Transcript Learning & Memory

Learning & Memory
Behavioral and Cognitive Neuroanatomy
http://zlab.rutgers.edu/lzclasses.html
Sean Montgomery - TA
[email protected]
The Brain Does 3 Things
- Sensory Input
- Integration
- Behavioral Output
Philosophy of Memory
- Encoding
- Acquisition
- Consolidation
- Storage
- Retrieval
Experimental Subdivisions of
Memory
• Sensory Memory
• Short-term (working) memory
• Long-term memory
Sensory Memory
Short-term (Working) Memory
Transfer from Short- to Long-term
Memory
The Modal Model
By Atkinson & Shiffrin
Double Dissociation of Short-term
and Long-term Memory Machinery
Patient E.E. has damage to
the left angular gyrus
causing a deficit in shortterm, but not long term
memory
Patient H.M. had damage to
the medial temporal lobe
causing a deficit in longterm, but not short-term
memory
Long-term Memory
(a little history)
- Behaviorist’s view that all learning
could be constructed from simple
stimulus-response associations
- Tolman showed that animals could form
stimulus-stimulus associations or internal
cognitive maps
COGNITIVE MAPS IN RATS AND MEN[1]
Edward C. Tolman (1948)
First published in The Psychological Review, 55(4), 189-208.
Modern Breakdown of Memory
Patient H.M.
H.M. Can Learn New Skills
- Mirror Tracing
- Incomplete Picture
Identification
Patient M.S. Has a Deficit in
Perceptual Priming (implicit memory)
Patient K.C. Can Acquire Semantic,
but not Episodic Memory
Consolidation of Memory
Korsakoff’s Syndrome
PET Imaging
Animal Models of Amnesia
Animal Models of Memory
What is declarative memory in a species that can’t talk?
- Some investigators hypothesize that declarative memories involve complex
representations of relationships between different aspects of the memory
Episodic Memory
soft
Semantic Memory
flannel
left
metal
Walk down street
wearing shirt
saw
woman
hair
purse
bat
hit
screamed
loud
bases
round
leather
stitching
man
took
woman
runs
ball
old
blue
red
red
swings
wood
foot
hurts
batter
Baseball
throws
pitcher
catches
fielder
glove
Relational Memory in
Rodents Depends on
the Hippocampus
Spatial Memory is Relational in
Nature
Spatial Memory Task
Transverse Patterning Task
Spatial Tasks Require the
Hippocampus
Spatial Water Maze Task
Requires the Hippocampus
Non-Spatial Water Maze Task
Doesn’t Require the Hippocampus
Double Dissociation of Spatial Vs.
Stimulus-Response Learning
- Using a spatial strategy requires an
intact hippocampus
Probe Start
TurnResponse
Strategy
Place
Strategy
- Using a response strategy requires an
intact dorsolateral striatum
- Early in training animals use a place
strategy
Reward
- Late in training animals use a turnresponse strategy
Start
Cellular Basis of Learning
Hebb’s Law
- If a synapse is active when a postsynaptic neuron is active, the
synapse will be strengthened
i.e. Cells that fire together, wire together.
• Cooperativity
More than one input must be active at the same time
• Associativity
Weak inputs are potentiated when paired with stronger inputs
• Specificity
Only active synapses are potentiated
Hebb’s Law
• Cooperativity
Without cooperativity new memories can’t
be formed.
Those presynaptic cells that can fire the
post synaptic cell will continue to do so
and those that cannot fire the post
synaptic cell will never be able to.
A
B
Hebb’s Law
• Associativity
A
B
Before Pairing
Hebb’s Law
• Associativity
A
B
Pairing
Hebb’s Law
• Associativity
A
B
Pairing
Hebb’s Law
• Associativity
A
B
After Pairing
Hebb’s Law
• Specificity
A
B
Before Pairing
Hebb’s Law
• Specificity
A
B
Pairing
Hebb’s Law
• Specificity
A
B
After Pairing
Molecular Basis of Learning
Molecular Basis of Learning