Functional connectivity of fractal and oscillatory cortical activity is distinct

Abstract

Electrophysiological signals of cortical population activity contain oscillatory and fractal (1/frequency) components. However, the relationship between these components is unclear. To address this, we investigated human resting-state MEG recordings. We applied combined source-analysis, signal orthogonalization and irregular-resampling autospectral analysis (IRASA) to separate oscillatory and fractal components of the MEG signals at the cortical source-level. We then compared the spatial correlation structure of fractal and oscillatory components across the human cortex. We found that these correlation structures differed, which suggests different mechanisms underlying fractal and oscillatory population signal components.