Introduction: Sleep electroencephalogram (EEG) brain oscillations in the slow-frequency range increase/decrease locally after tasks involving circumscribed cortical regions. It has been hypothesized that these changes reflect plastic re-organizations, triggered by learning and mediated by long-term potentiation (LTP), which may regulate local sleep need. Here, we test the hypothesis that waking potentiation of synaptic transmission in the motor cortex affect EEG activity in specific cortical circuits during subsequent sleep. Waking potentiation has been obtained by a Hebbian stimulation paradigm inducing cortical plasticity in humans, which resembles associative timing-dependent LTP. The paradigm consists of repetitive pairing of median nerve stimulation with transcranial magnetic stimulation over the controlateral motor cortex, which increases cortical excitability at interstimulus intervals of 25 ms (paired associative stimulation at 25 ms, PAS-25). Cortical distribution of sleep EEG power following PAS-25 has been compared to that following a control paradigm with intervals of 50 ms (PAS-50). Methods: We recorded full night EEG in ten healthy subjects undergoing a four-day sleep study. In the third and fourth nights, subjects were submitted to a presleep PAS-25 or to a PAS-50. Experimental manipulation of corticospinal tract excitability induced a 48% increase in amplitude of motor evoked potentials (MEPs) only with PAS-25. This waking LTP-like potentiation affected delta and theta power, in both NREM and REM sleep. Slow-wave activity (SWA) increases in some frontal and prefrontal derivations and decreases at sites neighboring and controlateral to the stimulated left motor cortex. The magnitude of increased PAS- 25 MEP amplitude also predicts enhancements of SWA in prefrontal regions. Conclusions: An increased synaptic strength, presumably induced by the LTP-like paradigm, leads to changes in local sleep
Cortical plasticity induced by transcranial magnetic stimulation during wakefulness affects EEG activity during sleep / DE GENNARO, Luigi; Fratello, Fabiana; Marzano, Cristina; Moroni, Fabio; Curcio, G; Tempesta, D; Ferrara, M.. - In: JOURNAL OF SLEEP RESEARCH. - ISSN 1365-2869. - 17:(2008), pp. 458-458.
Cortical plasticity induced by transcranial magnetic stimulation during wakefulness affects EEG activity during sleep.
DE GENNARO, Luigi;FRATELLO, FABIANA;MARZANO, CRISTINA;MORONI, FABIO;
2008
Abstract
Introduction: Sleep electroencephalogram (EEG) brain oscillations in the slow-frequency range increase/decrease locally after tasks involving circumscribed cortical regions. It has been hypothesized that these changes reflect plastic re-organizations, triggered by learning and mediated by long-term potentiation (LTP), which may regulate local sleep need. Here, we test the hypothesis that waking potentiation of synaptic transmission in the motor cortex affect EEG activity in specific cortical circuits during subsequent sleep. Waking potentiation has been obtained by a Hebbian stimulation paradigm inducing cortical plasticity in humans, which resembles associative timing-dependent LTP. The paradigm consists of repetitive pairing of median nerve stimulation with transcranial magnetic stimulation over the controlateral motor cortex, which increases cortical excitability at interstimulus intervals of 25 ms (paired associative stimulation at 25 ms, PAS-25). Cortical distribution of sleep EEG power following PAS-25 has been compared to that following a control paradigm with intervals of 50 ms (PAS-50). Methods: We recorded full night EEG in ten healthy subjects undergoing a four-day sleep study. In the third and fourth nights, subjects were submitted to a presleep PAS-25 or to a PAS-50. Experimental manipulation of corticospinal tract excitability induced a 48% increase in amplitude of motor evoked potentials (MEPs) only with PAS-25. This waking LTP-like potentiation affected delta and theta power, in both NREM and REM sleep. Slow-wave activity (SWA) increases in some frontal and prefrontal derivations and decreases at sites neighboring and controlateral to the stimulated left motor cortex. The magnitude of increased PAS- 25 MEP amplitude also predicts enhancements of SWA in prefrontal regions. Conclusions: An increased synaptic strength, presumably induced by the LTP-like paradigm, leads to changes in local sleepI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
