title: Directing eye gaze enhances auditory spatial cue discrimination.
abstract: The present study demonstrates, for the first time, a specific enhancement of auditory spatial cue discrimination due to eye gaze. Whereas the region of sharpest visual acuity, called the fovea, can be directed at will by moving one's eyes, auditory spatial information is derived primarily from head-related acoustic cues. Past auditory studies have found better discrimination in front of the head [1-3] but have not manipulated subjects' gaze, thus overlooking potential oculomotor influences. Electrophysiological studies have shown that the inferior colliculus, a critical auditory midbrain nucleus, shows visual and oculomotor responses [4-6] and modulations of auditory activity [7-9], and that auditory neurons in the superior colliculus show shifting receptive fields [10-13]. How the auditory system leverages this crossmodal information at the behavioral level remains unknown. Here we directed subjects' gaze (with an eccentric dot) or auditory attention (with lateralized noise) while they performed an auditory spatial cue discrimination task. We found that directing gaze toward a sound significantly enhances discrimination of both interaural level and time differences, whereas directing auditory spatial attention does not. These results show that oculomotor information variably enhances auditory spatial resolution even when the head remains stationary, revealing a distinct behavioral benefit possibly arising from auditory-oculomotor interactions at an earlier level of processing than previously demonstrated.
authors.affiliation: Institute for Learning and Brain Sciences, University of Washington, 1715 NE Columbia Road, Portage Bay Building, Box 357988, Seattle, WA 98195, USA.
authors.forename: Ross K
authors.initials: RK
authors.lastname: Maddox
authors.affiliation: Institute for Learning and Brain Sciences, University of Washington, 1715 NE Columbia Road, Portage Bay Building, Box 357988, Seattle, WA 98195, USA.
authors.forename: Dean A
authors.initials: DA
authors.lastname: Pospisil
authors.affiliation: Department of Speech and Hearing Sciences, University of Washington, 1417 NE 42(nd) Street, Eagleson Hall, Box 354875, Seattle, WA 98105, USA; Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21(st) Avenue South, Room 8310, Nashville, TN 37232, USA.
authors.forename: G Christopher
authors.initials: GC
authors.lastname: Stecker
authors.affiliation: Institute for Learning and Brain Sciences, University of Washington, 1715 NE Columbia Road, Portage Bay Building, Box 357988, Seattle, WA 98195, USA; Department of Speech and Hearing Sciences, University of Washington, 1417 NE 42(nd) Street, Eagleson Hall, Box 354875, Seattle, WA 98105, USA. Electronic address: akclee@uw.edu.
authors.forename: Adrian K C
authors.initials: AK
authors.lastname: Lee
mesh_terms: D000328:Adult; D001288:Attention; D001307:Auditory Perception / Q000502:physiology*; D003463:Cues; D005133:Eye Movements; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D013017:Sound Localization