title: Theta oscillations accompanying concurrent auditory stream segregation.
abstract: The ability to isolate a single sound source among concurrent sources is crucial for veridical auditory perception. The present study investigated the event-related oscillations evoked by complex tones, which could be perceived as a single sound and tonal complexes with cues promoting the perception of two concurrent sounds by inharmonicity, onset asynchrony, and/or perceived source location difference of the components tones. In separate task conditions, participants performed a visual change detection task (visual control), watched a silent movie (passive listening) or reported for each tone whether they perceived one or two concurrent sounds (active listening). In two time windows, the amplitude of theta oscillation was modulated by the presence vs. absence of the cues: 60-350ms/6-8Hz (early) and 350-450ms/4-8Hz (late). The early response appeared both in the passive and the active listening conditions; it did not closely match the task performance; and it had a fronto-central scalp distribution. The late response was only elicited in the active listening condition; it closely matched the task performance; and it had a centro-parietal scalp distribution. The neural processes reflected by these responses are probably involved in the processing of concurrent sound segregation cues, in sound categorization, and response preparation and monitoring. The current results are compatible with the notion that theta oscillations mediate some of the processes involved in concurrent sound segregation.
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary; Center for Computational Neuroscience and Neural Technology, Boston University, United States. Electronic address: toth.brigitta@ttk.mta.hu.
authors.forename: Brigitta
authors.initials: B
authors.lastname: Tóth
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary; Department of Cognitive Science, Faculty of Natural Sciences, Budapest University of Technology and Economics, Budapest, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Kocsis
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Urbán
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary; Department of Cognitive and Neuropsychology, Institute of Psychology, University of Szeged, Szeged, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Winkler
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D013826:Theta Rhythm / Q000502:physiology*; D055815:Young Adult
keywords: Active and passive listening; Concurrent sound segregation; Object-related oscillatory activity; Theta oscillation