of these connections between neurones facilitated by this myelination.

And that's, um, the main aspect of brain development, uh, that that's happening after birth.

So that is very much a an interaction between the unfolding of that biological maturation.

You know, yes, there is sort of a, a roadmap, a blueprint, um, in our genetic material.

But the way in which that plays out is an interaction between that biological maturation and,

um, the environmental context, uh, of of, uh, of, uh, human baby.

Um, and to give you an idea about this violent nation in particular and how important it is after birth.

Um, there's that picture of myelination of the brain and the lighter, um, colours.

Those are the areas of the cortical surface that are not yet myelinated at birth.

There's lots and lots of growing to be done. And if we think about human, human babies, um, versus chimpanzees versus other primates, it's one of it.

It's something that is very, very, um, different, very special about human babies that our brains grow far more after birth.

Um, than to other primates.

Um. On the next slide, which is about that synaptic genesis that shows you that that shows, um, the.

The growth of new synaptic connections between neurones.

And it shows you that. It shows you just just how rapid that growth is in early life, and also that it is fastest for the visual cortex.

We get a peak at about, um, 12 months.

Whereas for the auditory and prefrontal cortex we get um, uh, we get a peak at about age three years.

So why is this important? These, these peaks of, um, synaptic genesis give an indication of what what times in, um,

development might be particularly crucial for a typical for a typically developing brain.

Um, so you may you probably will have come across the terms before of either critical periods,

um, for development or sensitive periods, um, for development.

And that's certainly the case in brain development.

So the idea of like a critical period is if it, if if an appropriate environmental input is not present during a specific,

um, time in life, you can't make it up later, right?

There's going to be some permanent brain, um, damage or differences in brain development.

Um.

I'm pretty sure that last year you will have had or and probably those of you who did A-level, you will have you will have heard of seen videos of,

um, Harry Harlow's monkey studies depriving monkeys of their from their mothers and instead, um, they had wire mothers and yeah, horrendous.

Um, and uh, and, and that is an example of an experimental study of, um, you know, severe neglect.

And then researchers Harry Harlow, in this case, looking to see what are the behavioural outcomes of such deprivation.

Um, and we can also and, and other scientists have also looked at then.

The effects of deprivation, um, on um, aspects of in particular brain development.

So. Have you heard of?

What are they called? I can't remember now. Um. The cat guys?

Yeah. Hubel, Hubel and Wiesel, have you covered?

Did you cover that in psychobiology? Yes you did.

Okay, good. So it's just it's just review. And so it's just the idea here.

This was that I mean, it's hideous. Right?

This is where they, they sewed shut some um, that I can't remember if it's the right or the left eye of a bunch of newborn kittens.

Do you remember this? Yeah, I know, horrible.

Um, and the point of the of, of the research is that if that I wish was sewn shut during the critical period of these cats visual development,

then, um, that then the neurones never, um, sensed input in, um, from that right eye.

Right. So they missed out on that critical, um, visual input.

And then it didn't matter that the, you know, that the eyes released, there's nothing sort of biologically wrong with this eye,

but because the brain that, um, visual system had developed without that input, uh, it was it was it was lost forever.

And we see, you know, far less, far less dramatic, um, horrendous examples of this, uh, especially in language development.

Right. So there are certain vowel vowel sounds that I cannot say.

I just can't. You Brits, you got me.

Um, or if you, if you think about, um, a someone with a French accent, we now have, um, a new dean of sciences at Sussex.

Um, he is Luc and he is French, and, um, and if you ask him to say then they went to the pub, he will say, then they went to the pub.

Right. Um, because, uh, he sort of because there's this sensitive period where you learn to make specific, um, language sounds.

And if you missed that, it's really, really hard to learn, um, to learn those sounds.

As an adult, my ex-wife had the name Sean s I an Sean?

I could say that just about if I didn't think about it too much.

Then you have another name in this country. A typically male name association.

Americans pronounce that sham.

It was very confusing for me.

Um, and so I would I practised over and over and over again, and I think I can do it now, but it still sounds weird to me.

Sean. Right, something I have. It's really hard.

Um, okay, I digress. But these things, you know, we see we see young children and it's amazing how they can acquire.

Um, a second, a third language.

Um, uh, you know, uh, when they're three, four years old in a much, much more natural way, um, than than their parents can.

Um. Okay. So that's just talking a little bit about, um.

Uh, critical and sensitive periods in brain development.

Obviously, we don't do any kind of experimental studies on human babies, but sometimes, um,

unfortunately, we have access to quasi experimental evidence of the, um, effects of neglect.

And so. One of the one one way in which we we have a naturally occurring, uh uh, um, environmental insult, if you like.

Uh, it's babies born with cataracts.

Those. So neglect isn't the right word for this one.

But because of cataracts. Right. Which usually develop in much older, um, individuals.

If a baby is born with cataracts and they're not operated on.

They never they cannot learn to see properly.

Um, if the surgery isn't done by age seven.

Right. So you need visual input early in life in order for, um, your visual system to develop properly for all of those neurones to, to connect.

Um, and, uh. Function properly.

The best time to have your cataracts removed is three months or less.

Okay, so and then you get, you get a real kind of, um, between three months and seven years.

It's like the closer to three months those cataracts are removed, the better the child's vision will develop.

And once you get to age seven, that's what we mean about it being like a critical period.

It's there if if that um, if that child hasn't received that normal visual input, uh,

then they're not going to develop, um, develop, ever develop it in, in typical way.

Okay. And in cases of extreme neglect, you'll see on the slide on the second to last slide,

I believe of three year or of of a of three year old children and the one on the left being a normal brain.

And so you can see in a, in a case of extreme neglect.

And this was a, you know, almost total social, um, sensory deprivation that then,

um, the three year old child's, um, brain volume, brain mass is much, much smaller.

Um. Uh, yeah, that just a very obvious sign that, um, the environment can change, uh, biological structures.

So again, it's the interaction between biological maturation and environmental input.

Um, and just one other thing. I'll, uh, I'll, I'll say before the.

Well, no. And then our, our final slide is again, um.

A real visual, uh, a real visual indicator of how neglect affects brain development.

Um, you may be familiar with, um, the.

Romanian orphanages. These came to light in the in the 1990s.

There was really pretty severe neglect of, uh, of these children.

And, um, this is a Pet scan showing you, um, a typical, uh,

typically developing nine year old on the left and then a same age Romanian orphan on the right, um, showing.

A big reduction in their, um, brain activity.

And that, again, was not something that could be recovered.

That's that there's permanent, um, brain damage there.

Before I let you go, I just want to underline one thing that.

One of the fashion and aspects of the Romanian orphans, which is also fascinating,

is that, um, the effect, the effects of this deprivation were not universal.

There was lots of individual variation. So some of these children were relatively it seemed to be relatively resilient to this neglect,

whereas other children, um, were very severely affected.

And that sort of reminds us that, um, development is this very complex interplay between genetic input,

biological maturation on the one hand, and environmental, um, input on the other.

We need both. Um, but the results are the results in phenotype, in observed behaviour.

Um, are really, really very variable. Okay.

Thank you for your patience with our technical difficulties today.

I get I'm seeing you again this time next week.

Um, and I'll. I'll get someone to come and help the old lady.

Have a good week.