Eric Kandel: Synaptic Changes

in the Hippocampus

Johnia MurrayImani Ross

IB Psychology II1A

Kandel was a pioneer in moving the study of

the mind from an investigation of behavior to an investigation of impulses

Deals with learning and memory in the hippocampus of the brain

Memories don’t reside in a single, specific spot of the brain

Neural (neurons->synapses->impulses) change occurs between the synapses

Background Info

What is this?

Sites at the end of a neuron Place where nerve cells communicate with one

another Use neurotransmitters as messages to each

other

Synapses

1982 Experiment

Eric Kandel and James Schwartz Observing changes in sending neurons Used a California sea snail, the Aplysia

Getting Down to Specifics. . .

A California Sea Snail Observed changes in sending neurons Has 20,000+ unusually large nerve cells Classically conditioned (Ch. 8 from last year)

the snail to withdraw its gills when water is squirted at it

Learning occurs Snail releases serotonin at certain synapses

Becomes more efficient at transmitting signals

Aplysia Study

NOVAscienceNOW – A Memorable Snail - PBS http://

www.youtube.com/watch?v=yLa-cXg8BwM

Aplysia Study cont’d

Increased synaptic efficiency makes for a more

efficient neural circuit Sending neurons now need less imprinting to

release neurotransmitters The receiving neuron receptor cites may increase Long Term Potentiation

a long-lasting strengthening of the response of a postsynaptic nerve cell to stimulation across the synapse that occurs with repeated stimulation and is thought to be related to learning and long-term memory

Synapses and Memory

LTP provides a neural basis for learning and

remembering associations (reference to Ch.8) Drugs that block LTP, interfere with learning At least 40 cognitive enhancers are currently

in some phase of development or clinical trial Target market: those with Alzheimer’s Disease,

with mild cognitive impairment

Synapses and Memory cont’d

Hippocampus: Where is it located?

Where initial events must come here in order

to be turned from short term to long term memory

Short term memory is processed in the hippocampus

Neurons have to cross over the synapses to leave a mark or ‘tag’

Declarative Memory A memory for fact and events

People, places and objects

Hippocampus

Contains a cognitive map of external

environment Registers spatial information

Space surrounding you (or animals) Registers single sensory modality

Sight, sound, touch or pain

Hippocampus cont’d

Synaptic changes affect our learning ability

and memory Memories are stored in different places A lot of work is done in the hippocampus Don’t do drugs Snails are more than just slimy creatures that

look nasty There’s still a lot to be discovered about the

brain

In short. . .

Myers, David G. (2006) Psychology (AP

Edition). :Macmillan – Worth Publishers. Mayford, Mark; Siegelbaum, Steven A; Kandel,

Eric R. (2012) Synapses and memory storage. CSH Perspectives in Biology, 4(6). Retrieved from http://cshperspectives.cshlp.org/content/4/6/a005751.full

Reference List