title: Evidence for distinct human auditory cortex regions for sound location versus identity processing.
abstract: Neurophysiological animal models suggest that anterior auditory cortex (AC) areas process sound identity information, whereas posterior ACs specialize in sound location processing. In humans, inconsistent neuroimaging results and insufficient causal evidence have challenged the existence of such parallel AC organization. Here we transiently inhibit bilateral anterior or posterior AC areas using MRI-guided paired-pulse transcranial magnetic stimulation (TMS) while subjects listen to Reference/Probe sound pairs and perform either sound location or identity discrimination tasks. The targeting of TMS pulses, delivered 55-145 ms after Probes, is confirmed with individual-level cortical electric-field estimates. Our data show that TMS to posterior AC regions delays reaction times (RT) significantly more during sound location than identity discrimination, whereas TMS to anterior AC regions delays RTs significantly more during sound identity than location discrimination. This double dissociation provides direct causal support for parallel processing of sound identity features in anterior AC and sound location in posterior AC.
authors.affiliation: Harvard Medical School-Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA.
authors.forename: Jyrki
authors.initials: J
authors.lastname: Ahveninen
authors.forename: Samantha
authors.initials: S
authors.lastname: Huang
authors.forename: Aapo
authors.initials: A
authors.lastname: Nummenmaa
authors.forename: John W
authors.initials: JW
authors.lastname: Belliveau
authors.forename: An-Yi
authors.initials: AY
authors.lastname: Hung
authors.forename: Iiro P
authors.initials: IP
authors.lastname: Jääskeläinen
authors.forename: Josef P
authors.initials: JP
authors.lastname: Rauschecker
authors.forename: Stephanie
authors.initials: S
authors.lastname: Rossi
authors.forename: Hannu
authors.initials: H
authors.lastname: Tiitinen
authors.forename: Tommi
authors.initials: T
authors.lastname: Raij
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D046709:Pattern Recognition, Physiological / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time; D013016:Sound; D013017:Sound Localization / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation