Event-related potentials in the frontal cortex, hippocampus, and cerebellum during a temporal discrimination task in rats.

The purpose of this study was to evaluate the roles of the frontal cortex, hippocampus, and cerebellum in timing and time perception using event-related potentials (ERPs) in rats. Rats were trained to discriminate between 2-s and 8-s auditory signal durations using a choice procedure. A simple reaction-time task using only the 2-s signal served as the control condition. In both tasks, ERPs were computed at stimulus onset and offset. Auditory ERPs were recorded from the frontal cortex, hippocampus, and cerebellum. The stimulus onset ERPs consisted of P2, N2, and P3-like components. Significantly greater amplitudes of the P3-like components were observed during the temporal-discrimination task when compared to the simple reaction-time task. At the stimulus offset, P2, N2, and P3-like components were elicited as well as the stimulus onset. Only in the frontal cortex was the P3-like component that appeared at the stimulus offset larger for the temporal-discrimination task than for the simple reaction-time task. These results suggest that the frontal cortex, hippocampus, and cerebellum contribute to interval timing in the seconds range.