Poster C109, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Neurophysiological Effects of the Presence of an Irrelevant Visual Stimulus on Auditory Neural Activity
Kristina Backer1, Andrew S. Kessler1, Laurel A. Lawyer1, Lee M. Miller1, David P. Corina1; 1University of California, Davis
It is well-known that top-down selective attention can modulate brain activity at the level of sensory cortex. However, much less is known about cross-modal interactions that may occur due to exogenous mechanisms of attention. Thus, in this study, we used electroencephalography (EEG) to assess how auditory activity may be affected by the presence of an unrelated, salient visual stimulus. Twenty-five young adult participants passively watched a cartoon, during the presentation of auditory and visual stimuli. The auditory stimuli comprised engineered continuous speech that was designed to elicit both auditory steady-state responses (ASSRs, 41 Hz) and auditory evoked potentials (AEPs). Visual stimuli consisted of two checkered rings that surrounded the cartoon and flickered at a rate of 7.5 or 12 Hz during brief intervals. Sometimes, only the auditory stimulus was present (A-Only); at other times, both the auditory and visual stimuli were concurrent (AV). EEG data were time-locked to voicing onsets in the auditory stimulus, and epochs were separated according to the presence (AV) or absence (A-Only) of the visual flickering. The ASSR was significantly stronger for the AV than A-Only condition. The AEPs showed significant differences between the AV and A-Only conditions, in late sustained responses (~150-450 ms after voicing onset) and in their corresponding topographical patterns. Thus, the presence of a task-irrelevant visual stimulus influenced auditory neural activity, suggesting the contribution of a cross-modal sensory gating mechanism.
Topic Area: PERCEPTION & ACTION: Audition