Restricted daily feeding does not entrain circadian rhythms of the suprachiasmatic nucleus in the rat.

Neural activity of the suprachiasmatic nucleus (SCN) in male albino rats was recorded under restricted daily feeding schedule. Circadian rhythm in multiple unit activity from the SCN showed essentially no interference with daily food cyclicity, while significant re-distribution of motor activities occurred during such a schedule. Since the central pacemaker is presumed to be unaffected by food availability, these results provide more support to the widespread notion that the SCN is an anatomical locus of the circadian pacemaker in rodents.