Hierarchical Organization of Memory

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Introduction—the basics of psychological learning and memory theory. From Mechanisms of Memory by J. David Sweatt, Ph.D.

Definitions Learning: The acquisition of an altered behavioral response due to an environmental stimulus. Memory: The processes through which learned information is stored. Recall: altered

The conscious or unconscious retrieval process through which this behavior is manifest.

Sensitization in the Venus’ Flytrap

Image courtesy of Muriel Weinerman, New York Botanical Gardens

Vernalization

Cabbage – biennial plant Courtesy Richard M Amasino, U Wisconsin

Arabidopsis thaliana

Subdivisions of Human Memory HUMAN MEMORY DECLARATIVE (EXPLICIT) FACTS

NONDECLARATIVE (IMPLICIT)

EVENTS PROCEDURAL (SKILLS AND HABITS)

PRIMING

SIMPLE CLASSICAL CONDITIONING

NONASSOCIATIVE LEARNING

EMOTIONAL SKELETAL RESPONSES MUSCULATURE

MEDIAL TEMPORAL LOBE

STRIATUM

NEOCORTEX AMYGDALA

CEREBELLUM

REFLEX PATHWAYS

Milner B, Squire LR, Kandel ER: "Cognitive neuroscience and the study of memory". Neuron 1998, 20:445-468.

Hierarchical Organization of Memory Unconscious Learning Storage (unconscious)

Subject to conscious Recall

• • •

• •

Trace conditioning Operant conditioning Hippocampusdependent contextual fear conditioning Taste learning Conditioned taste aversion

Unconscious Recall

Conscious Learning Storage (unconscious)

Subject to conscious Recall

Working Memory

Conscious Storage and conscious recall

•Declarative Learning •Spatial Learning •Conscious associative conditioning

Non-associative learning •Habituation •Sensitization •Dishabituation

Associative Learning •Pavlovian Conditioning •Delay Eye-blink conditioning •Cued Fear conditioning

Motor learning

Aplysia californica

Image courtesy of Dr. John Byrne

Dr. Eric Kandel Nobel Laureate, Columbia University

Aplysia Sensitization

Image courtesy of Dr. Terry Walters

Response

Simple Forms of Learning

The Graded Nature of Learning

Kandel ER: "The molecular biology of memory storage: a dialogue between genes and synapses". Science 2001, 294:1030-1038

Protein Synthesis Inhibitors Disrupt Long-term Memory Consolidation

Training

Control

Inhibitor

Testing at 24 Hrs.

Control

Inhibitor

Vianna MR, Szapiro G, McGaugh JL, Medina JH, Izquierdo I: "Retrieval of memory for fear-motivated training initiates extinction requiring protein synthesis in the rat hippocampus". Proc Natl Acad Sci U S A 2001, 98:12251-12254

Ivan Pavlov with his canine subjects

Image courtesy of Johns Hopkins Medical Institute

Pavlovian Associative Conditioning Conditioned Stimulus Unconditioned Stimulus Unconditioned Response

Conditioned Stimulus Conditioned Response

Categories of Associative Conditioning Delay Conditioning US CS Time

Trace Conditioning CS Time

US

Fear Conditioning TRAINING

•Animal is placed in novel context •Hears a tone •Receives foot shock CONTEXTUAL TEST

•Animal is returned to same context •Test for freezing behavior

CUED TEST

•Animal is placed in modified context •Hears a tone •Test for freezing behavior

Hermissenda

Image courtesy of Mike Johnson

Lifelong Single-trial Learning

Taste Learning NEOPHOBIA

?

DAY 1 10’

DAY 2 10’

TASTE AVERSION DAY 1 10’

LiCl DAY 2 10’

Measure increased consumption Measure decreased consumption as index of long-term memory as index of long-term memory of novel taste of novel taste

Conditioned Taste Aversion DAY 1

B 1.0

1st Exposure to Food Item

Injection of LiCl or NaCl

DAY 2

grams blueberry bar

A

0.8 0.6 0.4 0.2 0.0

LiCl

NaCl

Grams Ingested on 2nd Exposure 2nd Exposure to Food Item

(LiCl treated group compared to NaCl treated control)

Neophobia DAY 1

B 0.8

1st Exposure to Food Item

grams blueberry bar

A

0.6 0.4

DAY 2

0.2 0.0

1st intake

2nd Exposure to Food Item

2nd intake

Grams Ingested (1st exposure compared to second exposure)

Non-graded Acquisition of Memory

Four Types of Experiments

Hypothesis: A→B→C Experiment

• • • •

Determine Block Mimic Measure

Prediction

• • • •

None (A makes C happen) Blocking B should block A causing C Activating B should cause C A makes B happen

The World’s “Deadliest” Marine Animal

BOX Jellyfish Sea Wasp Species - Chironex Fleckeri

Synonyms - Box Jellyfish, Fire Medusa, Indringa. The Box Jellyfish projects pedaliums, each of which may contain up to as many as fifteen tentacles each 3 metres in length

For mobility, the Box Jellyfish contracts with a jet-like motion, shooting itself along up to speeds of 4 knots. It is presumed to have “eyes” connected to a nerve ring and the creature can take evasive action or move towards its prey.

Nematocyst (400X) ~4000/animal

The World’s Deadliest Marine Animal