Ethanol's effect on selective gating of somatic sensory inputs to single cortical neurons.

The effect of alcohol intoxication was tested on sensory responses of single units in the somatosensory (SI) cortex of awake, freely moving rats. We have previously shown that transmission of cutaneous sensory information from the paw to the cortex during movement is subject to a time varying pattern of sensory suppression which selectively "gates in" sensory information to particular categories of cortical neurons during certain phases of the locomotor step cycle. In the period of 5-20 minutes after alcohol administration (when the rats became hyperactive) the afferent inhibition producing this selective gating was reduced or abolished, depending on the ethanol dose (between 0.75 and 1.5 g/kg). This indicates that the selective suppression of "irrelevant" inputs to certain cortical cells, which is normally seen during movement, is absent during alcohol intoxication. This paradigm may provide a model for study of the neurophysiologic mechanism by which alcohol disturbs higher cognitive functions involving cortical management of sensorimotor tasks.