Functional roles of 10 Hz alpha-band power modulating engagement and disengagement of cortical networks in a complex visual motion task.

Kunjan D Rana,Lucia M Vaina,Lawrence M Ward

doi:10.1371/journal.pone.0107715

Abstract

Alpha band power, particularly at the 10 Hz frequency, is significantly involved in sensory inhibition, attention modulation, and working memory. However, the interactions between cortical areas and their relationship to the different functional roles of the alpha band oscillations are still poorly understood. Here we examined alpha band power and the cortico-cortical interregional phase synchrony in a psychophysical task involving the detection of an object moving in depth by an observer in forward self-motion. Wavelet filtering at the 10 Hz frequency revealed differences in the profile of cortical activation in the visual processing regions (occipital and parietal lobes) and in the frontoparietal regions. The alpha rhythm driving the visual processing areas was found to be asynchronous with the frontoparietal regions. These findings suggest a decoupling of the 10 Hz frequency into separate functional roles: sensory inhibition in the visual processing regions and spatial attention in the frontoparietal regions.

Highlights

Cortical fluctuations between 8–14 Hz are perhaps the most studied brain oscillations since the early days of electrophysiological recordings [1], yet their physiological role remains unclear
Behavioral results Behavioral performance was assessed as a percentage of correct responses for object motion detection in the visual motion task (VS) task, and for discrimination of the direction of the pattern of radial motion in the MT+ Localizer (MTLoc) task
Our group has previously demonstrated that flow parsing could be the effective mechanism by which an observer in forward motion can detect an object moving in depth Here we show that it does so in the first 300 ms of the stimulus in MT+ through observing 10-Hz alpha band power changes, and linking the changes to alpha inhibition

Summary

Introduction

Cortical fluctuations between 8–14 Hz (alpha frequency band) are perhaps the most studied brain oscillations since the early days of electrophysiological recordings [1], yet their physiological role remains unclear. Numerous studies involving both direct neuronal recordings and noninvasive EEG (electroencephalography) and MEG (magnetoencephalography) approaches have investigated the nature of this neural oscillation and its contributions to cognitive functions, including memory formation, attention control, and anticipatory recruitment of neurons involved in perceptual or cognitive tasks (for reviews see [2,3,4,5]). There is evidence that inhibitory alpha power precedes the involvement of cortical regions in task-related functions [13,14]

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