learning & memory Flashcards
learning
the process of acquiring information
memory
the ability to store and retrieve that information
patient H.M.
Henry Gustav Molaison (1926-2008)
- Bicycle accident when young led to the development of severe epilepsy
- At 27, surgeon removed parts of his brain in an attempt to stop his seizures
bilateral medial
temporal lobectomy
removal of the medial portions of both temporal lobes, including most of the hippocampus, amygdala, and adjacent cortex
positive results of H.M. surgery
- General convulsions eliminated
- Partial seizure frequency decreased
- Anti-convulsant medication decreased
- No change to perceptual nor motor abilities
- Slight increase in intelligence
consequences of surgery
- mild retrograde amnesia - limited memory of events in the 2 years preceding surgery
- severe anterograde amnesia - difficulty forming some new long-term memories
- profound deficits in long-term declarative memory (explicit)
retrograde amnesia
loss of memories formed before a brain injury
anterograde amnesia
- loss of memory for things occurring after a brain injury
- inability to make new memories
memory tests
- mirror drawing task
- incomplete pictures task
amnesia
severe impairment of memory
types of non-declarative memory
- skill learning (sensorimotor)
- priming
- associative learning
- classical conditioning
- instrumental conditioning
skill learning
** process of learning how to perform a challenging task by simply doing it over and over again
- does not require the medial temporal lobe
- does require the basal ganglia, cerebellum, and motor cortex
priming
** a change in the way you perceive a stimulus, specially because you’ve seen it or something similar before
- associated with reduced activation in the occipitotemporal cortex (word form) or left frontal cortex (word meaning)
associative learning
learning relationships between events
what part of the brain does classical conditioning require?
cerebellum
instrumental conditioning
** learn that a certain action yields a certain consequence
– no consistent brain region identified
- press the lever -> food pellet
poke the nose hole -> get foot shock
classical conditioning
** learning where a person/animal learns to connect two things that happen together
- a bell rings every time food is given, eventually the bell alone can make them expect food
global amnesia
a brief, sudden episode of memory loss that affects the ability to form new memories
scientific contributions from H.M.
- memory functions are NOT diffusely and equivalently distributed throughout the brain
- there are different modes of storage for short-term and long-term memories
- demonstrated a role for medial temporal lobe in memory consolidation
- different mechanisms exist for procedural and non-procedural recall
semantic memory
- general knowledge
(names, dates)
episodic memory
- autobiographical events
(your own experiences)
procedural memory
** long-term memory that helps you remember how to do things, especially physical tasks or routines
- automatic and doesn’t require conscious effort once learned.
ex: tying your shoes/riding a bike
results of delayed nonmatching-to-sample test (monkeys)
loss of the hippocampus, amgydala, and associated cortex in monkeys leads to impairments in object recognition
what parts of the brain are damaged by bilateral medial temporal lobectomy?
hippocampus
amygdala
rhinal cortex
results of mumby box (rats)
only loss of the rhinal cortex in rats showed deficits in object recognition
what disrupts performance in spatial recognition tasks?
bilateral lesions of the hippocampus
examples of spatial recognition tasks
- radial arm maze
- use of cognitive maps
place cells
neurons that respond when a subject is in a specific location in the test environment
sensory buffers/input
fleeting memories/glimpses of a scene that vanish quickly
which part of the brain is important for spatial recognition?
hippocampus
which part of the brain is important for object recognition?
rhinal cortex
working memory (STM)
the ability to actively manipulate information while in short-term memory
short-term memory (STM)
short period of time during which you are actively attending to the information
long-term memory (LTM)
long lasting memories that persist even when you no longer attend to the information
encoding
getting raw sensory information into STM
consolidation
moving info from volatile STM to more durable LTM
retrieval
calling stored information back into working memory (STM) for use
reconsolidation
- from LTM back to STM memories become fragile
**process for updating LTM
about the medial temporal lobe:
- is NOT required to encode sensory info or retrieve the info from STM
- is CRUCIAL for consolidating declarative information from STM to LTM
order of memory processes
- encoding
- consolidating
- retrieval
- reconsolidating
neuroplasticity
changes in the structure & function of synapses that underly learning and memory
long-term potentiation (LTP)
- stable, long-lasting enhancement of synaptic transmission
- cellular mechanism of memory
synaptic plasticity: neurotransmitters
- glutamate
- excitatory NT
- binds to NMDA and AMPA receptors
what is crucial for memory consolidation?
hippocampal LTP
memory storage
**inferotemporal cortex
- visual patterns
** amygdala
-emotional significance of experiences
**prefrontal cortex
- tasks with a series of
responses
**cerebellum
- learned sensorimotor skills
**striatum
- consistent relationships between stimuli and responses
