L18: Memory systems Flashcards
Types of Memory
Declarative memory/Explicit: Memory of facts or events
Usually what people mean when they refer to memory in everyday life
Episodic memory: autobiographical life experiences
Salient memories: Wedding day, Graduation
Semantic memory: facts
Easy to form and easy to forget
Nondeclarative memory/Implicit: type of memory that is learned without conscious awareness
Procedural memory: memory concerned with habits, skills, behaviors
Results from direct experience
Usually require repetition and are harder to forget
Sensory input
Sensory input needs to be processed and given attention in order to create a sensory memory
Stored in sensory cortex (V1, A1 etc.)
Unattended information is lost
Decay
Time window for actively paying attention and remembering something is very short; that trace in the information will decay until it goes away
Interference
If a second thing comes in through the system, it overrides the first stimulus and we can fail pay attention to the first thing that happened
Becomes less likely that we remember the first thing
working memory
mental scratch pad; top of the mind
Maintenance rehearsal - actively rehearsing something to remember it
Repeating phone number in head to remember it
Unrehearsed information is lost
short term memory
memory that is operating on the order of minutes or hours
What you ate for breakfast but can’t remember breakfast from random day earlier
Not very relevant information that needs to be remembered
Unconsolidated information is lost;
susceptible to being “erased”
long term memory
final stage of episodic memory
Can stay indefinitely; childhood memories, family events
Recall pretty well
Reconsolidation - everytime we retrieve a long term memory, it gets altered a little bit
Central Executive
Central Executive - conscious ‘you’; decides where to allocate attention
If you are trying to maintain information Central Executive directs attentional resources to one of the rehearsal processes
Episodic buffer
short term memory; a component of working memory that temporarily stores and integrates information from multiple sources to create a unified memory
Chunking
splitting things into small sections
Prefrontal Cortex Lesions
Phineas Gage
Could not remember basic things/ goals
Anything that needed you to coordinate your behavior for more than a few minutes
PFC assessment
Wisconsin card sorting
Give people a set of cards
The person is supposed to sort the cards by an unknown dimension
Most people with healthy PFC will arrange it correctly, but damaged PFC are often impaired on this task and when you switch the rules of dimensions
Delayed-response task
information is presented to a subject, then withdrawn, and a relatively brief delay interval ensues. The subject is then presented with a choice of two or more response alternatives and is required to choose the one presented previously to obtain reinforcement.
Delayed saccade task
Monkey is trained to fixate on the central point and at some point the target will appear in his peripheral vision.
The monkey is supposed to remember where the target is located without directly looking at it
Has to remember it after a brief delay
Engram/Memory Trace
The group of neurons that serve as the “physical representation of memory”
Distributed network
Memories cannot be held in one single cell; there are multiple cells involved
Neurons that fire together wire together
Donald Hebb
Hippocampus
sits in the medial temporal lobe; folded into the lobe
Henry Molaison (1926-2008)
Bilateral temporal lobectomy
Cut out parts of temporal lobe to help with epilepsy
Anterior ⅔ of hippocampus
H.M. had bilateral temporal lobectomy and anterior ⅔ of hippocampus was taken out
He had debilitating amnesia - had anterograde amnesia
Could not form new episodic memories after his surgery; Procedural memory was intact but not able to encode new episodic memories
Alzheimer’s disease
Shrinkage of hippocampus
Declarative memories go away first
Targets the MTL