Overnight Decrement in Maze Performance of Mice Running for Food Reward

Mice were run in a T-maze for food reward, to investigate possible effects of deprivation level on “overnight decrement,” i.e., worse performance on the first trial of a given day than on the last trial of either the previous or the same day. Following an initial training period, each mouse received a series of massed trials on 22 consecutive days. On half of these days, the mice were deprived of food in their home cages; on the other half, they were not deprived. Overnight decrement was substantial only when the mice were not deprived. These results have important implications concerning the comparability of positively reinforcing brain stimulation and more conventional rewards.