title: Sleep deprivation affects somatosensory cortex excitability as tested through median nerve stimulation.
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.
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Maurizio
authors: M
authors: Gorgoni
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Fabio
authors: F
authors: Ferlazzo
authors: Department of Psychology, University of Bologna, Bologna, Italy.
authors: Fabio
authors: F
authors: Moroni
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Aurora
authors: A
authors: D'Atri
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Stefania
authors: S
authors: Donarelli
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Stefania
authors: S
authors: Fanelli
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Isabella
authors: I
authors: Gizzi Torriglia
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Giulia
authors: G
authors: Lauri
authors: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors: Michele
authors: M
authors: Ferrara
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors: Cristina
authors: C
authors: Marzano
authors: Institute of Neurology, Catholic University of The Sacred Heart, Rome, Italy; IRCCS San Raffaele Pisana, Rome, Italy.
authors: Paolo Maria
authors: PM
authors: Rossini
authors: IRCCS Bonino-Pulejo, Messina, Italy.
authors: Placido
authors: P
authors: Bramanti
authors: Department of Psychology, "Sapienza" University of Rome, Rome, Italy; IRCCS San Raffaele Pisana, Rome, Italy. Electronic address: luigi.degennaro@uniroma1.it.
authors: Luigi
authors: L
authors: De Gennaro
mesh_terms: D001931:Brain Mapping / Q000379:methods*; D004558:Electric Stimulation / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D013003:Somatosensory Cortex / Q000502:physiology*; D055815:Young Adult
keywords: Human cortical excitability; Sleep deprivation; Somatosensory evoked potentials (SEPs)