Anatomy of a Nerve Cell POST-SYNAPTIC NEURON dendrites impulse synapse axon PRE-SYNAPTIC NEURON neurotransmitters

Compare Neurons and Other Cells neurotransmitters axon Cell membrane Nucleus (RNA synthesis) Cytoplasm (protein synthesis) Mitochondria (energy production) dendrites neuron generalized cell

How Nerves Work Pre-synaptic axon Post-synaptic dendrite neurotransmitters receptor synapse impulse --> release neurotransmitters into synapse --> relay impulse to next cell

Making A Memory

Memory: The Long and Short of It impulse cAMP levels PKA activated Existing proteins activated CREB activated New protein synthesis Learning and memory (STM) Memory Only (LTM)

Short-term Memory A weak stimulus produces a short-term memory. What are some short-term memories? dendrites cell body nucleus axon weak stimulus next neuron dendrites cell body nucleus axon weak stimulus next neuron Ca As an impulse travels down the axon it triggers an increase of Ca ++ ions in the cell.

More Short-Term Memory cAMP  PKA  neurotransmitter release AND PKA  Ca ++  prolonged neuron activity Ca cAMP Ca Ca ++ ions  cyclic AMP cAMP activates proteins required for passing signals between nerve cells Short-term memory is the result of a chain of events that activates existing proteins and increases the levels of molecules required for passing signals between nerve cells. cAMP active PKA neurotransmitters Ca inactive PKA

Long-Term Memory impulse cAMP levels PKA activated Existing proteins activated CREB activated New protein synthesis Learning and memory (STM) Memory Only (LTM) The initial steps are the same for long-term and short-term memories. Long-term memories require additional steps to create permanent changes in the nervous system.

Long-Term Memory CREB  gene transcription  new proteins. New proteins permanently activate the neuron and promote more neural connections. In addition to the increased levels and activation of existing proteins needed for short-term memory, CREB turns on genes for new protein production. These proteins permanently activate the neuron, and promote more neural connections. cAMP  PKA  Ca ++ and neurotransmitter release AND PKA  active CREB cAMP active PKA neurotransmitters Ca receptors new proteins CREB cAMP active PKA neurotransmitters Ca receptors active CREB PKA

Memory Mutants Mice as Food CriticsMorris Water MazeIdentity of dunce

Mice as Food Critics The food critic mouse encounters a new food. Some of the food sticks to the critic’s whiskers. The mice socialize. They smell the food on the food critic’s whiskers… The mice find several foods then choose the food that smells like the food critic’s whiskers. Ah, peanut butter… The mice REMEMBER the odor from the food critic mouse.

The food critic mouse encounters a new food. Some of the food sticks to the critic’s whiskers. The food critic mouse socialized with wild-type and CREB mutant mice. All of the mice smell the food on the food critic’s whiskers… Wild-type mice choose the food that smells like the food critic’s whiskers. CREB mutant mice choose food at random. CREB mutants CAN’T remember which odor the food critic introduced them to. What happens when the food critic tries to teach mutant mice?

Morris Water Maze Platform

Morris Water Maze, continued

More Mutant Mice? Pre-synaptic axon Post-synaptic dendrite neurotransmitters NMDA receptor synapse

More Mutant Mice?

Pre-synaptic axon Post-synaptic dendrite neurotransmitters NMDA receptor synapse Pre-synaptic axon Post-synaptic dendrite neurotransmitters NMDA receptor synapse Synapse in normal mice Synapse in NMDA mutant mice

Discover the Identity of dunce

impulse cAMP levels PKA activated Existing proteins activated CREB activated New protein synthesis Learning and memory (STM) Memory Only (LTM)

Discover the Identity of dunce impulse cAMP levels PKA activated Existing proteins activated CREB activated New protein synthesis Learning and memory (STM) Memory Only (LTM) dunce mutations affect this step.