Learning & Memory Sean Montgomery - TA Behavioral and Cognitive Neuroanatomy

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 short- term, but not long term memory Patient H.M. had damage to the medial temporal lobe causing a deficit in long- term, but not short-term memory

Long-term Memory - 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 (a little history) COGNITIVE MAPS IN RATS AND MEN[1] Edward C. Tolman (1948)1 First published in The Psychological Review, 55(4),

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 Walk down street foot wearing shirt left hurts flannel red soft saw woman hair blue man took purse red woman old screamed loud Semantic Memory Baseballball round leather stitching bat wood metal hit pitcher throws batter swings bases runs fielder glove catches

Relational Memory in Rodents Depends on the Hippocampus

Spatial Memory is Relational in Nature Transverse Patterning Task Spatial Memory 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 Start Reward Probe Start Place Strategy Turn- Response Strategy - Early in training animals use a place strategy - Late in training animals use a turn- response strategy - Using a spatial strategy requires an intact hippocampus - Using a response strategy requires an intact dorsolateral striatum

Cellular Basis of Learning

Hebb’s Law Cooperativity Associativity Specificity - If a synapse is active when a postsynaptic neuron is active, the synapse will be strengthened i.e. Cells that fire together, wire together. More than one input must be active at the same time Weak inputs are potentiated when paired with stronger inputs 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 Before Pairing A B

Hebb’s Law Associativity Pairing A B

Hebb’s Law Associativity Pairing A B

Hebb’s Law Associativity After Pairing A B

Hebb’s Law Specificity Before Pairing A B

Hebb’s Law Specificity Pairing A B

Hebb’s Law Specificity After Pairing A B

Molecular Basis of Learning