Learning from an invertebrate

Aplysia

Advantages: simple nervous system, large neurons, invariant neuralanatomy

Nonassociative Learning

Habituation and sensitization

Neural circuit

Sensory neuron, motor neuron, facilitory interneuron

Changes in amount of transmitter released from SN

With habituation observe a decrease

With sensitization observe an increase

Review: Basic neural function

Resting potential (Na, K)

Action potential

Initiated by depolarizing the cell

Rising phase: Na flowing into the cell

Re-establishing the resting potentiial: K flowing out

Synaptic transmission

Ca channel, vessicles, neurotransmitter

Biochemical mechanisms

Habituation

Inactivation of Ca channels

Short-term sensitization

Biochemical cascade (serotonin, serotonin receptor, G-protein, adenylate cyclase, ATP-->cAMP, protein kinase, K channel, Ca channel)

Increases the duration of the action potential

An addn. biochem. mech. depends on DAG and PKC

Mobilizes transmitter stores and increases Ca current

Long-term sensitization

MAP+PKA engage gene expression via CREB-1 & CREB-2