Resting oscillations and cross-frequency coupling in the human posteromedial cortex.
Using rare intracranial recordings from the posterior interhemispheric region of the human brain, we explored the oscillatory properties of the posteromedial cortex (PMC) during rest. The PMC is a core structure of the default mode network, which is known for its higher activity during the resting state. We found that resting PMC spectral power peaked in the theta band range (4-7 Hz) and was clearly distinguishable from adjacent cortical sites in the occipital lobe displaying peaks in the alpha band range (8-12 Hz). Additionally, the phase of PMC theta oscillations modulated the amplitude of ongoing high gamma (70-180 Hz) activity during the resting state. The magnitude of this cross-frequency modulation was shown to fluctuate at time scales comparable to those observed in functional neuroimaging studies of intrinsic functional connectivity networks (~0.1 Hz). The difference of canonical oscillations in the PMC compared to its adjacent cortical sites conforms to functional specialization across anatomical boundaries. Such differences may reflect separate oscillatory preferences between networks that are functionally connected.
Laboratory of Behavioral and Cognitive Neurology, Department of Neurology and Neurological Sciences, School of Medicine, Stanford University, 300 Pasteur Drive Rm A343 Stanford, CA 94305-5235, USA.
Brett L
BL
Foster
Josef
J
Parvizi
D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D055724:Electrophysiological Phenomena; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008297:Male; D012146:Rest / Q000502:physiology