PSY290H5 Lecture Notes - Lecture 9: Basal Ganglia, Limbic System, Don Valley Parkway
PSY290 Lecture 9
A Brief History of Memory
Exam Information
Short answer (6) (1 short answer based on the first half)
Fill in the blank (15)
Multiple choice (45)
Labelling --> questions before the midterm (anatomy section)
Total: 97 marks
2 hours to complete
Emphasis on material since the mid-term (75% of the exam)
TopHat Question: NMDA receptors allow Ca2+ ions to flow through
Sodium does not pass through NMDA whatsoever
Sodium passes through AMPA (non-NMDA)
Calcium contributes to the stimulation of all the enzymatic events inside of the receiving end (the
dendrite) that can then change how a dendrite works, how efficiently it operates, and how much
new protein that is relevant to synaptic activity is produced. Calcium influx stimulates creb to be
turned on, which produces proteins, that get inserted in to the synapse, increases the efficiency of
how a synapse works.
TopHat Question: What neuronal features change as a result of learning?
a. Number of neurons (never)
b. Frequency of action potentials
a. Limited evidence that suggests they can increase in frequency
c. Size of graded potentials
d. Number of axons
e. Number of post-synaptic receptors
TopHat Question: Where are memories stored?
Hippocampus
Today, we will get a more detailed idea on where memory is stored
Lecture Content:
Patient H.M: the most studied individual in psychology
His hippocampi were removed
If we think of a study of memory, the history of our understanding is a little bit spotty and it
started in the late 1800s when Theodore Ribalt described diseases in memory. He was calling
attention to the nature and time course in amnesia and accompanies dementia that followed it. he
pointed out that on one of the key characteristics of patient with amnesia is that they lose the most
recent memories and the old memories seem to be reserved. They can remember old memories in
the greatest detail but forget their son’s name. this gradient of memory loss that occurs in people is
called the Ribot’s Law --> describes the memory gradient with dementia
Early 1900s: a Russian psychiatrist also described a series of patients who happened to be
alcoholics and exhibiting neuropsychiatric syndrome that involved memory loss and
characterizing this memory loss, he described them as repeating themselves, not recognize the
examiner from one day to the next, and yet still were typically and remarkably able to remember
events before the illness or alcoholism. We have this gradient that starts to emerge. Not all
memories start the same and it takes a long time for memories to be fixed
find more resources at oneclass.com
find more resources at oneclass.com
Someone in Germany: Carl Wernicke also described a clinical syndrome involving gait ataxia:
failure to move effectively and it also involved some element of amnesia. He was interested in
what is changing about these individual’s brains, upon autopsy, he took a look at everything
different in these individuals. It seemed that there is a different in the thalamus, hypothalamus,
and the mammillary bodies. Mammillary bodies are in relevance to us. What he noticed is that
the mammillary bodies of these individuals all had significantly lower brain weights. He thought
that the loss of memories had to do with loss of tissue in the brain and especially the mammillary
body.
At the same time. Arnold pick described Pick’s disease which is a loss of memory. What he added
is something about the pathology of individuals. The brain of individual with this disease: the
back of the brain (occipital and parietal) look normal but the front of the brain does not look
normal. The front of the brain has bigger sulci and smaller gyri. The gradient is brain structures.
Pick and Wernicke identified differences in brain structures: mammillary body and the front of
brain
Bekhterev looked at interesting structures tucked inside the temporal lobe called medial temporal
lobe deficit. In his patients with memory loss, he noticed that the medial temporal lobe appeared
softer. Inside of that medial temporal lobe, we now know is where the hippocampus exists.
The 3 structures: mammary body, the front structures of the brain, and the hippocampus
Understanding of the localization of memories improved in the 1950s. William scoville reported
and published on a profound memory loss of two patients that he had recently treated for
uncontrollable seizures and for both patients, the treatment was to damage the medial temporal
aspect of the brain. Of those two patients, one of the patients unfortunately made a very poor
recovery and his condition declined. His other patient was patient HM who seemed to make a
fairly good recovery. Patient HM had a bike accident and back in the 1940s, they didn’t wear
helmets. As a result of that, he developed seizures and they got worse as he aged. By the age of
25, he could no longer hold a job or function as a person. The only solution was to seek medical
treatment and Scoville (a neurosurgeon) suggested that his stroke focal point was the medial
temporal lobe. In 1950s, he got a hand drill and physically drilling a hole in the frontal lobe. After
the surgery, patient HM got a really profound memory less. This interested Donald Hebb and
Brenda Miller. She was one of the most renowned researchers on memory and spent 50+ years
working with HM until his death in 2010. HM did not have a complete loss of memory, he was
able to do a few things. He could remember skills like mazes and puzzles.
Brain Regions Crucial for Forming New Memories
Not all memories are formed inside of the hippocampus
HM has less gray matter in the area of the medial temporal lobe
HM was able to remember things like where he grew up as a kid, he knew his parents, his friends.
He had memories but he suffered from anterograde amnesia.
He couldn’t remember things that would happen on from a certain point
Memories that were already in place weren’t affected
Memories like where your first birthday was being NOT in the hippocampus
Memory is NOT one thing, there are distinct types of memories
There are multiple memory systems
Question: what did HM help us learn?
HM had a decent ability to remember a phone number so long as he rehearsed it in his head
He can digit span and block-tap
HM did well in physical motor tasks
find more resources at oneclass.com
find more resources at oneclass.com
oMirror-image tracing task
oHe had to trace out in a pencil inside the lines
oBrenda would count the times the pencil would hit outside of the star
HM improved on the task even within one day and this indicates that practice is working for him.
If performance is improving, it is evidence of motor memory
This carried with him from one day to the next.
By the time we get to day 3, we barely get any errors and this is indicative that he IS able to form
new memories
Hippocampus is NOT the only place relevant for old memories OR memory formation either
Reading backwards does not require an intact hippocampus
Although HM was not able to physically recall new memories
HM starts to get the incomplete memory formation right with practice
HM makes a ton of errors on the first time and none at the end
Allow an hour to pass with distraction, you ask him have you seen this experiment, he’ll say no
but he actualy does better on the task. Subconsciously, he is able to respond that indicates that he
has the formation of a long-term memory. It’s just that is is not consciously AWARE of it
Major contributions of HM’s Case
medial temporal lobes are involved in memory
STM, remote memory, and LTM (in the past that we can hold on to) are different and separate
oThe airplane task suggests that HM CAN form LTM
Memories can actually exist but not consciously recalled
oDo you remember? NO
oDo this task. Yes, I can do it
Two main types of memory
a. Declarative
a. “I know it”
b. Procedural
a. “I can show it”
Part Two:
HM made contribution to the 2 different types of memory
Early reports that tried to damage the hippocampus in animals did not end up with anything
oMice could do all the functions and tasks
oThey realized that the type of task that we’re asking to form is NOT asking the animal to
declare the memory
oHow do you get an animal to declare that they remember something?
oIn 1960s, a particular task was developed that accessed animal’s declarative memory
oWhat happens is you typically ask an animal to say to declare that they remember
something being present
oLet’s say you have an option between a key and a ball and the key has been previously
presented
oThe animal is rewarded every time they get a key
oBut picking up a key could be a sign that they’re remembering that there’s food OR that it
simply is familiar to them --> not necessarily indicative
oTask: presented with an object like a key on the first trial, and were rewarded
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Short answer (6) (1 short answer based on the first half) Labelling --> questions before the midterm (anatomy section) Emphasis on material since the mid-term (75% of the exam) Tophat question: nmda receptors allow ca2+ ions to flow through. Sodium does not pass through nmda whatsoever. Calcium influx stimulates creb to be turned on, which produces proteins, that get inserted in to the synapse, increases the efficiency of how a synapse works. Today, we will get a more detailed idea on where memory is stored. Patient h. m: the most studied individual in psychology. If we think of a study of memory, the history of our understanding is a little bit spotty and it started in the late 1800s when theodore ribalt described diseases in memory. They can remember old memories in the greatest detail but forget their son"s name. this gradient of memory loss that occurs in people is called the ribot"s law --> describes the memory gradient with dementia.
