| Sleep slow waves are the main electrophysiological phenomenon underlying non rapid eye- movement (NREM) sleep. They are homeostatically regulated, they are thought to be linked to learning and plasticity processes and they seem to be associated with large currents in the major connectional backbone of the cortex, with many parts of the default network. Using transcranial magnetic stimulation (TMS) and high-density (hd) EEG we can measure slow waves with their origin and path of propagation, induce and measure plastic changes in the cerebral cortex and we can directly assess cortical connectivity and excitability. In my presentation I will present the results of recent experiments in which TMS/hd-EEG is used to demonstrate (i) a link between cortical plastic changes and sleep slow waves and (ii) establish the sleep slow waves as travelling waves which sweep the cerebral cortex with a definite site of origin and pattern of propagation. Thus, I will introduce novel analysis tools of the sleep EEG, provide insights into the mechanism underlying sleep slow-waves and discuss sleep functions. Taken together, the presented data may suggest a unifying mechanism linking slow waves, plasticity and cortical information integration. |
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