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