Poster Session A, Saturday, March 23, 1:30 pm - 3:30 pm, Pacific Concourse
Temporal foreknowledge enhances modulation of lateralized alpha oscillations during spatial attention
Malte Wöstmann1, Burkhard Maess2, Jonas Obleser1; 1Department of Psychology, University of Lübeck, Germany, 2Max-Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
Spatial attention induces lateralization of neural alpha oscillations (8–12 Hz): Alpha power increases versus decreases in the hemisphere ipsi- versus contra-lateral to attention, respectively. While the deployment of alpha lateralization in service of spatial attention is well-established, much less is known about human abilities to deploy alpha lateralization in time, and to thus exploit alpha power as a spatio-temporal filter. In a dichotic listening task, participants (N = 20) were simultaneously presented with five spoken numbers on either ear. Spatial attention was triggered by a tone presented on one ear to indicate whether numbers on the left or right side were to-be-attended. Temporal foreknowledge was provided by a visual cue in the beginning of each trial, which was either informative and indicated the to-be-probed number position (70% valid) or uninformative. Behavioral results show that participants used temporal foreknowledge to guide attention: Recognition of a number from the to-be-attended side was enhanced when this position was validly cued, compared to invalid and uninformative cues. In the magnetoencephalogram (MEG), spatial attention induced lateralization of alpha power in trials with both temporal cues. However, modulation of alpha lateralization in temporal synchrony with spoken numbers was stronger following informative compared to uninformative cues. Critically, we found that listeners increased their modulation of alpha power specifically around onsets of cued versus non-cued numbers. Results indicate that the deployment of spatial attention synchronizes with the stimulus and that temporal expectation of a task-relevant event increases the magnitude of synchronized alpha modulation.
Topic Area: ATTENTION: Auditory