Increases in paradoxical sleep as a result of amygdaloid stimulation

Holtzman rats were partially and selectively deprived of paradoxical sleep (PS) for a 16 1/2 hr period and allowed to rest for a 7 1/2 hr period each day. Test animals were given mild (60 Hz, 50 muA) unilateral amygdaloid stimulation for one min each day of a 5 day test period. There was a significant increase in PS during the rest periods of test animals on stimulation days when compared to nonstimulated controls. The effect did not last beyond a 5 day period. Only subconvulsive behaviour was observed in two test animals. The similarity to the PS increases in this study to those seen in conventional learning and other stiuations are discussed.