Topic: IRASA

Human direct brain recordings have implicated 4-8 Hz theta-band activity in a wide range of cognitive processes including spatial navigation, working memory, and associative recall (Kahana et al. (2001); Nyhus & Curran (2010)). Yet, many highly-powered memory studies indicate that good memory appears during periods of reduced theta and alpha (8-12 Hz) activity and enhanced high-frequency (>40 Hz activity), a pattern known as the spectral tilt (Burkeet al., 2015). In a meta-analysis of prior work, Herweg et al. (2020) suggest several possible resolutions to these discrepant results:

This study contributes to the investigation of true oscillatory activity within neurophysiological data, amidst the backdrop of aperiodic neural activity. Donoghue et al. (2020) showed that in MEEG narrowband power peaks can be distorted due to interactions with the aperiodic component of the power spectrum, complicating interpretations of oscillatory peaks. We validated the separation of aperiodic and oscillatory components in EEG data from three conditions — eyes open, eyes closed, and waiting for visual tasks —using IRASA (Irregular-Resampling Auto-Spectral Analysis, Wen & Liu, 2016) an