Effects of ethanol on visual evoked responses in monkeys performing a memory task

The effects of ethanol on behavior and visual evoked potentials were investigated in monkeys performing a visual short-term memory task. Ethanol induced a dose-dependent deficit in performance and a prolongation of visuo-motor reaction time. The normal patterns of ocular motility were concomitantly altered. The potentials elicited in the lateral geniculate nucleus, the striate cortex, the inferotemporal cortex, the amygdala, and the mesencephalic reticular formation by a colored stimulus used by the animal in the task were attenuated by the alcohol in dose-related manner. In contrast, potentials elicited in the striate cortex and reticular formation by a brief and diffuse flash were augmented under the influence of the substance. It is inferred that ethanol can increase the reactivity of reticular and cortical structures to undifferentiated stimuli, while at the same time interfering with the basic mechanisms of visual attention and perception.