TMS-Induced Cortical Potentiation during Wakefulness Locally Increases Slow Wave Activity during Sleep

• Published in: PloS one Vol. 2; no. 3; p. e276
• Main Authors: Huber, Reto, Esser, Steve K., Ferrarelli, Fabio, Massimini, Marcello, Peterson, Michael J., Tononi, Giulio
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07.03.2007; Public Library of Science (PLoS)
• Subjects: Brain; Brain Mapping - methods; Cerebral Cortex - physiology; Cortex; Cortex (motor); Cortex (premotor); EEG; Electrodes; Electroencephalography; Electromagnetism; Evoked Potentials - physiology; Homeostasis; Human subjects; Humans; Hypotheses; Laws, regulations and rules; Long-Term Potentiation - physiology; Magnetic fields; Magnetic resonance; Magnetic resonance imaging; Medical imaging; Motor Cortex - physiology; Neuroscience; Neuroscience/Neural Homeostasis; Neuroscience/Neuronal and Glial Cell Biology; Plasticity; Potentiation; Psychiatry; Sleep; Sleep - physiology; Sleep and wakefulness; Sleep Stages - physiology; Studies; Time Factors; Tomography; Transcranial Magnetic Stimulation; Wakefulness; Wakefulness - physiology; United States > US; Wisconsin
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0000276

Sleep slow wave activity (SWA) is thought to reflect sleep need, increasing in proportion to the length of prior wakefulness and decreasing during sleep. However, the process responsible for SWA regulation is not known. We showed recently that SWA increases locally after a learning task involving a circumscribed brain region, suggesting that SWA may reflect plastic changes triggered by learning. To test this hypothesis directly, we used transcranial magnetic stimulation (TMS) in conjunction with high-density EEG in humans. We show that 5-Hz TMS applied to motor cortex induces a localized potentiation of TMS-evoked cortical EEG responses. We then show that, in the sleep episode following 5-Hz TMS, SWA increases markedly (+39.1+/-17.4%, p<0.01, n = 10). Electrode coregistration with magnetic resonance images localized the increase in SWA to the same premotor site as the maximum TMS-induced potentiation during wakefulness. Moreover, the magnitude of potentiation during wakefulness predicts the local increase in SWA during sleep. These results provide direct evidence for a link between plastic changes and the local regulation of sleep need.