1. Chapter 8c Neurons: Cellular and Network Properties

2. Integration: Divergence Figure 8-25a

3. Integration: Convergence Figure 8-25b

4. Integration: The Abundance of Synapses on a Postsynaptic Neuron Figure 8-26 Axon terminals of presynaptic neurons Axon Glial cell processes Dendrite of postsynaptic neuron

5. Integration: Purkinje cell The highly branched dendrites of a Purkinje cell (neuron) demonstrate convergence Figure 8-27

6. Integration: Spatial Summation Figure 8-28a, step 1 1 Three excitatory neurons fire. Their graded potentials separately are all below threshold. Trigger zone Presynaptic axon terminal Action potential (a) 1

7. Integration: Spatial Summation Figure 8-28a, step 2 1 Three excitatory neurons fire. Their graded potentials separately are all below threshold. Graded potentials arrive at trigger zone together and sum to create a suprathreshold signal. Trigger zone Presynaptic axon terminal Action potential (a) 1 2 2

8. Integration: Spatial Summation Figure 8-28a, step 3 1 Three excitatory neurons fire. Their graded potentials separately are all below threshold. An action potential is generated. Graded potentials arrive at trigger zone together and sum to create a suprathreshold signal. Trigger zone Presynaptic axon terminal Action potential (a) 1 2 2 3 3

9. Integration: Spatial Summation Figure 8-28a 1 Three excitatory neurons fire. Their graded potentials separately are all below threshold. An action potential is generated. Graded potentials arrive at trigger zone together and sum to create a suprathreshold signal. Trigger zone Presynaptic axon terminal Action potential (a) 1 2 2 3 3

10. Integration: Spatial Summation Figure 8-28b, step 1 1 One inhibitory and two excitatory neurons fire. Inhibitory neuron Trigger zone (b) No action potential 1

11. Integration: Spatial Summation Figure 8-28b, step 2 1 The summed potentials are below threshold, so no action potential is generated. One inhibitory and two excitatory neurons fire. Inhibitory neuron Trigger zone (b) No action potential 1 2 2

12. Integration: Spatial Summation Figure 8-28b 1 The summed potentials are below threshold, so no action potential is generated. One inhibitory and two excitatory neurons fire. Inhibitory neuron Trigger zone (b) No action potential 1 2 2

13. Integration: Temporal Summation Figure 8-29a

14. Integration: Temporal Summation Figure 8-29b

15. Integration: Presynaptic Inhibition Figure 8-31a 321321 An action potential is generated. An excitatory neuron fires. An inhibitory neuron fires, blocking neurotransmitter release at one synapse. (a) Presynaptic inhibition Presynaptic axon terminal Action potential Target cell No neurotransmitter release No response Neurotransmitter released Inhibitory neuron Excitatory neuron Response

16. Integration: Postsynaptic Inhibition Figure 8-31b 123 4 Modulated signal in postsynaptic neuron below threshold. One excitatory and one inhibitory presynaptic neuron fire. No action potential initiated at trigger zone. No response in any target cell. Inhibitory neuron modulates the signal. Excitatory neuron (b) Postsynaptic inhibition No response IPSP + EPSP PLAY Interactive Physiology ® Animation: Nervous II: Synaptic Potentials and Cellular Integration

17. Figure 8-33 Integration: Growth Cones of a Developing Axon Survival of neurons depend on neurotrophic factors

18. Integration: Injury to Neurons Figure 8-34 AxonMyelin Proximal stump Distal stump Site of injury

19. Summary Organization of the nervous system CNS – brain and spinal cord PNS – peripheral nerves and ganglia, sensory receptors Afferent – sensory Efferent motor Somatic Autonomic Sympathetic Parasympathetic

20. Summary Cells of the nervous system Cell body, dendrites, axon, and axon terminal Interneurons, synapse, postsynaptic cell, presynaptic cell, synaptic cleft, and axonal transport Glial cells, Schwann cells, satellite cells, microglial, oligodendrocytes, astrocytes, and ependymal cells Myelin sheaths, nodes of Ranvier, and neural stem cells

21. Summary Electrical signals in neurons GHK equation, graded potentials, local current flow, action potentials, trigger zone, threshold, and all-or-none depolarizations Activation gate, inactivation gate, absolute refractory period, relative refractory period, and conduction

22. Summary Cell-to-cell communication Electrical synapses, chemical synapses, and synaptic vesicles Cholinergic neurons, adrenergic neurons, acetylcholine, norepinephrine, glutamate, GABA, serotonin, adenosine, and nitric oxide Fast synaptic potentials and slow synaptic potentials Integration of neural information transfer Divergence, convergence, spatial summation, temporal summation, presynaptic modulation, postsynaptic modulation, and long-term potentiation