CCC- Amnesia Flashcards
What is Amnesia?
Amnesia is a general term that describes memory loss. The loss can be temporary or permanent, but ‘amnesia’ usually refers to the temporary variety.
Ability to take in new information is severely & usually permanently affected.
Intelligence is intact
Attentional span is intact
Personality is unaffected
What is not affected with Amnesia?
Intelligence is intact
Attentional span is intact
Personality is unaffected
Who was HM studied by?
What was wrong with him?
(Scoville & Milner, 1957)
What was wrong with HM?
Underwent surgery for the treatment of severe epilepsy
Completely lost his memory for events after surgery
Could not recall ever having met the specialists he had been talking to after they left he room for a few minutes
Anatomy of Amnesia
When HM underwent surgery, what was removed/ where was the damage ?
HM’s surgery removed parts of his medial temporal lobes
Included the “hippocampus”
Amnesia is usually caused by damage to the medial temporal lobe or connected regions
Can occur in head injuries, Alzheimer’s disease, epilepsy, stroke
What does Anterograde mean?
After brain injury?
What type of Amnesia did HM have?
Anterograde amnesia
What is anterograde amnesia?
Anterograde amnesia (AA) refers to an impaired capacity for new learning.
How was HM tested- was he impaired in all the tests?
HM was severely impaired no matter what kind of memory test was given (Corkin, 2002)
words, faces, tones, public events, etc
Regardless of test format (free recall, cued recall, recognition)
What test is used for visual memory?
Rey Complex Figure test
What do patients do on the Rey Complex Figure test?
Presented with a figure- e.g. line drawing & asked to copy it.
After a brief delay, they are asked to reproduce from memory what they had copied previously.
The patients with damage to their medial temporal lobe- were unable to copy the picture very well- they mixed up where things were.
Controls- did well for the same test.
Anterograde Amnesia
What did they do in the recognition memory test for faces?
Patients would be given a test where they are exposed to new information/ faces/ words one after the other.
They are then asked questions about the faces- e.g. does the face look pleasant/ unpleasant?
After they have seen the list of faces, they are given the choice between 2 faces & have to pick out the faces they have seen.
Main test- 50 faces.
New learning- anterograde amnesia
What tests are normally used?
Tests of learning may use a recall or a recognition format
Typically use both verbal and visual tests
Relatively large number of items (many more than can be stored in working memory)
Test after a delay (typically of a few minutes) (see how well they can bring the memory back into working memory)
Patients with anterograde amnesia impaired on all tests
What memory systems are not affected for amnesic patients?
Working memory is intact- verbal & visual short term memory.
They have long term memory impairment.
Digit span
Repeat the numbers “2…7…4…9…2…8”
Spatial span
Tap the same blocks as me, in the same order
What other memory systems are not affected for amnesic patients?
Procedural memory
Amnesics can learn new skills
Mirror tracing (Corkin, 1968)
Also weaving, controlling a joystick, mirror reading, etc.
Procedural memory- HM example?
Want to teach patients new things- trace around a shape- e.g. star but can only look in the mirror.
Practise & become good at tracing the shapes.
At start- HM makes lots of errors- gradually becomes better over time.
After 3 days- makes very few errors.
He shows the same degree of learning skill as normal people.
He doesn’t remember the training sessions- but can demonstrate learning new skills.
What did Elizabeth Warrington study?
Priming
- degraded picture identification.
- 5 amnesic patients.
Used pictures degraded in a sequential way.
First- shows pictures (at bottom of sheet (don’t clearly look like object)- then go up the sheet (progressively show more information) - and get patients to guess what the pictures are.
After a few trials- patients get better.
Amnesic patients were learning at the same rate as those without brain damage.
Priming- ability to change your response to something- even if you don’t explicitly remember where you saw the information before.
What is priming/ the priming effect?
Who studied this?
Elizabeth Warrington
Occurs when an individual’s exposure to a certain stimulus influences his or her response to a subsequent stimulus, without any awareness of the connection.
What does declarative memory theory break long term memory into?
Long term memory is not a single store and has two components.
Declarative (conscious) memory- broken down into:
- Episodic (personal events
- Semantic (Facts, knowledge)
Implicit (not conscious)
- Priming effects
- Procedural memory
Declarative memory theory
For amnesic patients- what component of memory is affected?
Declarative (conscious memory)
Declarative memory theory
What is not affected for amnesic patients?
What does this suggest?
Implicit (not conscious) memory
- priming effects
- procedural memory
Suggests there are different neural substrates in the brain.
What did Tulving 1972 propose?
Episodic & semantic memory is different.
E.g. if ask patient with amnesia what they ate for breakfast- they won’t remember!
If ask patient.
What did Squire 1982 argue?
Argued amnesia as a loss in the ability to form any new “declarative memories”
Can amnesics acquire new semantic memories?
No & yes
Acquiring new semantic memories
What did Bayley et al 2008 test?
Bayley et al., (2008) tested new vocabulary in 2 adult amnesics
Each test item contained one target word (e.g., Prozac) and eight foil words (e.g., Flozac, Prozam, Grodaz, etc).
Results- both slightly above the line ( line is if completely guessing) on the graph- however- nowhere near the healthy controls.
Shows theres no learning of semantic declarative memory- who have amnesia.
When can amnesic patients acquire new semantic memories?
Beth, Jon and Kate are typical amnesics (Vargha-Khadem et al., 1997)
They sustained damage to the hippocampus just after birth
Have grossly impaired episodic memory
BUT, they completed normal schooling, have good vocabularies and knowledge about the world
They have a well developed semantic memory store- despite having bad episodic memory.
Implications for declarative memory
What did Squire say amnesia is?
What evidence contrasted this?
Squire characterised amnesia as a loss in the ability to form any new “declarative memories”
Evidence that Beth, Jon and Kate could acquire semantic memories is evidence against that.
But – perhaps memory processes in their brains are unusual as their brain damage occurred so early in life?
Implications of declarative memory
Beth, Jon and Kate are typical amnesics (Vargha-Khadem et al., 1997)- why may they have differences in their ability to learn new semantic memories?
Individuals sustained damage very early in lives after birth- gave capacity for brain to adapt to the damage- so not looking at effect for normal healthy brain that then acquired brain damage- this may explain the differences.
What does retrograde mean?
Retrograde means before brain injury.
Some retrograde memory loss is almost always present in amnesia
What is Retrograde amnesia?
Retrograde Amnesia: Describes amnesia where you can’t recall memories that were formed before the event that caused the amnesia. It usually affects recently stored past memories, not memories from years ago.
What was HMs retrograde memory for famous people like?
Generally good.
Retrograde amnesia- HM
How well did he do when he was tested on faces from the 1940s/ 30s compared to the 1960s?
Did poor at remembering faces from the 1960s.
Did better when remembering faces from 40s/ 30s- He was able to recognise the faces as well as healthy adults.
Standard theory of consolidation- what is this?
Has been summarized by Squire and Alvarez (1995); it states that when novel information is originally encoded and registered, memory of these new stimuli becomes retained in both the hippocampus and cortical regions.
What does the standard theory of consolidation suggest?
Previously thought- hippocampus binds information throughout the brain & when we retrieve information- we need to hippocampus to reactivate the information.
However- evidence from e.g. HM has found that information still binds together- however not in the hippocampus & medial temporal lobes- we don’t need them to experience these memories.
This is because HM had good memories for things that happened in the past- so logically don’t need this system as for HM- the system wasn’t working properly!
What was Warringtons 1966 issue with how people were testing memory?
Argued that tests often used highly familiar photos of people- e.g. Elvis, Marilyn Monroe ( we all would recognize these photos as they are in everyday usage)
Instead- should be using faces of people equally memorable across time periods who were alive at the specific periods they could remember- however if not alive at that time, you will likely not remember them.
What are the results in Warringtons way of testing healthy controls & amnesic patients?
Healthy controls- better for recognizing people currently famous & well known- get worse when recognizing faces further back in time- still able to recongise a few however.
They do consistently better than the amnesic patients who have impaired memory throughout- and even have memory impairments for things that should have been consolidated according to “Standard theory of consolidation”
What is Multiple Trace Theory?
Morris & Lynn
Every time a memory is retrieved, it is re-encoded and a new set of connections (trace) between the hippocampus and the cortex is made
In Multiple Trace theory- what happens?
Claims that the hippocampus is always required no matter the age of the memory.
Over time- memories get more and more linked up with the hippocampus and cortex - so always need hippocamous to remember episodic memories. If you are able to generate episodic memories for things throughout your life- you always will require the hippocampus & cortical brain areas to remember the event.
What are the two contrasting theories?
Multiple Trace Theory & Standard Theory of Consolidation
Standard theory of consolidation VS multiple trace theory
Who is right? What evidence is there?
No consensus about who is right
Evidence to support both theories
from functional MRI as well as patient studies
Perhaps memories are transformed over time
If a memory becomes part of your general knowledge it isn’t affected by amnesia caused by medial temporal lobe damage
But to vividly recall a memory, you might always need you medial temporal lobes
What is semantic memory?
Conceptual knowledge about the world.
Includes:
knowledge of the meaning of words, objects and other stimuli perceived through the senses
facts and associated information
How can you test semantic memory?
Memory association tests e.g. Howard & Patternson, 1992
Pyramids and Palms Trees test of semantic knowledge
E.g. picture of a pyramid at the top
Picture of two different trees at the bottom
Have to choose which tree you would put with the pyramid.
(Test is good as you don’t have to generate a verbal response)
What is semantic dementia?
Difficulty in remembering the meaning of words or concepts (lose concept of the knowledge)
Naming errors (e.g. “dog” for rabbit).
Problems not confined to a single modality
May include a difficulty in recognizing sounds (e.g. doorbell or telephone)
Semantic dementia scan
What would you see?
Atrophy in temporal lobes & lateral areas-
Lateral temporal cortex- particularly associated with semantic dementia.
What are frontal lobes important for?
The frontal lobes are important for the strategic aspects of memory
Searching for the right memory
Checking and verifying the memory is correct
Does it fit with the current situation?
What is confabulation?
Confabulation is a type of memory error in which gaps in a person’s memory are unconsciously filled with fabricated, misinterpreted, or distorted information.1
When someone confabulates, they are confusing things they have imagined with real memories.
What are provoked confabulations?
People come up with something that isn’t true because they don’t know what the answer is
What are spontaneous confabulations?
Spontaneous confabulation is a profound derangement of thought in which the patients’ ongoing reality and planning are dominated by their past experiences and habits.
So, confabulations are the patients’ honest view of their perceived reality, and therefore lead them to act in accordance with mistaken beliefs.
What is spontaneous confabulation caused by?
Usually a result of frontal lobe damage
Not due to damage to memory storage
Caused by a breakdown in memory “executive processes” such as monitoring whether retrieved memories are relevant to now
