INHIBITORY INPUT TO PAUSE NEURONS FROM PONTINE BURST NEURON AREA IN THE CAT

Extra- and intracellular recordings were made from pontine pause neuro ns (PNs) in the cat. Spontaneous spikes of PNs were suppressed after s ingle shock stimulation of excitatory burst neuron (EBN) area immediat ely rostral to the abducens nucleus. The most effective stimulation si te for the suppression was the region where long-lead burst neurons (L LBNs) were predominantly located. Intracellular recordings from PNs sh owed that stimulation of the LLBN area induced short-latency inhibitor y postsynaptic potentials (IPSPs) in PNs and that steep hyperpolarizat ion of PNs associated with quick phases of nystagmus occurred prior to an abrupt change in abducens nerve activity. Results suggest that a p ause of PN spikes associated with quick phases is, at least in part, p roduced by inhibitory action mediated through LLBNs.