Effects of paradoxical sleep deprivation in the rabbit

The effects of nonpharmacologically-induced deprivation of paradoxical sleep for a 24 hour period were studied in rabbits. Response characteristics commonly associated with the deprivation procedure in other species were observed, as well as features apparently peculiar to the rabbit. Like other mammals, rabbits: (1) show increased attempts to experience PS during the deprivation procedure relative to the baseline occurrence of PS; (2) become increasingly difficult to arouse from PS as the deprivation period progresses; (3) show increased amounts of PS (rebound) in post-deprivation recordings relative to baseline; and (4) compensate for only one-third of the PS deficit incurred during deprivation. Rabbits' response to PS deprivation differs from other mammals in the following ways: (1) the deprivation procedure is truly selective, significantly affecting only amounts of PS and not total sleep time or other sleep stages; (2) the rebound response is restricted to the light phase of the light-dark cycle on the first recovery day; and (3) as indexed by eye movement density, phasic activity during PS is not enhanced during the recovery period. Given that the crucial factor in the PS deprivation-compensation phenomenon is thought to be the deprivation and subsequent enhanced occurrence of phasic events, and considering that events within the oculomotor system have been emphasized in this regard, the results of this investigation suggest the existence of species differences regarding the nature and form of the compensatory response to PS deprivation.