Effects of DFP on unit activity in rat superior colliculus.

The effect of systemically administered diisopropylfluorophosphate (DFP) on the spontaneous firing rate and light-evoked responses of rat superior colliculus neurons was determined from average histograms of single unit and multiunit activity. DFP produced a dose-dependent increase in superior colliculus spontaneous activity, and a decrease in light evoked activity. In many experiments, light evoked responses were completely abolished. The changes in spontaneous activity were reversible over a period of about 5 hours following DFP injection. These results establish the retino-tectal pathway as a major target of DFP toxicity.