Anatomy of a Nerve Cell

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

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

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

4. Making A Memory

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

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

7. Ca Ca Ca Ca Ca inactive PKA cAMP cAMP Ca Ca active PKA Ca Ca neurotransmitters More Short-Term Memory Ca++ ions  cyclic AMP cAMP activates proteins required for passing signals between nerve cells cAMP  PKA  neurotransmitter release AND PKA  Ca++ prolonged neuron activity 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.

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

9. active CREB PKA cAMP active PKA Ca Ca neurotransmitters receptors CREB new proteins cAMP active PKA Ca Ca neurotransmitters receptors Long-Term Memory cAMP  PKA  Ca++ and neurotransmitter release AND PKA  active CREB 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.

10. Memory Mutants Mice as Food Critics Morris Water Maze Identity of dunce

11. Mice as Food Critics Ah, peanut butter… 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. The mice REMEMBER the odor from the food critic mouse.

12. What happens when the food critic tries to teach mutant mice? 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.

13. 1 Platform 2 4 3 Morris Water Maze

14. Morris Water Maze, continued

15. Morris Water Maze, continued

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

17. More Mutant Mice?

18. Pre-synaptic axon Pre-synaptic axon neurotransmitters neurotransmitters synapse synapse NMDA receptor NMDA receptor Post-synaptic dendrite Post-synaptic dendrite More Mutant Mice? Synapse in normal mice Synapse in NMDA mutant mice

19. Discover the Identity of dunce

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

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