PSYC23 Lecture 11 – 03-29-12
We’ve got these two different brain stem nuclei and its not clear how we measure them, it’s not clear
why having a lot of this smarter vagus is such a good thing, what it means when at rest vs challenge,
hitting that last point; it’s your potential that’s really noted with regard to the vagus. Having a lot of
vagal activity when you’re resting; a model in your mind could be you know how you feel when you have
$ in the savings account. If you got a lot of these we playfully call vagal dollars, we can withdraw that. If
you’re in a challenge you want to be able to withdraw and spend these vagal dollars. If someone comes
up to the soldier security guard there, he can withdraw from vagus and do something about the person
who is disrupting him.
Vagal Decisions/Vagal Gears (Unconscious)
Do some people make a decision of having low vagus, or having new vagus activity or maybe having the
old vagus activity? Species differ; mammal vs. reptile, and which vagal system they will be using,
associated with behavioural strategies. People are different in terms of temperament. When people are
challenged, they let go of that brake in the PNS. You withdraw, and the sympathetic system kicks in.
Captain Kirk; that smart use of vagus is associated with him. When he gets excited, his vagus withdraws.
There are people speaking of individual differences who just don’t have enough vagal activity. People
who are depressed have really low vagal activity. If they can stimulate the vagus nerve artificially, that
can sometimes help them.
Quantifying Smarter (Newer) Vagal Activity
How do we differentiate; vagus activated by new vs old vagus. We can’t really measure this directly. We
know that the vagal fibres are these thick cranial fibres coming out of the head to targeted organs in th
body. Some of them are attaching to the heart. Strategies adopted these days; when you breathe out
and sigh; there’s a surge in vagal nerve activation. Your vagal system is highly activated when you do
that. When you do breathe out, we know that your heart slows way down breath to breath. The longer
you breathe out, the slower your heart rate; when you panic, heart rate sky rockets. Indirect measure of
the smarter vagus and not older vagus is the way to go.
Vagal Behaviour Links
Last week we ended with this figure/table of all these different studies by providing definitions of what
these terms are.
With a baby when they are sucking, they do vagal withdrawal. Nipple in mouth, focus on that, smart
vagus will withdraw. That temporarily causes the heart rate to speed up. The car is a good analogy. If
you didn’t have that smart vagus, heart rate will be 100 times faster. This system keeps your heart rate
at a pace. That allows us to do in the emergency to take our left foot off that brake and zoom ahead.
That’s an important point. The babies are taking the foot off the brake and sucking and metabolize. You
get aroused and relax a little bit. You go into a calmer state. Now there is this issue of resting. When you
are sitting down resting and your ability to lift up that vagal brake when there is a challenge, both things
very good, having a lot dollars in vagal bank and lifting the foot off the brake when met with a challenge
is very good. The ones who show those heart rate changes are ones who do the best. Crying and just
observing someone being emotional; the vagus was going in opposite direction. Crying and sobbing; you
know what it is like to cry; breathe out more deeply. For that reason they just found that u increase your
smart vagus in the act of crying; vagus activity increases. In contrast if you just see someone being really
sad it’s kind of disturbing maybe and a challenge for the vagal system. You respond by decreasing; taking
foot off the vagus nerve. So again this sadness thing is kind of like a challenge and consistent with that.
When you are just crying and sobbing and initially in the first couple of seconds, suppress; but you will
rebound. Memory is the same thing.
Unit 3: Memory
Four pictures slide
Left top picture is Aristotle; there were other people from his time who had similar ideas. It was a way
like having an experience that has an impression on your soul not unlike a seal makes an impression on a
ball of wax. You heat the wax, sit for couple of seconds, and then stamp it. In the heated stance, it will
be whatever you want it to be then it hardens. To what extent is that really the case that memory is
simply the outcome of this impression making system and that once you get the wax to harden then it is
all over; you got a nice harden memory that is permanent.
The second this A rose was what is the difference of having one of these perceptions that will become
memory? What is the difference between the perception of Haley standing there and the memory of
that? He made the point that you really can’t make that distinction. The ability to distinguish what you
perceive at the moment and a lasting memory; you just can’t distinguish that. And what’s a little bit
edgy is that we are getting data showing that the perception is part of your memory. The parts of your
brain that perceive what is in front of you are activated when you recall that.
For the brain remembering is like reliving
The temporal lobe, the hippocampus is important for encoding and consolidating on. You can put
electrodes deep inside the brain in one study, it’s a surgery. Record single neurons deep inside the
medial temporal lobe and measure hundreds of them simultaneously and show brief stimuli and
measure how much activity they get out of neurons; that are the perception part. A few minutes or days
later, they just ask the subject (they aren’t unconscious or anything) to recall the videos they had seen
previously. The result is simple; the same part of the brain that got excited when they watched the video
also became excited and fired during the recall of the same thing. So it’s the first time that people could
say some part of the brain is firing when you perceiving and recalling something. That deflates the
distinction between the differentiations.
It’s a process, it’s not that you just take a picture that your memory is forming pictures; you have this
unfolding process of this perception where you overtime form this image to form that initial perception
but it does take a while; this is what we call consolidation. Initial memories when they first form are very
plastic and not until that the consolidation occurs that you get this harden result and this lasting
impression, your soul is filled with the lasting image.
System consolidation means that because we know the importance of the hippocampus in memory, it’s
when you go from this initial timepoint of forming this memory to a later timepoint where you no longer
rely on the hippocampus. You have moved from a dependent to independent hippocampus memory.
The other kind of consolidation is more interesting. It’s literally the act of making your synapses alter in
some way to represent that new information. How do you think the memory goes from a perception to
something you can recall later on? It’s possible that the neurons themselves are changing in some way.
Something is getting reorganized in a cellular level in response to this harden memory which becomes
long lasting; that is cellular/synaptic consolidation. If you have a new memory let’s say the word bear,
you got that in your working memory right now, something synaptic is changing right now that is
synaptic consolidation. If we inject something that will block your synapses like electric shock, you won’t
be able to recall those perceptions. We also know that if I said the word bear and immediately said
giraffe and a number of other things it will get harder and harder to remember the initial word. Again
pointing to the fact that too much information overload will kill you, it’s like Tetris. Once you learn
something and then you ingest some stimulant like coffee or cortisol, it’s all good; it could enhance your
memory initially. Cortisol can get directly into the neuron and to the nucleus and affect the way the DNA
is behaving. That’s a big deal because if you get stressed out among the many different things cortisol
can do, one of them is getting to the brain and the neuron and stimulate the cell by activating genes in
the center of that cell, the behaviour of that gene determines the proteins to be made. Depending how
it is activated or stimulated that is how the proteins will be made.
Stress receptors and memory
Cortisol receptors are literally the most densely populated in the hippocampus because it means that
cortisol is no matter what is going toward the hippocampus and there are receptors there waiting to
take in the cortisol.
Emotional Memory and Sex Differences.
There is some evidence that men and women differ of which part is remembered in that bear/cougar
video we just saw. Women are more at risk in developing symptoms of anxiety and depression.
Sex differences in emotional memory consolidation
Do women remember negative images more? You bring men and women in and show them the images,
you then subject them to a stress or nonstress condition. You want to manipulate how stressed out they
are. You literally plunge their arm into ice cold water or you put their arm in nice warm water. They
were randomly assigned to two of these conditions. And males who were assigned to the cold stress
condition and the females who were assigned to the cold stress conditions both showed elevated