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Published byJonathon Vidal Modified over 2 years ago

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Neural Signaling: Postsynaptic Potentials Lesson 9

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Neural Signaling: Within neuron n Electrical signal n Dendrites & soma l postsynaptic potentials (PSP) l passive current n Axon l action potentials (AP) l propagated / regenerated ~

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Postsynaptic Potentials Presynaptic neuron Postsynaptic neuron Synapse

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Postsynaptic Potentials - PSPs n Changes in E m n Chemically-gated ion channels l neurotransmitters n PSP characteristics l Graded l Summation l Fast l Decremental ~

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Post-synaptic Potentials n Generation of PSP l NT binds to receptor l specific ion channels open l ion moves according to gradients n Neural signal l Na + influx excitation ( AP) l K + efflux inhibition ( AP) ~

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n Excitatory Postsynaptic Potential n Na+ influx n Depolarization (+) l E m becomes more positive l APs more likely ~ EPSPs

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0 mV - 70 mVAT REST EmEm Time EPSP + - Record here +

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n Inhibitory Postsynaptic Potential n K + efflux n hyperpolarization (-) l E m becomes more negative l APs less likely n similar to EPSPs l EXCEPT opposite ~ IPSPs

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- 70 mVAT REST EmEm Time IPSP + - -

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Integration: Summation n Temporal summation l repeated stimulation at same synapse(s) n Spatial summation l stimulation from multiple synapses n EPSPs & IPSPs summate l a maximum for both ~

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Temporal Summation n Repeated stimulation n same synapse ~ + AT REST Time mV - 70 mV EmEm

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Temporal Summation more depolarization + AT REST Time mV - 70 mV EmEm

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Spatial Summation + n Multiple synapses + AT REST Time mV - 70 mV EmEm

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EPSPs & IPSPs summate n Net stimulation l EPSPs + IPSPs = net effects n Integration l net effects = decision l excitation l inhibition n or action potentials ~

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- 70 mV EPSP IPSP +

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Postsynaptic Potentials n EPSP l Excitatory l Depolarization l Na+ influx l AP more likely n IPSP l Inhibitory l Hyperpolarization l K+ efflux l AP less likely n Soma & Dendrites n Chemically-gated channels n Passive current n Graded n Summation

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