Effects of postsynaptic depolarization in the induction of synaptic depression between a granule cell and a Purkinje cell in rat cerebellar culture

In a previous paper it has been reported that the repetitive conjunctive stimulation of both a granule cell and an inferior-olivary neuron depresses the synaptic transmission between a cerebellar granule cell and a Purkinje cell, and the repetitive stimulation of only a granule cell potentiates the transmission in a simple culture preparation. This paper demonstrates, by experiments controlling the membrane potential of a postsynaptic Purkinje cell, that the postsynaptic depolarization of a Purkinje cell during activation of a granule cell is both necessary and sufficient to induce the depression, and that the potentiation is induced without the postsynaptic depolarization.