Teicher M H, Flaum L E
Dev Psychobiol. 1979 Sep;12(5):441-54. doi: 10.1002/dev.420120504.
The activity of isolated rats from 6 to 25 days of age was analyzed at 10-min intervals. Ultradian peak activity rhythms, with a rough 1-2-hr periodicity, developed between 9 and 12 days of age, and reached an extreme at 15 days. Ultradian periods of attenuated activity were however detectable even in 6-day-olds. Isolated rats at 15 days of age displayed greatly accentuated profiles characterized not only by heightened activity levels, but by an extreme cyclicity. These subjects spent most of their time oscillating between periods of marked activity and marked inactivity. Both the average and total duration of these extreme periods were greater in 15-day-olds than any of the other ages. Free-running nocturnal activity rhythms were also observed to develop in isolated rats tested in continuous darkness by the 15th day.
对6至25日龄的隔离大鼠的活动情况进行了每隔10分钟一次的分析。在9至12日龄时出现了大致以1至2小时为周期的超日峰活动节律，并在15日龄时达到极值。然而，即使在6日龄的大鼠中也能检测到活动减弱的超日周期。15日龄的隔离大鼠表现出大大增强的活动模式，其特征不仅在于活动水平的提高，还在于极端的周期性。这些大鼠大部分时间在明显活动期和明显不活动期之间振荡。15日龄大鼠这些极端活动期的平均时长和总时长均比其他任何年龄的大鼠更长。到第15天时，在持续黑暗中测试的隔离大鼠也观察到了自由运行的夜间活动节律。
