Chapter 11 Flashcards
Learning, memory, and amnesia (105 cards)
1
Q
Sensory memory (amount of time and number of item it can hold, consciousness of the process, what does it hold)
A
A Few seconds after the stimulus left our environment, almost illimited capacity, unconscious process, holding sensory information/impression
2
Q
Short-term/working memory (amount of time and number of item it can hold, consciousness of the process, what does it hold, and the difference between the two types)
A
15 secondes, 5-9 items at a time, conscious process holding information you are paying attention to, working memory is what we call a short term memory that we can manipulate/reorganize
3
Q
Long-term memory (what does it hold, amount of time and number of item it can hold)
A
Holding informations that has been consolidated, has an illimited storage, and the amount of time it can hold a memory depends on how well the consolidation process was made, but could be forever.
4
Q
When memories are in the long-term memory they are in an ____ state, when they are in the short-term memory they are in a _____ state.
A
Inactive and active
5
Q
What is the consolidation process? (What and how, and how long it takes)
A
Making new memories stables by strengthening them often with repetition, or how important the information is. Many things will play a role in consolidation. It can take up to many years, about 3 years for the memories to be fully consolidated without being disturbed.
6
Q
What is the process of retrieval?
A
When we think of a memory - Bringing a memory from an inactive state in our long-term back to an active stsate in our short-term
7
Q
Subsystems of the longterm memory + conscious or unconscious?
A
Explicit/Declarative memory conscious, containing semantic and episodic memory
Implicit/Non-declarative memory unconscious, containing procedural memory, classical conditioning, and priming
8
Q
Semantic vs episodic
A
Facts and language vs own personal experiences
9
Q
Procedural memory?
A
Memory for skills and actions that cannot efficiently be explained verbally, moment/process of learning cannot be recalled
10
Q
Classical conditioning
A
Unconscious learning process associating a neutral stimulus (no particular response) with a significant stimulus (response inducing)
11
Q
Unconditioned Stimulus (UCS)
A
Stimulus that naturally triggers a response without prior learning
12
Q
Conditioned Stimulus (CS)
A
Stimulus that initially doesn’t trigger any response but can with classical conditioning
13
Q
Unconditioned Response (UCR)
A
Natural response to an unconditioned stimulus
14
Q
Conditioned Response (CR)
A
Learned response to the conditioned stimulus
15
Q
The Little Albert experiment (Process, Problems)
A
- Infant Albert is presented to a rat (neutral stimulus)
- Albert is presented to a loud sound (significant stimulus/UCS) that scares him - UCR
- Every time Albert was reaching for the rat, the loud sound was played - Paring of the two stimulus
- Albert is now scared of rats (now CS) - CR
16
Q
What is the problem with the little Albert experiment?
A
It is underestimating the importance of classical conditioning in our lives and how it is constantly guiding our actions.
17
Q
What is priming?
A
The unconscious influence of previous knowledge and experiences on how we respond to other things.
18
Q
Types of amnesia and what they are
A
Retrograde - Impairment in memories that happened prior to the event impairing memory
Anterograde - Impairment in new memories after the event impairing memory
19
Q
Why after a head injury is it important to know the length of the retrograde amnesia?
A
Gives a good indication on the severity of the injury
20
Q
Hebb’s theory (What and what does it explain)
A
Memories are stored in the short-term memory (seconds or minutes) in a reverberating loop of neural activity, keeping the memory alive. This constant recall leads to physiological changes at synapse level, leading to long term storage, that will be strengthen over time (over years) to stabilize the memory.
21
Q
What does Hebb’s theory explains?
A
Explaining why interference of this process can result in retrograde memory loss
22
Q
What is the name of the study done on animal to prove Heeb’s theory?
A
Animal study of electroconvulsive shock (ECS)
23
Q
Animal study of electroconvulsive shock (ECS) process
A
Familiarization: rats in a box with an empty niche for 10min a day 5 days.
Learning trial: Water is placed in the niche and rats learn where it is located
ECS treatment: different groups had different time intervals (10 seconds, 1 minute, 10 minutes, 1 hour, or 3 hours) to interfere with memory consolidation and two control groups: one did not receive shocks, one did not have the learning trial.
Recall test: rats are placed back in the box to see if they remember the water
24
Q
What were the results of the Animal study of electroconvulsive shock (ECS)
A
Rats who received ECS soon after learning (10 seconds to 10 minutes) showed retrograde amnesia and forgot where the water was, they went to the water as often as the control group who did not have the learning trial.
ECS applied later (1 hours) had less impact on memory.
ECS applied 3 hours later had no memory loss and when as much as the group that was not shocked, they went directly to the water.
25
What are the problems of the Animal study of electroconvulsive shock (ECS)
Testing memory with thirsty rats in a box could not be directly applied to humans. Also, the human brain is much more complex and the consolidation process takes much longer.
26
Human study with electroconvulsive shock (ECS) process
1. Before the treatment, patients were tested on their memory of TV showed that aired only one season from different years (1-3, 4-5, 6-7, 8-9, 10-17 years prior)
2. After the treatment, patient were tested again on these shows
27
Results and conclusion of the human study with electroconvulsive shock (ECS)
For very old shows (10-17 years), patients performed equally well before and after ECS - memories were well consolidated.
For recent shows (1-3 years), patients performed much better before receiving ECS, - memories of recent shows were still in the process of consolidation and stabilization.
For shows between 4-9 years old, patient performed similarly before and after ECS
Conclusion: The study showed that memories take at least 3 years to become consolidated enough to resist neurological damage from ECS. This suggests that human memory consolidation is a fragile process that lasts longer than in rats.
28
What is the name of the theory stating that memories can be altered?
Reconsolidation theory
29
Explain more in detail the reconsolidation theory.
When the memory is retrieved back from it's inactive state into the shot-term memory, it can be modified or altered before being reconsolidated.
30
Application of the reconsolidation theory in patient with PTSD.
Patients are learning to stay in a relaxation state when retrieving the memories, altering the physiological body response when the memory comes back up, because the brain will have reconsolidated this memory as less traumatic.
Medication can also be used to help the relaxation process, but less effective because the patient was less involved in the process and his own mental reaction did not change.
31
why is the patient H.M. case so important?
It helped us understand the different memory systems (explicit vs implicit, consolidation vs retrieval) and the importance of specific structures in the brain for memory (like medial temporal lobes)
32
What resection did H.M. had, where is it, and was is it containing?
Resection of the medial temporal lobes bilaterally, containing the hippocampus, the amygdala, and the rhinal cortex - Inner regions to the temporal lobe containing the hippocampus, the amygdala, and the cortex around it.
33
Where did we think memories were stored before H.M.'s case and what did we think or the hemispheres roles?
We thought that memory was all over the brain and that the right hemisphere was a spare hemisphere for the brain.
34
What were the after effects of H.M.'s retrograde memory?
Mild amnesia from 2 years prior to the surgery.
35
What were the after effects of H.M.'s anterograde memory?
Severe impairment. Unable to form most type of new memories
Explicit: Was gravely impaired because the process of consolidation was impaired.
1. He could not form new episodic memories.
2. He could learn to a certain extend new facts and words (semantic memory).
3. He had difficulty with mental time travel - describing/imagining past and futur events, giving vague and generic descriptions.
36
Why did H.M. had impairment in mental time travel?
The neural networks involved in memory consolidation that was gravely impaired are overlapping with the neural network we use to imagine future events.
37
Who was the main neurologist working on this case?
Branda Milner
38
Why is Branda Milner important?
1. She was able to show that the different subtypes of memories (implicit and explicit) had different neural networks, showing that even with one impaired, the other one can work just fine.
2. She demonstrated that the entirety of the frontal lobe is essential to learn from feedback and to integrate it, adjusting your behaviour accordingly.
3. She was the first to show that the right hemisphere was not the spare tire, but was important for many cognitive functions.
4. She had the intelligence to take existing tests and modify them to dissociate different memory subtypes.
5. She is the inventor of neuroscience!
39
What was shown in the assessment of H.M.'s explicit memory?
1. His short-term was within normal limits
2. His consolidation process was greatly impaired in the verbal and visuo-spatial domaine
40
What were the different tests done to assess H.M.'s memory?
Digit span test, digit span test +1, block-tapping memory-span test, and block-tapping memory span test +1
41
What is the digit span test, process, scoring, and H.M's result?
Assessing the short-term memory's capacity by making the patient repeat a digit sequence, and increasing the length by one digit till a mistake is made.
The length of the longest sequence correctly repeated is the capacity of the verbal short-term memory.
H.M. was able to do this test within normal limits
42
What is the digit span test +1, process, scoring, and H.M.'s results?
Assessing the process of verbal memory consolidation and how well information can be transferred for short-term to long-term memory.
After assessing the verbal short term capacity with the standard test, a new sequence is presented exceeding by 1 the short-term capacity.
If unsuccessful, the same sequence is repeated to provide an opportunity for consolidation.
Successful completion of the test demonstrates consolidation into the long-term memory
H.M. was never able to accomplish this test.
43
What is the digit block-tapping memory-span test, process, scoring, and H.M.'s results?
Assessing visuo-spatial short-term memory
Many blocks are placed in front of the patient and he will repeat the tapping sequence after the examiner. The sequence will increase by one block until a mistake is made.
The length of the longest sequence correctly done is the visuo-spacial short-term memory capacity
H.M. was able to do this test within normal limits.
44
What is the digit block-tapping memory-span test +1, process, scoring, and H.M.'s results?
Assessing the process of visuo-spacial short-term memory consolidation, how well information transfer from short-term to long-term memory.
After assessing the visuo-spacial short term capacity with the standard test, a new sequence is presented exceeding by 1 the short-term capacity.
If unsuccessful, the same sequence is repeated to provide an opportunity for consolidation.
Successful completion of the test demonstrates consolidation into the long-term memory
H.M. was never able to accomplish this test.
45
What tests were done to assess H.M.'s implicit memory?
The mirror-drawing test
The incomplete picture test
46
What is the mirror-drawing test, process, scoring, and H.M.'s results?
The participant is asked to trace within boundaries in a star shape while looking at its reflection in a mirror. They cannot see their hand or the actual paper, only the mirror image. The task is repeated over multiple trials and sessions.
Mistakes like drawing out of the lines are recorded, and the improvement of the performance if observed over time.
H.M. showed significant improvement over time, but had no memories of previously doing the task.
47
What is the incomplete-picture test, process, scoring, and H.M.'s results?
The participant is asked to identify the objects in a series of incomplete drawings, starting with the least detailed version. If they cannot identify the object, they are shown a progressively more complete image until they can. The task is repeated over multiple session
The amount of details needed to identify the object and the improvement over time are observed
H.M. showed significant improvement over repeated trials, even though he had no memory of previously doing the task.
48
What are H.M.'s result for the mirror-drawing test and the incomplete-picture test demonstrating?
His procedural memory was intact.
49
What are the most important contribution of the H.M. case (3)?
Memory distribution in the brain - memory is not equally distributed, and the medial temporal lobes are involved in memory consolidation
Distinction between implicit and explicit memory - Showing that some memories exist but cannot be recalled.
Distinction between episodic and semantic memory - were starting to be made
50
Why is the episodic and semantic memory hard to assess?
People use semantic memory to compensate and fill in gaps in the episodic memory, completing the blanks with general knowledge.
51
What happened to patient R.B. during surgery?
The pump circulating his blood flow stopped for a couple of minutes, creating a global cerebral ischemia.
52
What is a global cerebral ischemia?
Interruption of blood flow in the entire brain, normally happening during a heart attack.
53
What was the damaged caused on R.B.
He had severe anterograde amnesia, due to bilateral damage to area CA1 of the hippocampus.
54
Why is the R.B. case so important?
We did not expect damage as important as this. It is a very contrasting case with the H.M. case. He had only a small leisure of the hippocampus, but still profound anterograde amnesia.
55
What did we learn with the R.B. case?
Damage of the hippocampus can cause profound anterograde amnesia even with very small lesions, and not only with bilateral resection of the whole medial temporal lobe.
56
What movement did the R.B. case start in neuroscientists?
Many research programs were started to find what are the specific contributions to memory functions.
57
Name the other causes of amnesia we learned in class.
Korsakoff's syndrome
Amnesia after concussion
Alzheimer's disease
58
What is Korsakoff's Syndrome?
A permanent neurological disorder characterized by profound anterograde amnesia.
59
What is Korsakoff's syndrome caused by and why?
A chronic deficiency in vitamin B1/Thiamine, essential for brain functioning and has to be ingested.
60
What are Korsakoff's syndrome cognitive and physical problems?
Confabulations
Hallucinations
Personality changes
Physical balance problems
Severe anterograde amnesia in early stage
General amnesia later in the disease
61
What are confabulations?
Distortion in memory, mixing up time-line of life.
62
Brain damage in Korsakoff's syndrome.
Damage to the medial diencephalon, composed of the thalamus and hypothalamus.
63
The discovery of Korsakoff's syndrome lead to?
Research on the role of the diencephalon in memory functions - Research showed that it is important for the temporal information of memories
64
Treatment for Korsakoff's syndrome?
No treatment or reversal of the damage possible. Administration of a high dose of vitamin B1 can help with the progression and slow it down.
65
Name of amnesia after concussion
Post traumatic amnesia
66
Type of amnesia after concussion
Anterograde and/or retrograde
67
Post concussion, people are most likely to forget what happened ____ _____ the accident. Memories are most likely to be lost if they were not fully ________.
Right before and consolidated
68
_______ _______ states that the loss of memory is not uniform over time. More recent memories are typically _____ impaired than older memories, because the accident ________ with the _______ process.
Temporal gradient, more, interfered, consolidation
69
Temporal gradient is agreeing with which theory?
Heeb's theory
70
What is the name of the test did with monkeys to explore the hippocampus' role?
The delayed non-matching-to-sample test for monkeys
71
What is the delayed non-matching-to-sample test for monkeys, goal, process, results?
Determining the type of brain damage that causes amnesia, specifically damage to the medial temporal lobe.
Monkey is placed with one sample object with food under it. He can manipulate and discover the object.
Delay period were everything is taken away for some time
The familiar object and a new one are presented to the monkey, The food is under the new one.
This process is repeated, and the food is always under the new one.
A healthy monkey would make the association that the food is always under the new object. Monkeys that had bilateral removal of the medial temporal lobe were not able to do the task.
72
What were the conclusion of the Delayed non-matching-to-sample test for monkeys ?
The role of the hippocampus was still not clear. In monkeys and humans the hippocampus is deep in the brain and surrounded by cortex, when the aspiration method was used to remove the hippocampus, the cortex was removed too, not letting us understand the role of the hippocampus alone
73
What is the name of the adaptation for rats for the Delayed Nonmatching-to-Sample Test?
Mumby Box: Delayed Nonmatching-to-Sample Test
74
Why did they do the Delayed Nonmatching-to-Sample Test with rats?
The hippocampus is not deep in the brain, so it can be easily exposed and tested.
75
What is a Mumby Box?
A rectangle shaped box with two trap doors at each end opening to a new area with food blows.
76
What is the Mumby Box: Delayed Nonmatching-to-Sample Test, process?
A rat is placed in the middle of the Mumby box with the two doors closed. The first door is opened, showing an empty bowl and an object covering the second bowl with food. The rat pushes the object to eat the food.
The object is taken away for the delay period.
The second door is opened with the old object and a new one both covering bowls, but only with food only under the new one.
77
What is the Mumby Box: Delayed Nonmatching-to-Sample Test, results?
Bilateral removal of the rhinal cortex, leaving the hippocampus intact, resulted in impaired object recognition.
Bilateral removal of the hippocampus had no or moderate effects on object recognition
Bilateral removal of the amygdala has no effect on object recognition
78
What is the rhinal cortex?
Area around the hippocampus containing the perirhinal and entorhinal cortex
79
Paradox caused by the fingdings of the Mumby Box experiment?
Complete removal of the hippocampus resulted in no or moderate effects, but in patient R.B. a severe deficit was observed following his global cerebral ischemia lesioning a small part of the hippocampus bilaterally.
80
What were the hypothesis for the paradox of unexpected findings?
Cell hyperactivity effects following ischemia. Hyperactivity of the cells in the CA1 created a domino effect on the surrounding areas outside the hippocampus because of the excessive glutamate release.
81
The damage caused by cells hyperactivity in the CA1 area was not detected, why?
the damage takes time to spread and damage outside of the hippocampus does not show up easily when examining brain tissue - the function of the neurons are affected without obvious structural changes.
82
What study tested the hypothesis on the paradox?
Mumby et al.
83
What is the study of Mumby et al. ?
They tested their hypothesis of cell hyperactivity with Ischemia induced hippocampal lesions in rats.
84
How did Mumby et al. tested the hypothesis?
Group 1: Ischemic rats had a bilateral removal of the hippocampus 1 hours later
Results? They could still perform the Mumby Box Test
Groupe 2: Ischemic rats had a bilateral removal of the hippocampus 1 week later
Results? The rats showed impairments during the Mumby box test and were not able to complete it.
Group 3: Ischemic rats had no removal of the hippocampus
Results? The rats showed impairments during the Mumby box test and were not able to complete it.
85
What can explain the results of the Mumby et al. study?
Group 1: Surgery was done right after the stroke and the damaged area was removed, preventing it from spreading, and leaving the rhinal cortex around it intact.
Group 2: The time allowed the damage to spread beyond the hippocampus
86
The example seen in class of hippocampus neuroplasticity showed the importance of the hippocampus for?
Spatial location
87
What example seen in class showed hippocampus neuroplasticity?
London, UK taxi drivers: They have much more developed hippocampus than other people, their hippocampus grew because of their driving career in the complex city of London.
88
What study assessed the spatial memory role of the hippocampus?
The Morris water maze
89
What is the Morris water maze, process and results?
A rat is placed in a circular water pool filled with water containing a hidden platform.
Pre learning, the rat will swim around until randomly finding the platform.
During the learning phase, the rat is placed at different start location and he have to find the platform.
After learning, the rat will normally swim directly to the platform.
The rats who had their hippocampus removed will never learn and always act like the pre learning phase.
90
What is the name of the cells important for spacial location?
Place cells
91
What are place cells and how do they work?
Specialized neurons in the hippocampal formation that become active when we are in a specific location in our environment. When we become familiar with our environment, different place cells will develop different place fields, together allowing us to create a spatial map of our environment. Place field will correspond to this particular location in our environment, and will activate certain place cells. They will fire when we enter that location.
92
Where are memory stored?
They are distributed across multiple areas that were active during the formation of the memory.
93
Apart from consolidation, what makes a memory more resistant to brain damage?
The more the memory is diffuse in the brain, the more resistant it is to neurological damage.
94
What is the role of the hippocampus in memory?
Spacial location
95
What is the role of the Rhinal cortex in memory?
Object recognition
96
What is the name of the nucleus keeping our memories organized and what is more precisely its role?
Mediodorsal nucleus of the thalamus is keeping our memories in the context of a certain timeline
97
Explain what Hebb's rule of learning is?
Learning must involve synaptic plasticity - Learning happens at the level of the brain cells, suggesting that when co-occurrence occurs, two stimulus (e.g., one CS and one UCS) happening at the same time, the brain links the two stimulus to the same response by strengthening the synapse, making the CS trigger the same response the UCS would trigger. E.g., Stimulus-response learning
98
Give an example of stimulus-response learning? (a precise example was given in class)
1. Puff of air in the face (UCS) = Blinking (UCR)
2. Tone + Puff = Blinking
3. Tone (CS) = Blinking (CR)
E.g., Stimulus-response at brain cell level
1. Puff activates strong neuron connection to the motor neuron making us blink
2. Tone makes a weak connection to the motor neuron, inducing no response
3. Tone + puff will strengthens the synapse between tone and motor neuron
4. Over time, tone as a strong enough synapse to activate the blinking response
99
What is co-occurence
The co-activation of a presynaptic neuron and a postsynaptic neuron. It will strengthen the synapse, even if the postsynaptic neuron was not firing because of that neural signal. Co-occurrence is essential to learning.
100
Give an example of co-occurence.
Neuron A (Puff, presynaptic), Neuron B (Tone, presynaptic), Neuron C (Blinking, postsynaptic)
1. Stimulus activating Neuron A and B are done at the same time.
2. Neuron A activates neuron C, but neuron B is a co-occurrence with neuron C, strengthening their link.
3. Neuron B can now activate neuron C.
101
What is synaptic plasticity?
Changes in the structure of the synapse, changing the effect of a presynaptic neuron on the postsynaptic neuron.
102
Why is synaptic plasticity working?
The connections between brain cells (synapse) can strengthen over time and will change when learning or forming new associations.
103
Who demonstrated synaptic plasticity and what were the process?
Lømo
Electrodes set up to send intense electrical stimulation of neuron from the entorhinal cortex (Presynaptic neuron) to the dentate gyrus (postsynaptic neuron and entrance of hippocampus)
The electrical stimulation caused an increase in EPSP in the postsynaptic neuron, and these effects were long lasting, so the synapse became stronger.
104
How do we call the change in synaptic strength and what is the process?
Long-term potentiation
1. Apply weak stimulus (Establishing a baseline)
Weak electrical signal is applied to the presynaptic neuron, activating the presynaptic neuron, but not the postsynaptic neuron. The connection between the two is weak.
2. Apply strong stimulus (Establishing a baseline)
Strong electrical signal is applied to the same presynaptic neuron, strong enough that the postsynaptic neuron will respond, establishing a connection between the two.
3. Apply rapid shocks (repeated exposure)
Repeated electrical signals are applied to the presynaptic neuron, consolidating the synaptic changes and strengthening the synapse causing synaptic plasticity.
4. Apply weak stimulus again (Show the results)
Weak stimulus signal is applied to the presynaptic neuron, but this time the postsynaptic neuron will respond due to the synaptic plasticity/learning that has occurred.
105
Long-term potentiation is due to?
Repeated stimulation of the synapse.
