1. (a) g K, V m = E K (b) g Na >> g K, sodium influx (c) g K >> g Na, pottassium efflux (d) g K, V m = E K A Mechanism for the Action Potential

2. Action Potential Conduction (part I) Entry of positive charge during the action potential causes the membrane just ahead to depolarize to threshold. Because the axonal membrane is excitable the action potential travels without decrement. Typical conduction velocity: 10 m/sec Conduction velocity increases with axonal diameter

3. Stellate cell-constant firing rate Pyramidal cell-Adaptation, decreased firing rate over time OR, Bursting, rapid cluster of action potentials followed by a pause. Neurons Exhibit Different Patterns of Action Potential Generation

5. Action potentials invading the axon terminals cause the release of chemical neurotransmitters

6. Neurons can: transmit a chemical signal (known as neurotransmitters) receive signals through receptors that bind neurotransmitters

8. Can study receptor subtypes using different drugs One neurotransmitter can bind to multiple receptor types No two transmitters bind to the same receptor There can be multiple receptor subtypes

9. Cholinergic synaptic transmission Heterogeneous localization of receptors (e.g. - heart versus skeletal muscle) Agonists versus antagonists

10. Glutamatergic synaptic transmission

12. Dendrites integrate information from multiple inputs

13. The Action potential Integrated synaptic inputs determines whether a neuron reaches threshold to fire an action potential

14. Experience can modify the contribution of inputs

15. Drugs can alter synaptic communication between neurons

18. COCAINE euphoria reduced hunger feeling of strength

21. This is your brain. This is your brain...