Loss of slow-wave sleep (SWS) and abnormal REM sleep behaviour were associated with a lack of vegetative and endocrine circadian rhythms in a patient with fatal familial thalamic degeneration. Physiological EEG patterns of SWS (spindles, K complexes, delta activity) were absent. EEG fast rhythms could not be induced by barbiturate or benzodiazepine administration. RO 15-1788, a benzodiazepine antagonist, induced arousal and awakened the patient from coma. Pathological findings were severe neuronal loss restricted to the anterior and dorso-medial thalamic nuclei. The clinical and electrophysiological data, together with the pathological correlates, emphasize the role played by the thalamus in the regulation of the sleep-waking and other circadian cycles.
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