When individuals are required to switch rapidly from execution of one task to another, goal-related task networks and attentional mechanisms are engaged to reconfigure task-specific networks, suppressing activity within circuits responsible for performance of the old task and amplifying preparatory neural processes for the anticipated novel task. That is, competition between two potential task-set configurations must be resolved so that an effective strategy shift can be enacted. In this study, we investigated the neural processes involved in switching between visual and auditory tasks, where both potentially task-relevant sensory inputs were presented simultaneously. As such, the two sensory systems were competing for processing resources. We were specifically interested in the role of oscillatory neural mechanisms in these task-set reconfigurations. We principally examined alpha-band oscillatory activity (10-14 Hz) in the periods preceding switches of task, compared to periods preceding repeats of a given sensory task. The need to switch tasks across the senses resulted in significant behavioral costs (slower and less accurate performing) than when just one task was engaged in for protracted periods of time. Anticipatory alpha-band suppressive mechanisms, in the form of substantially amplified oscillatory synchronizations, were implicated in the successful switching of attention to the auditory stream. In contrast, vigorous alpha-band desynchronization characterized periods preceding switches to the visual domain. The major cortical generators of this alpha-band activity were found in parieto-occipital and fronto-central regions, suggesting involvement of the well-known fronto-parietal attention network in resolving competition between two competing sensory tasks.

attention; competition; oscillations; alpha-band; task-switching;