The relationship between neural variability and neural oscillations

Abstract

Neural activity fluctuates over time, creating considerable variability across trials. This trial-by-trial neural variability is dramatically reduced ("quenched") after the presentation of sensory stimuli.Likewise, the power of neural oscillations, primarily in the alpha-beta band, is also reduced. Despite their similarity, these phenomena have been discussed independently. We hypothesized that the two phenomena are tightly coupled. To test this, we examined magnetoencephalography (MEG) recordings of healthy subjects viewing repeated presentations of a visual stimulus. The timing, amplitude, and spatial topography of variability-quenching and power suppression were remarkably similar. Neural variability quenching was eliminated by excluding the alpha-beta band from the recordings, but not by excluding other frequency-bands. Moreover, individual magnitudes of alphabeta band power explained 86% of between-subject differences in variability quenching. In contrast, inter-trial-phase-coherence (ITPC) was not correlated with variability quenching. These results reveal that neural variability quenching reflects stimulus-induced changes in the power of alpha-beta band oscillations.

Spatial attention enhances cortical tracking of quasi-rhythmic visual stimuli

“…Further evidence for this perspective comes from observations that stimulus presentation itself and the allocation of attention both reduce neural variability, a measure thought to reflect an increase in cortical signal-to-noise ratio (Arazi, Censor, & Dinstein, 2017;Arazi, Yeshurun, & Dinstein, 2019;Deco & Hugues, 2012). Interestingly, in turn, changes in neural variability seem to be tied most closely to fluctuations in the power of alpha rhythms (Daniel, Meindertsma, Arazi, Donner, & Dinstein, 2019).…”