Inhibitory input to pause neurons from pontine burst neuron area in the cat.

Extra- and intracellular recordings were made from pontine pause neurons (PNs) in the cat. Spontaneous spikes of PNs were suppressed after single shock stimulation of excitatory burst neuron (EBN) area immediately rostral to the abducens nucleus. The most effective stimulation site for the suppression was the region where long-lead burst neurons (LLBNs) were predominantly located. Intracellular recordings from PNs showed that stimulation of the LLBN area induced short-latency inhibitory postsynaptic potentials (IPSPs) in PNs and that steep hyperpolarization of PNs associated with quick phases of nystagmus occurred prior to an abrupt change in abducens nerve activity. Results suggest that a pause of PN spikes associated with quick phases is, at least in part, produced by inhibitory action mediated through LLBNs.