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NEUR 2600 Lecture Notes - California Sea Hare, Eric Kandel, Axon Terminal


Course Code
NEUR 2600
Ian Whishaw

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Long Term Memory
Eric Kandel
Binds to calmodulin, binds to vesicles releasing some from filaments and inducing others to bind to the
presynaptic membrane and to empty their contents.
Calcium = ion, carries 2 charges voltage sensitive channels on neuron terminals
"Without memory we would be nothing"
Ways a couple pounds
Have orgies.
Aplysia - california sea slug
Runs the circuitry in its gill
Behavior = gill retracts when touched
Abdominal ganglia = 20 000 neurons
100, 000 neurons
Wrote "In Search of Memory"
Eric Kandel
Horses weren't designed for humans
How do we get them to get used to us?
Given that a particular stimulus elicits a response, repeated applications of the stimulus results in
decreased response
If the stimulus is withheld, the response tends to recover over time (spontaneous recover)
If repeated serious of habituation training and spontaneous recovery are given, habituation becomes
successively more rapid
Other things being equal, the more rapid the frequency of stimulation, the more rapid and/or more
pronounced is habituation
The weaker the stimulus, the more rapid and/or more pronounces is habituation. Strong stimuli may
yield no significant habituation
The effects of habituation training may proceed beyond the zero or asymptotic response level
Habituation of response to a given stimulus exhibits stimulus generalization to other stimuli.
Define: the response to a stimulus weakens with repeated presentation
Gill withdraws from water jet
With habituation, the influx of calcium ions in response to an action potential decreases
Resulting in less neurotransmitter released at the presynaptic membrane
Should follow the same rule: if you come back the next day, should be
letting calcium back in
If you do it repeatedly over days, better effect
Calcium does follow the behavioral rules
Molecular basis of habituation
A lot of small stimulation given rapidly = better
Study this calcium channel and its changes
Conclusion: withdrawal response weakens with repeated presentation of water jet
(habituation) owing to decreased Calcium influx and subsequently less
neurotransmitter release from the presynaptic axon terminal.
And less depolarization of the postsynaptic membrane
Results: the sensory neuron stimulates the motor neuron to produce gill withdrawal before
Gill no longer withdraws from water jet demonstrating habituation
QUESTION: what happens to gill response after repeated stimulation?
Probably another nobel prize in here
Probably one of the things like the alpha, beta, or other protein molecules, repeatedly activated,
loses its function
Complex calcium channel: measuring whether channel was narrower
What we don't know: What is it about the calcium channel that's changing?
One of the features of autism is that individuals do not like stimulation including touch, lights or
sounds - suggesting an impairment in habituation
Addiction - food, drugs, etc
Kindling - epilepsy
Results: an interneuron receives input from a shocked sensory neuron in the
A single shock to the tail enhances the gill-withdrawal response
Se aslug
What is the neuron basis?
An enhanced response to a stimulus
The Cellular Basis of Learning
11:00 AM
Brain and Behavior Page 1
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