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Intracortical inhibition and facilitation upon awakening from different sleep stages: a transcranial magnetic stimulation study
Author(s) -
De Gennaro Luigi,
Bertini Mario,
Ferrara Michele,
Curcio Giuseppe,
Cristiani Riccardo,
Romei Vincenzo,
Fratello Fabiana,
Pauri Flavia,
Rossini Paolo Maria
Publication year - 2004
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.0953-816x.2004.03411.x
Subject(s) - transcranial magnetic stimulation , psychology , facilitation , slow wave sleep , neuroscience , evoked potential , wakefulness , audiology , non rapid eye movement sleep , stimulation , electroencephalography , medicine
Intracortical facilitation and inhibition, as assessed by the paired‐pulse transcranial magnetic stimulation technique with a subthreshold conditioning pulse followed by a suprathreshold test pulse, was studied upon awakening from REM and slow‐wave sleep (SWS). Ten normal subjects were studied for four consecutive nights. Intracortical facilitation and inhibition were assessed upon awakening from SWS and REM sleep, and during a presleep baseline. Independently of sleep stage at awakening, intracortical inhibition was found at 1–3‐ms interstimulus intervals and facilitation at 7–15‐ms interstimulus intervals. Motor thresholds were higher in SWS awakenings, with no differences between REM awakenings and wakefulness, while motor evoked potential amplitude to unconditioned stimuli decreased upon REM awakening as compared to the other conditions. REM sleep awakenings showed a significant increase of intracortical facilitation at 10 and 15 ms, while intracortical inhibition was not affected by sleep stage at awakening. While the dissociation between motor thresholds and motor evoked potential amplitudes could be explained by the different excitability of the corticospinal system during SWS and REM sleep, the heightened cortical facilitation upon awakening from REM sleep points to a cortical motor activation during this stage.