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PRESYNAPTIC AND POSTSYNAPTIC INHIBITION


PRESYNAPTIC AND POSTSYNAPTIC INHIBITION
Inhibitory synapses modulate neuronal excitability. Presynaptic inhibition (left) and postsynaptic inhibition (right) are shown in relation to a motor neuron. 

PRESYNAPTIC AND POSTSYNAPTIC INHIBITION

Postsynaptic inhibition causes local hyperpolarization at the postsynaptic site. Presynaptic inhibition involves the depolarization of an excitatory axon terminal, which decreases the amount of Ca2+ influx that occurs with depolarization of that excitatory terminal, thus reducing the resultant EPSP at the postsynaptic site.