Biphasic Alpha Lateralization in Pro- and Anti-Saccade task: Electrophysiological Evidence of Overlapping Attentional Mechanisms.
Daniel Belyusar, Adam C Snyder, Hans-Peter Frey, John J Foxe

Last modified: 2011-09-02

Abstract


The transition between covert and overt attention is exemplified in visual saccades. While some electrophysiological evidence suggests a common mechanism for shifting attention and eyes (Eimer et al., 2007) other results favors unique cortical mechanisms (Van der Lubbe et al., 2006). To address the seemingly contradictory results we considered a known electrophysiological correlate of covert attention in a saccade paradigm. Previous research suggests that changes in alpha-band (8-14Hz) power correlate to preparatory states when one is required to suppress activation in tasks involving attentional shifts (Worden et al., 2000). Increases in alpha levels have also been associated with active attentional suppression (Kelly et al., 2006). Our results indicate Alpha-band modulations to both cue and target location across auditory and visual modalities. This design eliminates the potential working-memory confounds in traditional cue-delay saccade tasks and isolating the effects specifically related to a saccade reaction. Results suggest a biphasic pattern of oscillatory activity with rapid ipsilateral increases in alpha power in response to stimulus onset. The Alpha coherency quickly shifts to saccade-related laterialization. This second phase appears topographically similar across stimulus modality. These results suggest multiple roles for alpha rhythms in both sensory and motor processes.

References


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