title: Arm immobilization causes cortical plastic changes and locally decreases sleep slow wave activity.
abstract: Sleep slow wave activity (SWA) is thought to reflect sleep need, increasing after wakefulness and decreasing after sleep. We showed recently that a learning task involving a circumscribed brain region produces a local increase in sleep SWA. We hypothesized that increases in cortical SWA reflect synaptic potentiation triggered by learning. To further investigate the link between synaptic plasticity and sleep, we asked whether a procedure leading to synaptic depression would cause instead a decrease in sleep SWA. We show here that if a subject's arm is immobilized during the day, motor performance deteriorates and both somatosensory and motor evoked potentials decrease over contralateral sensorimotor cortex, indicative of local synaptic depression. Notably, during subsequent sleep, SWA over the same cortical area is markedly reduced. Thus, cortical plasticity is linked to local sleep regulation without learning in the classical sense. Moreover, when synaptic strength is reduced, local sleep need is also reduced.
authors.affiliation: Department of Psychiatry, University of Wisconsin, Madison, Wisconsin 53719, USA.
authors.forename: Reto
authors.initials: R
authors.lastname: Huber
authors.forename: M Felice
authors.initials: MF
authors.lastname: Ghilardi
authors.forename: Marcello
authors.initials: M
authors.lastname: Massimini
authors.forename: Fabio
authors.initials: F
authors.lastname: Ferrarelli
authors.forename: Brady A
authors.initials: BA
authors.lastname: Riedner
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Peterson
authors.forename: Giulio
authors.initials: G
authors.lastname: Tononi
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001132:Arm / Q000294:innervation / Q000503:physiopathology*; D004569:Electroencephalography; D006801:Humans; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D012149:Restraint, Physical; D012890:Sleep / Q000502:physiology*; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013647:Task Performance and Analysis