UW Gives Rats Jell-O Shots

University of Washington scientists gave rats Jell-O shots to study links between adolescent alcohol abuse and adult decision-making, the UW reported in a news release.

Some of the alcohol-consuming rats were then given a choice of pushing a lever that always gave them two sugary pellets or another lever that gave them a larger but uncertain reward of either four or zero treats, according to a UW news release.

The "party rats" more often chose uncertain rewards while a control group of teetotaling rats matched their choice well to whichever lever had the probability giving the larger reward, the UW said.

"This model using rats lends support to causal link between early alcohol use and later increased risky decision making," said Nicholas Nasrallah, a UW psychology doctoral student and co-author of the study.

Rats usually don't drink alcohol, but researchers found that they consume ethanol when it is combined with gelatin.

One group of rats was given 24-hour access to a 10 percent solution of ethanol in a tasty gel. The rats were 30 to 49 days old during the experiment, corresponding to human adolescence. The rats consumed the alcohol-laced gel each day in amounts equivalent to a large number of drinks in human terms, said corresponding author Ilene Bernstein, a UW professor of psychology and faculty member of the program in neurobiology and behavior.

A separate control group of rats was given a gel made without any alcohol. At the end of the 20 days, the gelatin was withdrawn from both groups.

Three weeks later, half of the rats from each group were trained to press levers to receive the treats. Part of the training included a "forced choice" where there was only one lever to press. This gave the rats an opportunity to sample the pay-off schedule on the uncertain lever that day. Three days of trials were run with the payoff for the large but uncertain reward coming 75 percent of the time and then dropping to 50 percent and 25 percent on subsequent days.

The alcohol-exposed rats showed a strong bias toward the uncertain lever, even when the chance of receiving rewards on the third day diminished to only one in four. The control rats, however, behaved differently and adjusted perfectly to the changing conditions of the experiment, thus gaining more treats than the alcohol-exposed rats.

See more about the study at uwnews.org.