Acute effects of alcohol on photic evoked potentials of albino rats: visual cortex and superior colliculus.

Photic evoked potentials were recorded from the primary visual cortex (VC) and superior colliculus (SC) of chronically implanted rats. Animals were given intraperitoneal injections of saline, 1.5 and 2.5 g ethyl alcohol/kg body weight on separate days. Evoked potentials were recorded at 5, 20, 40 and 60 min following injection. The amplitudes of all of the VC components except P2 (latency of 52 msec) were depressed to some extent by both doses of alcohol. In contrast, the amplitude of component P2 was increased by both alcohol doses. In the SC, the peak amplitudes of two individual components of the early positive complex were diminished by both doses of alcohol, as was a later negative component. A series of late oscillatory potentials recorded from the SC were minimally depressed by the 1.5 g/kg dose of alcohol, but showed a more prolonged depressant effect at the higher dose. Both doses of alcohol produced reliable increases in peak latency for the primary components in the VC and SC.