LEC 11: MEMORY Flashcards
What is memory?
- Connecting 2 stimuli (ex: classic conditioning Pavlov)
- Processing involved in retaining, retrieving, and using info abt stimuli, images, events, ideas, and skills are the original info is no longer present.
How are diff kinds of memory distinguished?
By how long info is retained
What are the three kinds of memory?
sensory, short term (working memory), long term
Who is Henry Molaison?
- Patient who lost long-term memory after surgery for epilepsy after the medial temporal lobe was removed
- anterograde amnesia
anterograde amnesia
inability to form new memories
retrograde amnesia
- an inability to retrieve info from one’s past
(except for some temporally-graded retrograde amnesia)
temporally graded amnesia
- info acquired in the distant past (remote memory) is spared relative to more recent memory
- for ex: 50 yo patient with recent amnesia from head trauma might maintain normal memories of his life until he was abt 40, but might have memory issues affecting yrs 41-50, w worsening memory closer to time of amnesia -causing injury at 50
- thus thee extent of amnesia differs (ex: is graded) over time
HM had no change in
- IQ or language abt
- indicates impairment is specific to memory but no cognition generally
Could HM learn new things
YES!
- skill learning, visual & perceptual skills thru exposure or repetition
Mirror-drawing task
- follow the outline of an obj where all visual guidance is through a mirror
- HM was able to build this skill even though he does not remember does the skill previously
Word-stem completion task
- task in which participants are asked to fill in the blanks in list of word stems (ex: MOT__) to produce first word that comes to mind;
- in a priming experiment, participants are more likely to produce particular word (ex: MOTEL) if they have been exposed to that word previously
even amnesics like HM
Consolidation
- the process by which memories become stable in the brain
- heavily reliant on MTL
Working Memory
ability to hold limited amount of info active and manipulate it
- limited in capacity
- short term
What was HM’s working memory like?
Normal range
Korsikoff’s Disease
Cortical damage of alcoholism, delete/damages long term declarative memories
Strokes: Ischemic
- a blood clot cuts off the blood supply to the brain
- can damage hippocampus and impair LTM performance
The neurobiology of memory (7 structures)
- Hippocampus
- Parahippocampus
- Entorhinal cortex
- Perihinal cortex
- Dentate gyrus
- Subiculum
- Amygdala
Where do the brain regions converge in the hippocampus
Entorhinal cortex: important for integration and learning
Neurons that fire tighter…
wire together!
Two types of glutamate receptors
AMPA: has excitatory function –> makes postsynaptic cells more likely to fire
NMDA: has mg ion that only opens when post-synaptic neuron is already depolarized
NMDA receptor activation
- lets calcium ions into cell
triggers:
- short term: produce AMPA receptors in synapse –> more opportunities to out sm excitatory
- in the long term: create whole new synaptic terminals
NMDA is sensitive to
- coincidence: a mechanism is sensitive to 2 things happening at the same time
After learning, you develop more
- AMPA receptors
- making postysynaptic neuron more likely to fire
where is working memory supported in the brain
- dorsolateral prefrontal cortex (DLPFC) impairs performance on memory tasks involving short delay
