Sleep deprivation affects somatosensory cortex excitability as tested through median nerve stimulation

Maurizio Gorgoni; Fabio Ferlazzo; Fabio Moroni; Aurora D'Atri; Stefania Donarelli; Stefania Fanelli; Isabella Gizzi Torriglia; Giulia Lauri; Michele Ferrara; Cristina Marzano; Paolo Maria Rossini; Placido Bramanti; Luigi De Gennaro

doi:10.1016/j.brs.2014.04.006

Sleep deprivation affects somatosensory cortex excitability as tested through median nerve stimulation

Brain Stimul. 2014 Sep-Oct;7(5):732-9. doi: 10.1016/j.brs.2014.04.006. Epub 2014 May 23.

Affiliations

¹ Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
² Department of Psychology, University of Bologna, Bologna, Italy.
³ Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
⁴ Institute of Neurology, Catholic University of The Sacred Heart, Rome, Italy; IRCCS San Raffaele Pisana, Rome, Italy.
⁵ IRCCS Bonino-Pulejo, Messina, Italy.
⁶ Department of Psychology, "Sapienza" University of Rome, Rome, Italy; IRCCS San Raffaele Pisana, Rome, Italy. Electronic address: luigi.degennaro@uniroma1.it.

PMID: 24953258
DOI: 10.1016/j.brs.2014.04.006

Abstract

Background: Changes of cortical excitability after sleep deprivation (SD) in humans have been investigated mostly in motor cortex, while there is little empirical evidence concerning somatosensory cortex, and its plastic changes across SD.

Objective: To assess excitability of primary somatosensory cortex (S1) and EEG voltage topographical characteristics associated with somatosensory evoked potentials (SEPs) during SD.

Methods: Across 41 h of SD, 16 healthy subjects participated in 4 experimental sessions (11.00 a.m. and 11.00 p.m. of the 1st and 2nd day) with: a) subjective sleepiness ratings; b) EEG recordings; c) SEPs recordings; d) behavioral vigilance responses.

Results: A clear enhancement of cortical excitability after SD was indexed by: (a) an amplitude increase of different SEPs component in S1; (b) higher voltage in occipital (around 35-43 ms) and fronto-central areas (around 47-62 ms). Circadian fluctuations did not affect cortical excitability. Voltage changes in S1 were strongly related with post-SD fluctuations of subjective and behavioral sleepiness.

Conclusions: Sleep may have a role in keeping cortical excitability at optimal (namely below potentially dangerous) levels for the human brain, rebalancing progressive changes in cortical responsiveness to incoming inputs occurred during time spent awake. On the other hand, higher level of cortical responsiveness after sleep loss may be one of the mechanisms accounting for post-SD alterations in vigilance and behavior.

Keywords: Human cortical excitability; Sleep deprivation; Somatosensory evoked potentials (SEPs).

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Brain Mapping / methods*
Electric Stimulation / methods
Evoked Potentials, Somatosensory / physiology*
Humans
Male
Median Nerve / physiology*
Sleep / physiology*
Sleep Deprivation / diagnosis
Sleep Deprivation / physiopathology*
Sleep Deprivation / psychology
Somatosensory Cortex / physiology*
Young Adult