[Firing patterns of the pontine omnipause neurons during sleep in the cat]

The omnipause neurons (OPNs), located in the nuculeus raphe pontis, cease firing during all rapid eye movements and otherwise fire at a steady rate in the awake state. Firing patterns of the OPNs were studied during the awake state, non-REM sleep, and REM sleep in chronically prepared adult cats, to examine whether the OPNs' firing participates in the genesis of eye movements during each state. During non-REM sleep, the OPNs continued their firing, and their firing patterns had little correlation with slow drifting eye movements appearing in this state. During REM sleep, the OPNs maintained a tonic firing and ceased their firing during rapid eye movements in all directions. These results suggest that cessation of OPN firing plays an important role in the generation of rapid eye movements during REM sleep as well as during the awake state in the cat.