The effect of sleep upon the transmission of afferent activity in the somatic afferent system.
Macaque monkeys were trained to fall asleep while sitting in a primate chair with their heads restrained. A gentle vibratory stimulus was delivered to the glabrous skin of the hand; it did not provoke awakening or change the sleep cycle of the macaque.  Postcentral neuronal response to the amplitude of a sine wave mechanical stimulus and neuronal spontaneous activity were observed repetitively during all the phases of normal night sleep cycles. One hundred six neurons which could be entrained by  a cutaneous mechanical stimulus were studied during both waking and sleep. At threshold, cyclic entrainment of the discharges of postcentral neurons decreased to 81 +/- 0.25% during light sleep (S1 + S2), to 64 +/- 0.26% during deep sleep (S3 + S4), and to 9 +/- 0.98% during desynchronized sleep with rapid eye movements (REMs).
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D003344:Cortical Synchronization; D005071:Evoked Potentials; D006225:Hand / Q000294:innervation; D000882:Haplorhini; D008253:Macaca mulatta; D009474:Neurons / Q000502:physiology; D012867:Skin / Q000294:innervation*; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D009435:Synaptic Transmission; D014732:Vibration; D014851:Wakefulness / Q000502:physiology