title: Spatial representations of temporal and spectral sound cues in human auditory cortex.
abstract: Natural and behaviorally relevant sounds are characterized by temporal modulations of their waveforms, which carry important cues for sound segmentation and communication. Still, there is little consensus as to how this temporal information is represented in auditory cortex. Here, by using functional magnetic resonance imaging (fMRI) optimized for studying the auditory system, we report the existence of a topographically ordered spatial representation of temporal sound modulation rates in human auditory cortex. We found a topographically organized sensitivity within auditory cortex to sounds with varying modulation rates, with enhanced responses to lower modulation rates (2 and 4 Hz) on lateral parts of Heschl's gyrus (HG) and faster modulation rates (16 and 32 Hz) on medial HG. The representation of temporal modulation rates was distinct from the representation of sound frequencies (tonotopy) that was orientated roughly orthogonal. Moreover, the combination of probabilistic anatomical maps with a previously proposed functional delineation of auditory fields revealed that the distinct maps of temporal and spectral sound features both prevail within two presumed primary auditory fields hA1 and hR. Our results reveal a topographically ordered representation of temporal sound cues in human primary auditory cortex that is complementary to maps of spectral cues. They thereby enhance our understanding of the functional parcellation and organization of auditory cortical processing.
authors.affiliation: Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, Zurich University Hospital of Psychiatry, Zurich, Switzerland. Electronic address: marcus.herdener@bli.uzh.ch.
authors.forename: Marcus
authors.initials: M
authors.lastname: Herdener
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Esposito
authors.forename: Klaus
authors.initials: K
authors.lastname: Scheffler
authors.forename: Peter
authors.initials: P
authors.lastname: Schneider
authors.forename: Nikos K
authors.initials: NK
authors.lastname: Logothetis
authors.forename: Kamil
authors.initials: K
authors.lastname: Uludag
authors.forename: Christoph
authors.initials: C
authors.lastname: Kayser
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001931:Brain Mapping; D003463:Cues; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D010898:Pitch Perception / Q000502:physiology; D013017:Sound Localization / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Functional organization; Periodotopy; Temporal modulation rate; Tonotopy; fMRI