Effects of alcohol on successive incentive contrast

Abstract

The effects of alcohol on successive positive-and negative-incentive contrast effects resulting from shifts in magnitude of food reward were studied in a runway conditioning experiment with female albino rats. Immediately prior to the conditioning trials, half of the fluid-deprived animals consumed a 10% sucrose solution, and half consumed a 10 % sucrose solution containing 4.8 % ethanol. A negative-incentive contrast effect occurred under both fluid conditions, but a positiveincentive contrast effect did not occur under either fluid condition. Thus, there was no evidence that alcohol either eliminated negative emotional reactions to downshifts in reward or contributed to positive emotional reactions to upshifts in reward. On the contrary, consuming alcohol had negative consequences on runway performance, causing the successive negative contrast effect to be more protracted than it was among the animals that did not consume alcohol. The results suggest that consuming alcohol following incentive reduction interferes with animals' disengagement from the lost incentive.

A motivational model of alcohol use.

“…In one experiment (Cox, 1981), the inebriated rats (unlike the sober rats) showed a pronounced positive contrast effect. In another experiment (Cox, 1988), the negative contrast effect differed among inebriated and sober rats in that the inebriated rats initially showed less abrupt reductions in running speeds than the sober ones, but the inebriated animals were slower to recover from the reduction in reward. The latter result suggests that coping with an incentive loss by drinking alcohol might be maladaptive.…”

“…To explore these possibilities, Cox and colleagues (Cox, 1981(Cox, , 1988Cox, Klinger, & Kemble, 1987) compared reactions to incentive shifts of rats that had consumed an alcoholic solution prior to their conditioning trials with those that had consumed a nonalcoholic solution. Results obtained with the sober rats were consistent with those of the many incentive contrast studies that have followed those of Crespi (1942) and Zeaman (1949).…”

“…That is, alcohol, through its attenuation of the negative emotional reaction to a downshift in reward, might reduce or eliminate the negative incentive contrast effect. Through its enhancement of a positive emotional reaction to an upshift in reward, alcohol might contribute to a positive incentive contrast effect.To explore these possibilities, Cox and colleagues (Cox, 1981(Cox, , 1988Cox, Klinger, & Kemble, 1987) compared reactions to incentive shifts of rats that had consumed an alcoholic solution prior to their conditioning trials with those that had consumed a nonalcoholic solution. Results obtained with the sober rats were consistent with those of the many incentive contrast studies that have followed those of Crespi (1942) and Zeaman (1949).…”

Emotional reactivity to incentive downshift as a correlated response to selection of high and low alcohol preferring mice and an influencing factor on ethanol intake

“…Early preclinical consummatory incentive downshift data suggest that ethanol administration during recovery from contrast, after the initial reaction on post-shift day 1, attenuates contrast (Becker and Flaherty 1982, Becker and Flaherty 1983). Two additional instrumental contrast studies by Cox and colleagues (1987, 1988) suggest that ethanol reduces contrast during all post-shift days. Cox et al (1988) showed that alcohol consumption prior to incentive downshift also prolonged recovery from incentive downshift.…”

“…Two additional instrumental contrast studies by Cox and colleagues (1987, 1988) suggest that ethanol reduces contrast during all post-shift days. Cox et al (1988) showed that alcohol consumption prior to incentive downshift also prolonged recovery from incentive downshift. It is possible the different results were due to use of different downshift procedures (Flaherty 1996).…”