Neuro: 10:00 - 11:00 Scribe: Kristina Hixson

Neuro: 10:00 - 11:00 Scribe: Kristina Hixson

Friday, February 19, 2010

Dr. Wyss Learning and Memory Page 1 of 8

I.  Introduction [S1]:

a.  What we are going to talk about today is learning and memory again but now instead of taking a microview again we are going to take the 35,000 ft view and look down on the gross structures that are involved in learning and memory and how we got to an understanding of what areas control learning and memories and how processing takes place. Again it is a little more global level within the individual.

II.  Chart [S2]

a.  The first task I have for you though is to take 30 seconds and memorize this table. There will be test over it later, if you ARS were working. Ok we won’t put this on a board test, but anyways.

III.  Definitions [S3]

a.  Alright so first off we need some definitions of what learning and memory is. Some of this you’ve had already. Learning is an adaptive change in behavior brought about by experience and involving a CNS neuronal mechanism, plastic changes occur all throughout the body, through the nervous system and other systems, immune system for instance. We don’t normally term that as learning.

b.  Memory is the storage of information so they can be recalled at later times

IV.  Terminology of Learning [S4]

a.  Little bit of terminology here. We break down types of memory into 2 categories.

i.  Declarative memory which is accessible conscious recollection, you can declare it, you can talk about what you remember.

ii.  On the other hand we have procedural memory which are skills and habits that are things that you do that you don’t think through as you are doing them and you can’t easily tell anybody exactly how you are doing them. You’ve all been watching the winter Olympics, I doubt that many of the skaters last night could talk you through exactly how they were making their spins. They’ve learned how to make them, if they had to think through them they wouldn’t be able to make them that fast.

V.  Chart [S5]

a.  Long term memory then we have explicit or declarative memory and implicit or procedural memory over here. Just quickly look at this memory over here first then at this point out the different areas of the brain subserve this memory compared to this explicit memory. Especially when we look at the striatum and the cerebellum and amygdala with emotional memory with explicit memory dealing more with the cortical areas that Dr. Lester already talked about. Look at the implicit memory or procedural memory first. This is a type of memory that you have that all of you have for instance if you’ve been doing it for very long your keyboard skills are procedural, you don’t have to think about where the ‘R’ is. If you play the piano they are procedural. One thing to note here though is that something that one day is explicit can become implicit. How many play the piano, chess, baseball? When you first learn what did you do? You essentially had to think through every move you were making, even in keyboarding, you had to think through where are those letters. Using a visual memory of that, but if you had to keep doing that you never would’ve gotten proficient. All of you are learning to use the drill or to use your optometry set-ups right? You probably have to do a lot of thinking as you are doing it, and there is a lot of fear induction when your instructor is standing over you saying “No you are going to drill through the tooth..” right now you have to think through every point, but if you had to do that in your careers, with optometry or dentistry you wouldn’t be very proficient. You have to have these habits and skills you develop that you don’t think through that become part of the implicit memory.

VI.  Classical Conditioning [S6]

a.  Repeating stimuli together makes an association. Dr. Lester already showed you this.

VII.  Pavlov’s Dog [S7]

a.  Pavlov’s dog. Simple operation, you ring a bell normally the dog doesn’t respond, it could care less about the bell. If you present a McDonald’s Big Mac there the dog starts salivating and if you ring the bell before the hamburger presentation the dog will learn the association and now when the bell rings later he will salivate because he expects there to be a reward of a hamburger. Note that when you have this kind of positive learning, you have to have a close association between the conditioned and unconditioned stimuli; if they are an hour apart the dog is not going to learn it. Also this condition stimuli has to come before the unconditioned, so you present the hamburger first and he starts salivating and then you ring the bell he could care less, he won’t get the association. Same thing with humans. That is kind of task that has been looked at.

VIII. Figure 55.12 [S8]

a.  Another example of that is from R.F. Thomson. This is the ringing of a bell, or having a tone playing just before an air puff hits the cornea of a rabbit. He used the rabbit because he could easily chart out exactly what areas of the brain were involved and in this case it is clearly the cerebellum and the deep nuclead* of the cerebellum that were involved in this kind of task. It had nothing to do with cerebral cortex, so it never reached those conscious levels.

IX.  Declarative (explicit) memory [S9]

a.  Okay now declarative memory that is somewhat more of an interest. It does involve the cerebral cortex and so forth.

b.  Declarative memory is accessible to consciousness and can easily be verbalized, you can talk about it. There are 2 major types.

i.  Semantic which is a memory for information, the binge and so forth that you learn facts for tests.

ii.  In the other case it is episodic memory which is memory of when events took place. So you remember your history, you remember this morning when you got up what you did and you can tell other people about that.

c.  So in both cases you can verbalize these 2 types of memories. They have slightly different circuits and we’ll look at those later on.

X.  Capacity for declarative memory storage [S10]

a.  Capacity for declarative memory storage is enormous, you know a lot of times you don’t think it is, you don’t really have to get rid of all of the information from the last test you took to learn anything new, maybe you even do that between classes, but you really do have enormous capacity if you can focus on that capacity.

b.  This is an example of a bored college student who decided he needed something to do because his courses were stupid, so he decided he wanted to remember numbers. Most of you could remember 9 digit numbers, telephone numbers, social security n umbers, if I read one off you could probably tell them off back to me. This individual could do that, and after a year later, practicing everyday increasing the number he could remember by 1 he was able to repeat 80 digits after they are ready to his, 1 second apart. Not too bad, none of you could probably do that, maybe someone could

XI.  Capacity for storage [S11]

a.  Couple of other examples of the enormity of the capacity. This is Toscanini, who was the conductor of New York philharmonic, and he knew 250 full symphony scores by memory and could repeat almost all of those back. An example of that is one time an bassoon player walked in and said my B-Flat just broke and the concert is 2 minutes away and I’m not going to get it fixed and Toscanini leaned back and said “Oh vie, there is not a B-Flat for the bassoon in tonight’s concert’

b.  Alexander Aitkin was thought to be a little idle brain by his 5th grade teacher. He kind of like math, but she didn’t think he would ever make anything of himself so in the midst of this he decided to learn pi. And learn it several digits long. How many of you know pi? Everybody knows what pi is, you can look at it on your computer, but how many digits do you know it too? 5? 4? 3? Some of you could care less. Well he learned it to 707, ten years later, he learned that he had an error at digit 537 and they had computers by that time and they used the computer and found the error so he had to rememorize everything from 537 at 30 years old to 707 but then he went along to learn up to 1030. Not bad. Today some master now from Japan Yo was able to do 68,000

XII.  Strategies [S12]

a.  Before you can learn the formula and do it you really have to know where you are and so forth, this is quite amazing that they can get up that far.

b.  You can repeat information and all of you have done that and you have all sat there and said now what the heck did he talk about LTD, LTP, memorize it, memorize it, repeating it to yourself, you all do that.

c.  We now know we can do drugs and not war and maybe Viagra helps you, maybe take a Viagra and you can learn a little bit better the information that you are putting into your brain; it is an expensive way to go though.

d.  Images and we will see examples where in order to remember something you have an image of it. We will see an example of an individual of someone who had sensiesis*, he was able to memorize information by all the senses being involved in that memorization. And relationships so you all know the dirty limericks from gross anatomy where you memorize the cranial nerves or whatever. By song it is easy to remember something so we have all these strategies that allow us to increase declarative memory.

XIII. Human declarative memory [S13]

a.  2 process in this memory. First of all you have to encode the memory, you have to hold the memory in storage and then send it out to the permanent storage sites, as Dr. Lester was just talking about. And then you have to be able to recall that so you have to know the address of where you put that information. You have to have that registry available and you have to have the pathway available in order to draw the information back in. After electric convulsive shock you tend to lose memory for some time before the shock. So this is loss of retrograde, behind memory. You lose that for a short time, but then a few days later you regain that memory so what you really lose is the ability to find the correct registry, you don’t really lose the memory, it is still there. There was this famous neurosurgeon who found the same thing was true when he looked at patients and as a neurosurgeon he was involved in taking out areas that were cancerous and so forth from the brain or areas that were infarcted and removing those because it caused epileptic seizures and so forth. In order to do that he had to make sure he wasn’t hitting any very important areas of brain like motor cortex or sensory cortex so he used electrical stimuli to stimuli the various parts of the brain and what he found is that he would hit portions of the brain occasionally and, these are awake patients, during neurosurgery you are almost always awake, and these patients would report a memory that was long past gone, of when they were 3 or 4 years old and he traced those back and looked at other caregivers or others that knew that individuals and it seemed that the recall was accurate. So the memory was stored but they weren’t able to recall it for one reason or another but the electrical stimulation caused the recall to occur.

XIV.  Loss of memory. [S14]

a.  So a lot of memory are stored, recall becomes very important. Loss of memory by amnesia. We know a lot about learning and memory in humans because of patients that we’ve studied that have had amnesia; we will look at a couple of different examples of these patients. The first one is neurosurgery, doing the right thing and really screwing up. We will look at trauma patients and then a stroke patient and then finally we’ve learned a lot from infections, degenerative disease we will talk about briefly and electroconvulsive shock.

XV. Neurosurgery [S15]

a.  1st patient this is HM in 1953. HM was an engineer. HM had a problem though, he was intractable epileptic, he had grand-mall seizures about once a day and he was unable to carry out his normal functions and so he decided he was going to go to the neurosurgeons at McGilla University and they were going to fix him. They said well how would you fix this? They knew from their EEG recordings that at every point, every time the seizure occurred it began in the temporal lobe. They said to themselves, well we know the temporal lobe doesn’t do anything so let’s just excise it, suck it out. And that is what they did.

XVI.  HM studied [S16]

a.  Unfortunately when HM woke up he was profoundly amnesic, he had normal short term memory, about 30 seconds worth, but he couldn’t remember anything past that point of new information. He had excellent recall of old information before the surgery, he could tell you all about it, better than other individuals looked at, control individuals. But he was unable to encode new memories and really profoundly so, just an example of that: Brenda Miller who followed him for 55 years as a neuropsychologist would ask him for instance when he walked in the door, could you hand me your wallet, she would take his wallet and put it on the filing cabinet behind where he sat and he sat down. And would ask where is your wallet, and he would say right there, then would ask again and he would respond with right there. Then she would ask how he felt today and how was the weather, then would ask again where is your wallet and he would feel around for it in his pockets then decide he’d left it at home.