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Postsynaptic Potentials

Postsynaptic Potentials - at the trigger zone then the...

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Postsynaptic Potentials The release of NT from the presynaptic cell causes a response in the postsynaptic cell via the action of receptors. If the response makes the cell more likely to fire an AP, the the response is called an excitatory postsynaptic potential . EPSPs are often the result of Na + flowing into the cell through ion channels causing a depolarization. In contrast, if the response makes the postsynaptic cell less likely to fire an AP, it is called an inhibitory postsynaptic potential . An IPSP is usually result of Cl - flowing into the cell or K + leaving the cell through ion channels. Neuronal Processing Post-synaptic potentials occur at the dendrites of the receiving cells. But action potentials are only initiated at the trigger zone of the axon. Therefore, if the total electrical activity of the cell results in a depolarization past threshold
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Unformatted text preview: at the trigger zone, then the neuron will fire an action potential. The net summation of postsynaptic potentials in the trigger zone determines whether a neuron will fire an AP. Two types of summation are important in neuronal signaling. Temporal summation occurs when a single synapse receives many inputs in a short period of time (high frequency). In contrast, spatial summation occurs when a single cell receives signals from many presynaptic cells. Often information in the nervous system need to be integrated and processed by one or a group of neurons. This is the principle of convergence . Several inputs into one cell will determine if that cell fires an AP and passes along the information. Similarly, a single cell can release NTs onto several different cells and cause a divergence in the information pathway....
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