Light and dark pulse response curves in a day active palm squirrel Funambulus palmarum.

Light pulses (L-pulses 1 h, 1000 1x) and dark pulses (D-pulses, 2 h) reset the phases of the circadian rhythm of locomotor activity in the day active palm squirrel Funambulus palmarum. The phase response curves (PRCs) constructed from steady-state phase shifts (delta phi s) thus caused conformation to the generalization that the time course and wave form of the light pulse PRC (LP-PRC) and dark pulse PRC (DP-PRC) should be opposite in sign. No consistent correlations could be detected in the wake of L- and D-perturbations between the direction of transients, changes in the period length (tau) and the direction of steady state delta phi s.