Ferraro J S, McCormack C E
Physiol Behav. 1986;38(1):139-44. doi: 10.1016/0031-9384(86)90144-7.
To further explore the validity of the non-parametric model of entrainment for predicting the phase-shifting effects of light pulses, we exposed rats to several intensities of continuous light (LL) and feedback lighting (LDFB). LDFB is a lighting condition that exposes the animal to light only during the interval of active locomotion; this interval is coincident with the photosensitive portion of the circadian cycle as defined by the phase-response-curve. This is achieved by linking lights on with locomotor activity. In addition to the comparison of LL with LDFB, the duration of the LDFB pulse was also varied in four rats. Whether rats were exposed to LL or LDFB, as light intensity increased, the free-running period (tau) of the locomotor activity rhythm also increased. This intensity-related increase in tau, which is known as the Aschoff effect, was similar for LL and LDFB 2 min at each light intensity (0.1, 1, and 100 lux). However, when the LDFB pulses were shortened from a duration of 2 min to a duration of approximately 1 sec, tau shortened significantly. These results demonstrate that the non-parametric model of entrainment adequately explains the major period-lengthening effects of LL. However, there are temporal limits to the light pulses that can be used to simulate the effects of LL (i.e., one second light pulses fail to produce the effects brought about by longer pulses).
为了进一步探究用于预测光脉冲相移效应的非参数夹带模型的有效性，我们将大鼠暴露于几种强度的持续光照（LL）和反馈光照（LDFB）下。LDFB是一种光照条件，仅在主动运动期间将动物暴露于光照下；该时间段与由相位响应曲线定义的昼夜节律周期的光敏部分一致。这是通过将光照与运动活动联系起来实现的。除了比较LL和LDFB外，还对4只大鼠改变了LDFB脉冲的持续时间。无论大鼠是暴露于LL还是LDFB，随着光照强度增加，运动活动节律的自由运行周期（tau）也增加。这种与强度相关的tau增加，即所谓的阿绍夫效应，在每种光照强度（0.1、1和100勒克斯）下，LL和LDFB持续2分钟时是相似的。然而，当LDFB脉冲从2分钟的持续时间缩短至约1秒的持续时间时，tau显著缩短。这些结果表明，非参数夹带模型充分解释了LL的主要周期延长效应。然而，用于模拟LL效应的光脉冲存在时间限制（即一秒钟的光脉冲无法产生较长脉冲所带来的效应）。
