title: Integrated processing of spatial cues in human auditory cortex.
abstract: Human sound source localization relies on acoustical cues, most importantly, the interaural differences in time and level (ITD and ILD). For reaching a unified representation of auditory space the auditory nervous system needs to combine the information provided by these two cues. In search for such a unified representation, we conducted a magnetoencephalography (MEG) experiment that took advantage of the location-specific adaptation of the auditory cortical N1 response. In general, the attenuation caused by a preceding adaptor sound to the response elicited by a probe depends on their spatial arrangement: if the two sounds coincide, adaptation is stronger than when the locations differ. Here, we presented adaptor-probe pairs that contained different localization cues, for instance, adaptors with ITD and probes with ILD. We found that the adaptation of the N1 amplitude was location-specific across localization cues. This result can be explained by the existence of auditory cortical neurons that are sensitive to sound source location independent on which cue, ITD or ILD, provides the location information. Such neurons would form a cue-independent, unified representation of auditory space in human auditory cortex.
authors.affiliation: Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O. Box 12200, FI-00076 Aalto, Finland; MEG Core, Aalto NeuroImaging, Aalto University School of Science, Finland. Electronic address: nelli.salminen@aalto.fi.
authors.forename: Nelli H
authors.initials: NH
authors.lastname: Salminen
authors.affiliation: Audio Information Processing, Technische Universität München, 80333 Munich, Germany.
authors.forename: Marko
authors.initials: M
authors.lastname: Takanen
authors.affiliation: Department of Signal Processing and Acoustics, Aalto University School of Electrical Engineering, P.O. Box 13000, FI-00076 Aalto, Finland.
authors.forename: Olli
authors.initials: O
authors.lastname: Santala
authors.affiliation: Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, P.O. Box 12200, FI-00076 Aalto, Finland.
authors.forename: Jarkko
authors.initials: J
authors.lastname: Lamminsalo
authors.affiliation: Department of Signal Processing and Acoustics, Aalto University School of Electrical Engineering, P.O. Box 13000, FI-00076 Aalto, Finland.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Altoè
authors.affiliation: Department of Signal Processing and Acoustics, Aalto University School of Electrical Engineering, P.O. Box 13000, FI-00076 Aalto, Finland.
authors.forename: Ville
authors.initials: V
authors.lastname: Pulkki
mesh_terms: D000161:Acoustic Stimulation; D000223:Adaptation, Psychological; D000328:Adult; D001299:Audiometry; D001303:Auditory Cortex / Q000502:physiology*; D001306:Auditory Pathways / Q000502:physiology; D001309:Auditory Threshold; D003463:Cues; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D011571:Psychoacoustics; D013017:Sound Localization; D013028:Space Perception; D013997:Time Factors
keywords: Auditory cortex; Human; Interaural level difference; Interaural time difference; Sound source localization