Module 37 - Memory Flashcards
What are the categories of human memory?
- Qualitative categories
- Declarative vs non-declarative/procedural
- Temporal categories
- Immediate vs working vs long-term
What are the different qualitative categories of memory?
Declarative vs non-declarative/procedural
What are the different temporal categories of memory?
Immediate vs working vs long-term
What is the general concept of qualitative categories - “types” - of memory (the hierarchy)?
- Declarative = available to consciousness = you can say it out loud → often can be learned in a single exposure (one trial learning)
- Nondeclarative = generally not available to consciousness → usually requires many repetitions (gradual learning)
What is the general concept of temporal categories - “stages” - of memory (the hierarchy)?
- Immediate memory
- Working memory
- Long-term memory
What is the timeframe of each of the temporal categories - “stages” - of memory?
- Immediate memory
- Fractions of a second-seconds
- Working memory
- Seconds to minutes
- Long-term memory
- Days-years
What are the different anatomical structures that are involved at different times in the storage of explicit memories? (important question)
- Less than 1 second (“attention” or “registration”)
- Brainstem - diencephalic activating systems, frontoparietal association networks, specific unimodal and heteromodal cortices
- Seconds to minutes (“working memory”)
- Frontal association cortex; specific unimodal and heteromodal cortices
- Minutes to years (“consolidation”)
- Medial temporal structures; medial diencephalic structures; specific unimodal and heteromodal cortices
- Years
- Specific unimodal and heteromodal cortices
True or false: you can forget things at any moment of the continuum of stages of memory.
True
Which memory is implicit and which memory is explicit?
Declarative memory is explicit and nondeclarative memory is implicit
What are some of the characteristics of declarative memory?
- Explicit memory
- Easily verbalized
- Conscious
- Often can be learned in a single exposure (one trial learning)
Which structure(s) of the brain is responsible for forming new declarative memories? (important question)
Hippocampus and the diencephalon (which is composed of the thalamus and the hypothalamus)
Which structure(s) of the brain is responsible for storing declarative memories?
Occurs in diffuse cortical areas
What is the case of H.M. (1926-2008)
- He has a bilateral medial temporal lobe resection (1953)
- Removed hippocampus, amygdala, temporal cortex
- He then could not form new memories: problem with consolidation
- No problem with old memories → long term memory
- Some measures of memory were not affected
- WHAT WAS IMPACTED WAS THE TRANSFER FROM THE IMMEDIATE MEMORY TO LONG-TERM MEMORY = HIS WORKING MEMORY WAS IMPACTED
What happens 2 years post-operation in the case of H.M. (1926 - 2008)
- Intelligence scores similar to pre-operation
- No deficits in perception, abstract thinking, or reasoning
- Could form non-declarative memories
- BUT he could not form DECLARATIVE memories
How were we able to determine that H.M was able to form non-declarative memories?
- The number of errors to form the task of drawing between the lines in a mirror = # of errors decreased
What was everyday life like for H.M?
- Obvious inability to recall events n his daily life
- Memory deficiency was “permanent”
- “Every day is alone… whatever enjoyment I’ve had and whatever sorrow I’ve had.” -H.M
What is the difference between retrograde amnesia and anterograde amnesia? (important question)
- Retrograde amnesia (RA) is a loss of memory-access to events that occurred or information that was learned in the past. It is caused by an injury or the onset of a disease.
- Anterograde amnesia is a loss of the ability to create new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact.
There is another case called patient N.A. He was in a fencing foil accident and damaged his thalamus and mammillary bodies in the brain (without damage to other parts in the brain). What type of deficits did the patient have? What are the structures that this patient damaged known for?
- Similar amnesia to H.M. case
- The thalamus and mammillary bodies are particularly sensitive to alcoholism → they degenerate.
- Can present with anterograde and retrograde amnesia
What is Korsakoff’s syndrome?
- Alcoholism, thiamine (B1) deficiency
- Thalamus and mammillary bodies degeneration
- Anterograde and retrograde amnesia
What did these cases teach us? What are the important structures for declarative memory? (important question)
- Midline diencephalic structures
- Left diencephalic lesions: verbal memory deficits
- Right diencephalic lesions: visual-spatial memory deficits
- Medial temporal lobe structures (hippocampus)
- Establishes new declarative memories (inability = anterograde amnesia)
What happens with a left diencephalic lesion? (important question)
Verbal memory deficits
What happens with a right diencephalic lesion? (important question)
Visual-spatial memory deficits
What did the study with the taxi drivers in London demonstrate?
- The number of months spent as a taxi driver (months) correlated with the size of the hippocampus
- The time spent learning the roads of London = meant a larger hippocampus volume
- This tells us that the hippocampus has a very important role in establishing new declarative memories.
What is retrograde amnesia is typically more indicative of what?
Retrograde amnesia (loss of events preceding injury) more indicative of generalized lesions associated with head trauma &/or degenerative disorders
Anterograde amnesia is typically indicative of damage to which structures?
- Midline diencephalic structures
- Medial temporal lobe structures (hippocampus)
Immediately after a TBI injury, what can we expect to see in a patient?
- Immediately after the injury, when the patient cannot form any new memories and suffers from anterograde amnesia, typically associated with:
- Restlessness
- Increased agitation
- Disruption of the sleep/wake cycle
- But they also have preserved memories from long ago
- Typically know who their family is
- Typically know where they work
- Etc.
- But they also have a small retrograde amnesia period.
What is the goal standard measurement for objective tests after a TBI?
- GOAT = The Galveston orientation and amnesia test
- A clinically useful tool for monitoring post-traumatic amnesia
What type of question does the GOAT assessment ask?
- Ask questions about long term memory
- When were you born and what is your name
- Ask questions about immediate memory
- Where are you now and how did you get here
- Ask questions surrounding the accident → the time around the injury to the head
- When were you admitted to the hospital
What is a normal score on the GOAT?
Normal = 76 - 100
What is a borderline score on the GOAT?
Borderline = 66 - 75
What is an impaired score on the GOAT?
Impaired < 66
True or false: The GOAT is used to determine when a patient is ready to move on from the acute care site to the rehab site.
- True, we want to use the GOAT to have a good idea if the patient is able to remember and retain new information.
- Rehab center you will need to start remembering and retaining new info, therefore it would not be appropriate to transfer the patient when they are in a state of post-traumatic amnesia
What type of scoring would a patient have on the GOAT in the post-traumatic amnesia phase after the TBI?
GOAT < 75 but it will diminish over time
What is the interpretation of the GOAT?
The duration of post-traumatic amnesia (PTA) is defined as the period following a coma in which the GOAT score is < 75. PTA is considered to have ended if a score > 75 (sign should be greater than) is achieved on three consecutive administrations (3 different days for example)
Fill in the blanks !!! (important question)
IMAGE
We know how (kind of) new memories are formed, meaning that we know what brain structures are important for forming new memories. BUT, where are the long-term declarative memories stored?
- Storage occurs in the cortex
- Storage site related to the modality in question (e.g. visual cortical areas appear to be involved in storing visual memories)
- Degradation in long-term memory proportional the amount of cortex damaged (mass action principle)
- If a lot of your cortex is damaged, you are probably going to lose a lot of memory.
Where is the acquisition and storage of declarative information for short-term memory storage?
Hippocampus and related structures
Where is the acquisition and storage of declarative information for long-term memory storage?
A variety of cortical sites: Wernicke’s area for the meanings of words, temporal cortex for the memories of objects and faces, etc.
What happens when you aks a patient to recall one of the images you have shown to them on a screen after a series of pictures, for example, a chair?
- The same areas of the brain light up when you are perceiving an object as when you are recalling/ imagining it.
- In this case, imagery is remembering = considered as memory
- You can see that the blue spaces light up = the chair
- This concludes a theory that memories are stored in the cortex or part of the cortex that is responsible for the modality
- For example, if you remember how someone’s voice sounds like = it would be stored in the auditory cortex.
Why are we better at remembering an image of food when we are hungry?
Motivation → better at remembering things about food when we are hungry
What is procedural motor learning?
- Example → HM star diagram
- Skiing
- Shooting a basketball
- Riding a bike
- Dancing
- Playing the guitar
- It is motor learning → therefore all the brain structures that ADAM talked about for motor learning are also important for procedural motor learning.
What is the basal ganglia’s involvement in procedural motor learning?
- We know that the Basal Ganglia is extremely important for motor learning and motor skill acquisition.
- A study has been done → different doors and where a reward was behind one of the doors; patients with Parkinson’s disease that did not have their dopamine medication → did not do very well with this task = to notice that the reward was behind a specific door/ then when on medication patients did better and controls = not with PD = did great.
- This just serves as a bit of support to know that dopamine and the basal ganglia re important for procedural motor learning.
Where is the acquisition and storage of nondeclarative information for short-term memory storage?
Sites unknown but presumably widespread
Where is the acquisition and storage of declarative information for long-term memory storage?
- Cerebellum
- Basal ganglia
- Premotor cortex
- And other sites related to motor behavior
Explain the study to show how priming works.
- Participants are shown “primed” list under false pretenses (for example, within a paragraph)
- Later asked to complete word stem list (task 2) - contains stems of words and both primed and unprimed list.
- In task 2, participants complete stems of primed words to form primed words themselves more often than chance would predict.
- What this means is that because the individual had seen the primed words before, the patient was much quicker to fill in words like “element” or “technical” because these words where primed.
Is there an evolutionary pressure on neural connections for some “memory”? How do we know?
- Yes, some “memory” appears to come from evolutionary pressure on neural connections.
- From birth (i.e. before they could have learned this association), baby birds are scared of shadows that look like predators, but not other shadows… proves that it is learned before they are born.
What are the different memory cellular mechanisms involved at different times in memory storage?
- Seconds to minutes
- The ongoing electrical activity of neurons
- Changes in intracellular Ca2+ and other ions
- Changes in second messenger systems
- Minutes to hours
- Protein phosphorylation and other covalent modifications \
- Expression of immediate early genes
- Hours to years
- Additional changes in gene transcription
- Translation resulting in structural changes of proteins and neurons
What are the different anatomical structures involved at different times in the storage of explicit memories?
- Less than 1 second (“attention” or “registration”)
- Brainstem-diencephalic activating systems
- Frontoparietal association networks
- Specific unimodal and heteromodal cortices
- Seconds to minutes (“working memory”)
- Frontal association cortex
- Specific unimodal and heteromodal cortices
- The ongoing electrical activity of neurons
- Minutes to years (“consolidation”)
- Medial temporal structures
- Medial diencephalic structures
- Specific unimodal and heteromodal cortices
- Years
- Specific unimodal and heteromodal cortices
Can we observe physical changes associated with memory storage/performance?
- There is structural changes that occur with learning and memory
- For example, the hippocampal volume (related to remembering spatial information) correlated with time as taxi driver (a job which depends on skill in this area)
- Hippocampal = responsible for spatial information
