title: Salient, Irrelevant Sounds Reflexively Induce Alpha Rhythm Desynchronization in Parallel with Slow Potential Shifts in Visual Cortex.
abstract: Recent findings suggest that a salient, irrelevant sound attracts attention to its location involuntarily and facilitates processing of a colocalized visual event [McDonald, J. J., Störmer, V. S., Martinez, A., Feng, W. F., & Hillyard, S. A. Salient sounds activate human visual cortex automatically. Journal of Neuroscience, 33, 9194-9201, 2013]. Associated with this cross-modal facilitation is a sound-evoked slow potential over the contralateral visual cortex termed the auditory-evoked contralateral occipital positivity (ACOP). Here, we further tested the hypothesis that a salient sound captures visual attention involuntarily by examining sound-evoked modulations of the occipital alpha rhythm, which has been strongly associated with visual attention. In two purely auditory experiments, lateralized irrelevant sounds triggered a bilateral desynchronization of occipital alpha-band activity (10-14 Hz) that was more pronounced in the hemisphere contralateral to the sound's location. The timing of the contralateral alpha-band desynchronization overlapped with that of the ACOP (∼240-400 msec), and both measures of neural activity were estimated to arise from neural generators in the ventral-occipital cortex. The magnitude of the lateralized alpha desynchronization was correlated with ACOP amplitude on a trial-by-trial basis and between participants, suggesting that they arise from or are dependent on a common neural mechanism. These results support the hypothesis that the sound-induced alpha desynchronization and ACOP both reflect the involuntary cross-modal orienting of spatial attention to the sound's location.
authors.affiliation: Harvard University.
authors.forename: Viola
authors.initials: V
authors.lastname: Störmer
authors.affiliation: SooChow University, China.
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Feng
authors.affiliation: University of California at San Diego.|Nathan Kline Institute for Psychiatric Research, Orangeburg, NY.
authors.forename: Antigona
authors.initials: A
authors.lastname: Martinez
authors.affiliation: Simon Fraser University.
authors.forename: John
authors.initials: J
authors.lastname: McDonald
authors.affiliation: University of California at San Diego.
authors.forename: Steven
authors.initials: S
authors.lastname: Hillyard
mesh_terms: D000293:Adolescent; D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D003344:Cortical Synchronization / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult