Changes in circadian sleep and waking patterns after somatosensory deafferentation in the cat

The present study describes changes in circadian state pattern organization associated with somatosensory deafferentation in the adult cat. Nine animals, implanted for chronic monitoring of standard sleep state variables, were divided into 3 groups for study. Six cats received dorsal column transections at either a high (C1-C3, N = 3) or low (C5-T1, N = 3) cervical level. The remaining three served as intact controls. State evaluations of continuous 24 h polygraphic recordings disclosed a significant facilitation of alert waking and a suppression of slow wave sleep in animals with high cervical lesions; REM sleep was not affected. State pattern percentages for animals with low cervical lesions were comparable to those of intact controls; however, lesioned animals of both experimental groups showed changes in the frequency of occurrence and duration of individual sleep/wake episodes. These findings were interpreted in terms of the enhancement of intrinsic rhythmic discharge patterns over ventrobasal thalamocortical pathways.