Lecture 19: Synaptic Plasticity

Short term plasticity

Changes in neurotransmitter release

Long term plasticity

Changes in gene transcription, protein synthesis and trafficking of receptors into/out of the membrane

Associative learning

• Repeated exposure to a stimulus

• Learn something new about that stimulus

• Conditioning

Non-associative learning

• Repeated exposure to a stimulus

• Stimulus meaning desnt change

• Habituation and sensitization occurs

Habituation

Reduction of response to a stimulus

Sensitization

Increase in response to a stimulus

Sensitization study

Cocaine increasing locomotor behavior from day 1 to day 8

Sensory memory

Stored for a few seconds and lasts for the duration of the stimulus

Short-term/Working memory

Stored for minutes/hours, involved in day-today tasks requiring cognitive effort

Long term memory

Can be stored for hours or years

Two types of declarative (long term memory

Semantic and episodic

Semantic memory

Facts, data, events

Episodic memory

Personal events/stories

Procedural memory

How to do tasks

What does the transition from short term to long term memory require?

Attention, strength of experience and number of experiences

Short term potentiation effect on synaptic strength

Increase

Short term depression effect on synaptic strength

Reduce

Long term potentiation effect on synaptic strength

Increase

Long term depression effect on synaptic strength

Reduce

Short term depression and long term depression have what similar effect?

Sensitization

Short term potentiation and long term potentiation have what similar effect?

Habituation

Amygdala function in learning?

Modulatory

• Provides emotional context

Prefrontal Cortex function?

Modulatory

• Maintain internal representation of tasks

• Focus attention

Thalamus learning function

Modulatory

• Regulates cortex activity

• Contributes to attention

Cerebellum function in learning

Procedural memory

• Trial and error

• Coordination of movements

Striatum function

Modulatory

• Underlies associative learning

• Contributes to procedural memory

Peforant pathway of memory modulation

Dentate gyrus → CA3 → CA1 → Subiculum

The perforant path is filled with

Glutamatergic neurons

Memories are stored in a single location or something else?

Something else, engrams

CAN I GET A WOOHOO

WOOHOO

Neurons differ in their…

• Excitability

• Firing Rate

• Connections

Fuster and Jervey experiment

A delayed matching-to-sample task on monkeys

What was measured in Fuster and Jervey?

Individual neurons in the inferotemporal cortex of image recognition

What were the findings of Fuster and Jervey?

Short-term/working memory is encoded by sustained spiking PATTERNS of localized neurons

Drosophilia amn mutation caused impaired retention. What was it?

It decreased a neuropeptide modulator of adenylate cyclase

Drosophilia rut mutation caused impaired retention. What was it?

Impaired adenylate cyclase

Drosophilia dnc mutation caused impaired retention. What was it?

Impairment of cAMP phosphodiesterase