[Effects of fimbria-fornix lesion on the temporal discrimination revealed by peak interval procedure in rats].

When temporal discrimination is examined by a peak interval (PI) procedure in rats, a shortening of peak time is induced by the fimbria-fornix (FF) lesion. The aim of this research is to investigate the extent of peak time shortening induced by FF lesion and the acquisition process of temporal discrimination. In FF lesioned rats, the peak time was very short (about 13 sec) in earlier phase, then became longer as the training progressed and reached a steady level, which was approximately 20% shorter than control rats. These results suggest that the "non-timing process" is involved in addition to the "timing process" in FF lesioned rats.