Figure 7.

Schematic representation of the dissociation and slow resynchronization of endogenous oscillators within the rat SCN after an LD cycle shift. The light-responsive and -unresponsive clocks in the SCN are dissociated by light exposure in the subjective night. The phase of the light-responsive clock in the ventrolateral region of the SCN shifts rapidly, but the phase of the light-unresponsive one in the dorsomedial region is relatively slow to shift. During the period of desynchrony, the animals display increased nighttime rest. OC, Optic chiasm; III, the third ventricle.