Synaptic plasticity: The effect of the action potential in the postsynaptic neuron

Abstract

Experiments were designed to test the hypothesis that the occurrence of an action potential in the postsynaptic neuron has a facilitating effect on the EPSP with which it is paired. The hypothesis was tested using intracellular recording in cells of the abdominal ganglion of Aplysia californica. In one series of experiments, a spontaneous EPSP was identified by an on-line LINC computer and was followed immediately by an induced action potential. The association of the EPSP with the action potential was measured in control periods preceding and following the periods of pairing. The spontaneous association of the EPSP with the action potential did not increase related to this pairing. In a second series of experiments, an EPSP evoked by nerve stimulation was preceded or followed by an induced action potential, and the change in amplitude of the EPSP was measured. No change in EPSP amplitude occurred. These findings do not support the hypothesis tested.