Sleep disruption by nociceptive stimuli follows the apparition of a ‘cognitive’ wave, supposed to reflect the activation of a widespread cortical network (Bastuji et al Pain 2008). The aim of the present study was to characterize the post stimulus cortical network leading to sleep disruption. For this purpose, intra-cerebral electrophysiological signals during sleep were analysed in the second after delivery of nociceptive stimuli. 

Data were obtained in 17 epileptic patients receiving thermo-nociceptive stimulations, slightly above the individual pain threshold, during whole night sleep. Evoked cerebral responses within the first second after the stimulus were analysed in sensori-motor areas (post. insula, S2, mid cingulate, SMA) and multi- or supramodal associative areas (dorso-lateral prefrontal, posterior parietal, orbitofrontal, precuneus, posterior and perigenual anterior cingulate cortices). The responses  were analysed and compared according to presence or absence of arousal post-stimulus, during sleep stage N2 and paradoxical sleep (PS). 

Immediately before an arousal, the area under the curve of the evoked response was significantly enhanced,  as compared to non arousing instances, in all sensori-motor and multimodal associative areas during N2, but only in multimodal associative areas during PS. 

Between the stimulus and the arousal reaction, there were signs of increased neuronal activity, which was global in N2 stage, and which in PS concerned only multimodal associative areas, probably due to the fact that sensori-motor areas were already pre-activated during this sleep stage. This activation of sensory and association areas may facilitate information propagation leading to conscious perception and physiological response.

CEREBRAL PROCESSING OF NOCICEPTIVE STIMULI PREDICTS SLEEP DISRUPTION