Sleep patterns of the laboratory cat.

The effects of feeding schedule and external stimuli on sleep patterns were investigated in cats fed to maintain their mean body weight. The ECoG, EOG and EMG wer recorded from 3 male cats fed once daily and under a 12:12 light--dark schedule. The results for 15 working days were compared with those obtained at week-ends and under continuous lighting, fasting, reduced food intake or overfeeding. Feeding was also divided into 3 meals per day. Despite some differences in their responsiveness. All cats exhibited the usual values for the critical variables of SWS: diurnal placement, intermittency and total amount. A low percentage of PS per 24 h was recorded. This was related both to the restricted amount of food eaten and to the feeding schedule. Reduced external stimuli at week-ends resulted in concentration of sleep during daytime, whereas sleep was reduced during continuous lighting in conjunction with an increased percentage of drowsinessess. The most marked effect of fasting (pig fat) was fragmentation of sleep episodes. Divided meals and an increased food intake both increased the total sleep duration. It is suggested that the restricted amount of food and relatively enriched environment used, accompanied by a reduced sleep duration, may be comparable to that seen in free animals. Sleep patterns in the cat are very responsive to light--dark schedule, reduced external stimuli and fasting.