Poster #: 9
Topic: Attention and distraction
Friday, Sep 11, 2015
Auditory distractors modulate oscillatory power prior to visual targets – the neural basis for impaired target detection?
1University of Trento, Mattarello, Italy
2CIMeC, University of Trento, Mattarello, Italy
3University of Leipzig, Leipzig, Germany
Rarely occurring novel sounds (distractors) often impair task performance, even when targets stem from another (e.g., visual) modality. To better understand the underlying neural mechanisms we analyzed the effect of distractors on neural activity in the pre-target period. MEG data were collected within an auditory-visual distraction paradigm, in which the visual target was preceded by either a standard or a distractor sound. Even though participants ignored the auditory input, the distractor but not the standard sounds impaired task performance. Distractors evoked mismatch negativity (MMNm) and P3a activity, indexing the brain’s error signal to this sound and involuntary attention capture. Impaired target performance due to a preceding distractor was indicated by longer reaction times. The current results extend those previously published by re-examining the effects of the distractor on visual processing before the target occurs. The current approach is motivated by research showing that different brain states (indexed by different patterns in oscillatory activity) can influence stimulus processing. Accordingly, we investigated oscillatory power in the time window before the visual target when preceded by either standard or distractor. Interestingly, we found decreased power for distractors compared to standards in the upper alpha to beta range (14-26 Hz) with a posterior distribution. This suggests that auditory distractors change oscillatory patterns in visual areas before the visual target occurs. This could be the neural basis for the impaired visual task performance.