Effects of ethanol on working memory and attention in pigeons

To determine whether the effects of ethanol on working memory are mediated by a secondary effect on attention, dose-response curves for ethanol were d etermined in eight pigeons trained under a titrating matching-to-sample (TM TS) procedure, in eight pigeons trained under a discrete-trial measure of a ttention, and in eight pigeons trained under a continuous-trial measure of attention. Ethanol decreased accuracy under the TMTS procedure following th e three highest doses (1, 1.8, and 3 g/kg). Only the highest dose (3 mg/kg) decreased rates of responding. Attention, as measured under the discrete-t rial procedure, was affected only by the two highest doses (1.8 and 3 g/kg) . The 3-g/kg dose caused significant decreases in the probability of a hit and probability of a correct rejection, as well as significant increases in the probability of an error of omission and response latencies. Sensitivit y to the signal decreased following 1.8 and 3 g/kg ethanol. Under the conti nuous-trial procedure, ethanol caused a peak in false alarms after the 1.8- g/kg dose, decreased the probability of a hit following the 1.8- and 3-g/kg doses, and increased probability of a miss at all doses. Sensitivity to th e signal was not affected. A comparison of the dose-response curves for the TMTS procedure and the two measures of attention revealed that working mem ory (TMTS) was decreased by a lower dose than that affecting attention. Thi s suggests that the effects of ethanol on working memory are not mediated b y the subject's ability to pay attention to stimulus changes in the environ ment.