LONG-TERM SLEEP-DEPRIVATION BY HYPOTHALAMIC-STIMULATION IN CATS

Several techniques were developed to prevent sleep in animals in order to examine the biological role fulfilled by sleep; however, most were either stressful or difficult to accomplish routinely, especially in such a large animal as the cat. Electrical stimulation of activating structures in the brain presents a very attractive alternative to peripheral stimulation used by the usual sleep deprivation methods although it has been rarely tried. The paper describes a microcomputer-based system used to achieve sleep deprivation in cats by stimulating the hypothalamic predatory area with short trains. During control days and deprivation the electrocorticogram (EEG), electromiogram (EMG) and electrooculogram (EOG) were continuosly digitalized by the computer in 5 s epochs and the integrated power of the 4 usual frequency bands of the EEG (alpha, beta, delta, theta) as well as the variance of EMG and EOG signals were calculated. Criteria for stimulus delivery were based on the integrated power of the delta band and on the variance of EMG but the flexibility of the computer ensures that any other parameter can be used to achieve total or selective sleep deprivation.