G. Carli

Presynaptic and postsynaptic inhibition on transmission of cutaneous afferent volleys through the cuneate nucleus during sleep

Durante i movimenti rapidi oculari caratteristici della fase desincronizzata di sonno si osserva una depressione fasica della risposta lemniscale alla stimolazione di fibre cutanée. Questa modulazione ipnica della risposta lemniscale è dovuta a meccanismi di inibizione presinaptica e postsinaptica.

Transmission of somatic sensory volleys through ascending spinal hindlimb pathways during sleep and wakefulness

SummaryIn unrestrained, unanaesthetized cats the mass discharge recorded from the ventral and lateral funicles on single shock stimulation of ipsilateral hindlimb nerves was investigated during physiological sleep and wakefulness. The response elicited polysynaptically by stimulation of the cutaneous and high threshold muscular afferents was not affected during quiet wakefulness and synchronized sleep, nor during desynchronized sleep, in the absence of ocular movements. A depression of the response, however, occurred particularly during the bursts of rapid eye movements characteristic of the desynchronized sleep and also during the transient orienting reaction associated with arousal of the animal. It is suggested that the depression is due to supraspinal inhibition of the interneurons which transmit these somatic afferent volleys to ascending spinal hindlimb pathways, probably including the spinoreticular tract.