Phase shifting circadian rhythms produces retrograde amnesia.

Phase shifting circadian rhythms in rats shortly after passive avoidance training impaired their performance on retention tests. The amnesia was not due to simple performance deficits accompanying the "jet leg" effects of phase shifting or to differences in lighting or circadian phase at training and at testing. Amnesia was associated with specific rhythm reentrainment patterns. These data indicate that disrupting circadian organization can produce retrograde amnesia in rats.