Effects of ethanol on nonspatial working memory and attention in rats.

Investigation into the neural basis for ethanol-induced cognitive dysfunction requires the use of valid animal models. An operant signal detection procedure was developed to assess simultaneously the processes of sustained attention and working memory in rats, and to determine the effects of ethanol on these cognitive functions. Ethanol, at 0.75 g/kg ip, produced delay- and stimulus length-dependent decreases in choice accuracy, effects that are consistent with deficits in both working memory and sustained attention. Local infusion of ethanol directly into the medial septal area resulted in a selective loss of choice accuracy at the long delay. The impairment by intraseptal ethanol did not interact with stimulus length. Thus, the working memory impairment, but not the decrement in sustained attention, was mimicked by intraseptal ethanol. The current model provides a foundation for studying the neural basis of ethanol's cognitive effects.