Taste avoidance caused by spontaneous wheel running: effects of duration and delay of wheel confinement

Confinement of a rat in a running wheel results in the rat's subsequent avoidance of the taste consumed before the confinement. This phenomenon has been ascribed to taste aversion conditioned by spontaneous wheel running. As a first step toward clarification of the underlying mechanism of this phenomenon, we manipulated two parameters of the taste-confinement procedure: duration of wheel confinement (Experiments 1A and 1B) and temporal intervals between the taste consumption and the wheel confinement (Experiments 2A and 2B). In general, longer confinement and shorter inter-event interval caused stronger taste avoidance. However, the results also suggested that it is possible to establish taste avoidance when wheel confinement was delayed 1-h after the taste consumption. These results correspond to those of conventional taste aversion caused by illness-inducing agents, suggesting similar mechanisms in the both preparations. Experiment 3 revealed that running in a wheel rather than wheel confinement itself is the effective factor for establishing taste avoidance.