Long Term Memory Flashcards
Define Amnesic Syndrome
Profound long-term memory impairment with a relative preservation of all other intellectual capacities
Retrograde vs. Anterograde Amnesia
Retrograde = inability to remeber memories that were encoded prior to brain damage
Anterograde = inability to learn new information after brain damage
What are the two Amnesic related brain damages?
Medial Temporal Lobe Amnesia
Alcoholic Korsakoff’s Syndrome
Describe Medial Temporal Lobe Amnesia
Classic Amnesia syndrome
- They are consious of their memory impairment and will say “i don’t know”
What causes Medial Temporal Lobe Amnesia?
Name exmaples of individuals that had this amnesia
Damage to the hippocampus that results in a grave loss of recent memory
Lobotomy: performed to relieve phsycotic symptoms
- Mesial temporal lobe resection procedure
- Bilateral Hippocampal lesions
What causes Alcoholic Korsakoff’s Syndrome?
How can the syndrome be treated?
Thiamine deficiency + alcohol abuse
- leads to bleeding in the MTL
Can be treated with thiamine, whcih would allow the patient to live and enter the Korsakoff phase
Damage of what areas of the brain are associated with Alcoholic Korsakoff’s Syndrome?
Mammillary bodies
or
Anterior thalamic nuclei
Describe the phases of Alcoholic Korsakoff’s Syndrome
1) Wernicke phase
2) Korsakoff phase
Describe the Wernicke phase of Alcoholic Korsakoff’s Syndrome
transient confusional state
- Gait disturbancce
- Optic apraxia
- Confusion
Korsakoff phase
- Chronic and severe amnesia
- Personality changes
- Tendency to confabulate (fill in memory gaps with false memories)
Example
- Patients can forget as quickly as somone disappearing behind a door and entering and the patient does not know who they are
Where was the site of patient B.J’s damage? (patient who was involved in a bar brawl in England)
Mammillary bodies
Where was the site of patient B.J’s damage? (patient who injured by a fencing accident)
Anterior thalamic nuclei
Where was the site of patient H.M’s damage? (patient who underwent a surgery due to epilepsey )
Bilateral Hippocampal lesions
What are the two distinctions of long term memory?
- Declarative memory
- Nondeclarative memory
Define delaritive memory
What are the two types of declarative memory?
Memory that you can declare into consciousness & consiously recollect
Facts (semantic memory): Who is the president of the united states? or What is the month of the year?
Events (episodic memory): What did you have for dinner last night? or What did you do on your first day at Brown?
Define nondeclarative memory
Give 3 examples of nondeclartive memory
Implicity acessed, shown by preforming a task.
- Skill learning (mirror tracing, mirror reversed reading, tower of hanoi)
- Perceptual priming (prime -> word puzzle)
- Conditioned responses between two stimuli (eye blink + air puff)
What does the distinction between declarative vs. non declarative memory indicate in terms of brain anatomy?
That the medial temporal lobe system is critical for declarative memory
- The hippocampus creates a unitifed representation of memory
What does declarative memory require/reflect?
Requires binding information across cortical areas into unitary representations that can be declared into consciousness
- Episodic memory
- Semantic memory
What does non declarative memory reflect?
Reflects changes within the sensory, motor, and perceptual processing systems themselves
What structures are within the medial temporal lobe system?
- Hippocampus
- Entorhinal cortex
- Parahippocampal cortex
- Perirhinal coretx
Describe the pathway of those systems
1) Perirhinal cortex
2) Parahippo-campus cortex (can feed directly back into entorhinal cortex or into entorhinal)
3) Entorhinal cortex
4) Hippocampus
Define Epesodic Memory, contrast it to semantic memory
Episodic memory = events
- Specific personal experiences from a particulat time and place
- Ex. Memory of your first time riding a bike
Semantic memory = facts
- World knowledge, object knowledge, language knowledge, conceptual priming
- Ex. Memory that a bike is a mode of transportation
What tests were used to determine what type of non-declarative memory is impaired specifically?
What were the results?
What was a pitfall?
Episodic test: Logical Memory subset of WMS
- Read a paragraph
- Had to recall information in paragraph
- Anterograde
Semantic memory”
- Vocabulary subtest of WAIS
- Asking what words mean. (Ex. What does boast mean?)
- Retrograde
Results
- Amnesics were impaired in epesodic test BUT normal in semantic task
Pitfall
- Did not distinguish between retrograde and anterograde
What was the first test used to distinguish between anterograde and retrograde while trying to learn what parts of declarative memory is specifically impaired in amnesic partients?
What were the results?
Studied patient HM’s knowledge of words that were new since his operation in 1953 in comparison to those that were not
- Lexical decision, recall, and recognition of definitions
Results: Temporal Gradient
- H.M. normal on premorbid semantic knowledge, moderatley impaired on knowledge from the 50s, and severley impaires on knowledge from 60s onward
What was the second test used to distinguish between wether amnesic individuals are impaired in their episodic or declarative memory
Assessed individuals who have been amnesic since birth
1) Copying complex visuals and then draw it form delayed recall = They could not draw from memory
2) Recalling information about a story = They could remeber a decent amount immediatley after. Dellayed recall = could not remeber
3) Word list recalling: Memory of words immediatley after is decent. Memory of words after delay is significantly imapired.
What was peculiar about the memory of the patients who have been amnesic since birth
Their semantic memory acquisition was intact, and they progressed through school normally
They performed well on
- Vocabular subtest
- Comprehension subtest
What did Vargha- Khadem et al. propose?
Proposed a heirarchial account of episodic and semantic memory
What does the hierarchial account of episodic semantic memory propose?
Semantic memory is associated with
- Perirhinal cortex
- Parahippocampus cortex
- Entorhinal cortex
Episodic memory
- Hippocampus
How was the hierarchial account of episodic and semantic memory tested?
2 patients who had different hippocampal damage
- They were tested on their recognition of meanings for words introduced after the onset of amnesia
- Results show that they were equally impaired in episodic memory, however patient PS who had damgage to specifically the hippocampus only was more better at the semantic recognition task than patient SS who had damage to the hippocampus and neighboring areas
What does the asymetry of the hierarchial account of episodic and semantic memory potentially argue?
Selective deficit in episodic memory, with an intact semantic memory
However if you have a deficit in semantic memory, you must ALSO have an impairment in episodic memory
What is semantic dementia?
A variant of prontotemporal dementia
What are the 3 primary behavioural variants of semantic dementia?
- Progressive non-fluent aphasia
- Behavioral variant
- Progressive fluent aphasia
What are semantic dementia patients impaired in?
What are they not impaired in?
Impaired
- Semantic Memory
Intact
- Episodic Memory (on non-verbal perceptual tasks)
Name a method through which semantic dementia patient’s semantic memory was tested
What were the results of this testing?
1) Semantic Memory Test: “Name the item (ex. a telephone)”
2) Episodic Memory Test: Perceptually Identical – “Which of the items, did you see earlier (ex. that same telephone, alarm clock, printer)”. Perceptually Different – “Which of the items, did you see earlier (ex. different looking telephone, alarm clock, printer)”.
Results
- Varied in their accuracy of semantic memory, BUT intact episodic memory
- They were perfectly fine under the perceptually identical condition, but impaired under the perceptually different condition
What does the observations on semantic dementia patients, indicate about the hierarchial account of episodic and semantic memory?
Episodic and semantic memory are two functionally independent memory representations
What does the independent account of episodic and semantic memory indicate?
Information can be independently encoded into semantic memory and not episodic memory and vise versa
What does the standard Model of Consolidation assert?
Retrograde memory loss suggests that old memories may not be fully consolidates at the time of injury
Define consolidation
Process by which moment-to-moment changes in brain activity are translated into permanent structural changes
For a period of time those memories that have been aquired are still dependent on the hippocampus until they are made permanent
- Once they are made permanent, they are no longer dependent upon the hippocampus and the medial temporal lobe system
What does the standard model of consolidation asset about permancence and where memories are stored?
- Medial temporal lobe contribution to memory is temporary
- AKA binding by the hippocampus is temporary – the hippocampus is necessary early on to binding a memory into a unified representation
How does consolidation occur and what does it lead to?
Consolidation occurs though repeated activation of representations in coretx that maintain memory independently
1) Overtime with repeated activation
2) A cortical representation that is bound by the hippocampus
3) Gets consolidated and stabilized in the cortex as a representation
4) The hippocampus and medial temporal lobe are no longer needed to bind it together
5) MEMORY is NO LONGER DEPENDENT ON THE HIPPOCAMPUS
What does the standard model of consolidation overall imply?
Implies a time-limited temproal gradient for remote memory
What experiment was performed on Alcoholic Korsakoff Patients that aligned with the standard model of consolidation?
What were the results of the expeirment?
Famous Face Recognition Test and Public Events Questionnaire
Results
- Clear time limited-temporal gradient.
- More recent memories are impaired, older memories are in tact.
What experiment was conducted to mitigate the idea that alchoholics were imapired on their recent memories due to their alcoholism issues?
Patient PV was a famous phsycologist who wrote an academic biography two years proceding his alcoholic Korsakoff diagnosis.
Experimenters used his biography to ask him questions and asess whether he had a temproal gradient
Results:
- He was impaired in remembering more recent memories in his life in comparision to his older memories
Define Transiet Global Amnesia
Rapid onset of antergrade and retrograde amnesia typically lasting 6 to 10 hours
- Typically occurs after a stressfull experience that results in a decrease bloodflow that specifically affects the hippocampus
- Short period of time, hippocampus was disfunctional
- Damage specifically localized to the CA-1 field of the hippocampus
What did testing transient global amnesia patients indicate about the function of the hippocampus?
1) Impaired on all Episodic Memory tasks (except perceptual tasks!! ex: copying)
2) Remote Memory showed a temproal gradient
Why do some amnesic patients NOT show a temporal gradient?
Used differnet methods for matching memories across time periods
- Matching for memorability at time of testing in normal controls
- Memories that keep being rehersed are no longer eposodic memories, but semantisized memories of that experience
Given the relationship between memorability and semantic information, how can the temporal gradient of memory be interpreted?
- The older memories that the Korsakoff patients recall, are not true episodic memories they are more semantic (there is less of a re-living quality)
- The more recent memories that the Korsakoff patients recall, are truly episodic which is a testament to their deficit.
- There are different types of memories across those two time periods
In conclusion
Matching for memorability at time of testing
- Old items are semantically encoded
- New items are episodically encoded
- There is a gradient
Matching for memorability at time of occurence
- All items were had a medium amount of memorability
- Old and new items were encoded the sme amount
- NO TEMPORAL MEMORY GRADIENT
Is there a temporal gradient for episodic memory?
No.
When you control for the saleince or memorability of the events you are asking Korsakoff patients about. It shows that there is no temporal gradient for episodic memory.
Define the standard model of consolidation in terms of the temporal gradient
Time-limited temporal gradient for both episodic and semantic memory
What is the multiple trace theory?
- Hippocampus always necessary for retreival of episodic memory
- Semantic memory becomes stronger over time
What is one possibility that concerns why episodic memory is always dependent on the hippocampus?
The hippocampus is critical for imagining experiences
- old and new
The hippocampus is essential for the
RE-EXPERIENCING of episodic memory
Describe the relationship between episodic memory and imagination
Episodic memory and imaginging or reconstructing events share similar processes
- Imagery
- Sense of presence
Both episodic memory and imagining involve the salient vizualization of an experience within a rich spatial setting or context
What experiment was conducted to examin the relationship between the himpocampus and imagination
“Imagine you’re lying on a white sandy beach in a beautiful tropical bay”
Experimenters assessed their ability to imagine
What are the conclusions made concering hippocampal amnesics and imaginability?
1) Hippocampal amnesics have a deficir in richly imagining new experiences
2) Role of hippocampus extends beyond reliving past experiences, encompassing the construction of fictious experiences
3) Absence of this function may fundamentally affect the ability to re-experience or reconstruct past events
Describe frontal lobe amnesic patients
Frontal patients display relativley intact anterograde memory
However, they have a mild decrement due to need for strategic retreival processes
Describe Temporal Ordering task given to frontal lobe amnesic patients
- How are these kinds of tests conducted?
- What are the experiment results?
3 part experiment:
Subjects given a list of 15 words to study, and then asked to reproduce the list order from random array of words.
1) Word recall = slightly impaired
2) Word recognition = intact
3) Word sequencing = significantly impaired
Describe the Memory for Frequency of Occurerence task
- How are these kind of tests conducted?
- What are the experiment results?
Shown a series of designs
- Decided whether they were composed og straight lines, curved lines, or both
Each design was presented a certain number of times ranging from1-9
- Later aksed to asses how many times each design had occured
Results:
- Once subjects hit the threshold of 3, everyone’s performance seemed to flatline.
- Underestimate the amount the amoutnf of times that a design was seen
- The frontal amnesic patients were particularly impaired
Describe the Source Memory task
- How are these kind of tests conducted?
- What are the experiment results?
- What are the two kinds of source errors associated with this task?
Learned 20 trivia facts that they didnt already know
- Ex. “The name of the dog on the Cracker Jacks box is Bingo”
One week later, given a cued recall test for the 20 learned facts and 20 other facts
- Ex. “What was the name of the dog on the Cracker Jacks box?”
When answered correctly, asked to recollect source of the infromation
Extra-Experimental Source Error
- Recalled learned fact, but said it was from another source
Experimental Source Error
- Recalled other fact, but said it was from the learning source
Results:
Frontal lobe patients were specifically impaired, and had the most source errors in comparison to controls
Define Metamemory
Awareness of one’s memory capabilities, and knowledge about strategies that can aid memory
Describe the Metamemory task
- How are these kind of tests conducted?
- What are the experiment results?
Given 24 scentences to learn
Patti’s garden was full of marigolds””
Cued Recall Test
- “Patti’s garden was full of ___”
Feeling of Knowing
- Rate on 4-point scale of likelihood of recognizing answer
Recogntition test
- Coorelate performance with feeling of knowing ratings
Results
- Frontal lobe amnesics after a 5 minute delay are significantly impaired in comparision to controls. (controls after 3 days = amnesic patients after 5 mins)
- When memory was strong for both subject groups
- Frontal patients were signigicantly impaired on predicting whether they would get it on the recognition test
Define Memory in Healthy Aging
Age-associated memory impairment resembles milder form of frontal lobe memory impairment
Give and example of a task with which age-associated memory impairment subjects would be impaired
Source Error task
What experiment was conducted on older patients to study their aging and impaired inhibitory processes
- Describe the procedure?
Selective Attention Paradigm
- Tones presented at irregular interval
- 30-minute radio show of a story
Told to either
- Ignore tones and listen carefully to story
- Attened to tones and ignore the story that will play in the backround
All while their skin conductance orienting response is being studied
Describe the experiment results of the Selective Attention Paradigm used on older patients to study their impaired inhibitory processes
Results of the skin conductance test indicated that older adults did not attenuate to the tones, whereas younger adults did
Describe the tests given to older patients to asess their memory for frequency of occurence
Ideograms Study
Novel stimuli shown 0 to 6 times
- Ideograms
Later given pairs of stimuli
- Asked which item was seen more frequently
Results:
- Impaired at discriminating how many times they saw an item similar to frontal lobe amnesic patients
Mere Exposure Study
- Repeated exposure leads to higher ratings on ‘likeability scale’
- Novel ideo grams presneted either 1,3, or 9 times
- Asked how much they like the items
Results
- Impaired explicit but not implicit memory for frequency
Describe the relationship between False Memory and Frontal Lobe Function in older subjects
- Subjects read a list
- Given a recognition task containing a target word that is strongly associated with some of the words on the list
- They remeber seeing the target word on the list low frontal lobe function =
Older adults with high frontal lobe fucntioning = look just like younger adults
Older adults with lower frontal lobe functions are impaired on overall recognition for studied items.
Declines in vertical memory and increases in false memory are not inevitable consequences of aging
