PSY 241 Lecture 16

• will retract gill when water is squirted into their siphon
• will exhibit habituation

• decrease in response to a stimulus as it is repeated
• form on non-association learning (only 1 stimulus)

Caused by synaptic changes between the sensory cell in the gill - less transmitter released by sensory neuron produces the short term habituatior

• failure of the sensory system to detect the stimulus
• failure of the motor system to repond

• US: Air puff
• UR: Blinking
• CS: Bell
• CR: Blinking after pairing
• Lateral interpositus nucleus (LIP)
• Neurons in the LIP are not responsive to the town presentation in the beginning, but eventually increase their responding as learning

• cells that fire together, wire together
• could act together to store memory traces
• support found in hippocampus

• Electrode within perforant path
• record electrical response of group of postsynaptic neurons (dentate gyrus)

• Normal,low level activation of the presynaptic cells produces table and predictable Excitatory post-synaptic potentaisl (EPSPs)
• Tetanus applied to presynaptic cells, causing them to produce a high rate of action potentials, the response of the postsynaptic neurons changes

Brief high-frequency burst of electrical stimuli

weeks or more

glutamate

block them and you get no LTP

partial depolarization occurs and the NMDA receptor allows calcium to enter in response to glutamate

• Influx of Ca2+ activates intracellular enzymes. causing changes in AMPA receptors:
• Existing receptrs move to the active synapse (increased conductance of ions)
• Activate retrograde signal to increase neurotransmitter release
• Synapses that are not strengthened will become weaker and fade away

Time course of LTP is similar to that of memory formation

• pharmacological treatments that block LTP also impair learning
• Mice pverexpress NMDA receptors have enhanced LTP and better memory

training an animal in a memory task can induce LTP

Tetanus activity necessary to produce LTP is artificial (it is not reproducible in real life)