title: Widespread and Opponent fMRI Signals Represent Sound Location in Macaque Auditory Cortex.
abstract: In primates, posterior auditory cortical areas are thought to be part of a dorsal auditory pathway that processes spatial information. But how posterior (and other) auditory areas represent acoustic space remains a matter of debate. Here we provide new evidence based on functional magnetic resonance imaging (fMRI) of the macaque indicating that space is predominantly represented by a distributed hemifield code rather than by a local spatial topography. Hemifield tuning in cortical and subcortical regions emerges from an opponent hemispheric pattern of activation and deactivation that depends on the availability of interaural delay cues. Importantly, these opponent signals allow responses in posterior regions to segregate space similarly to a hemifield code representation. Taken together, our results reconcile seemingly contradictory views by showing that the representation of space follows closely a hemifield code and suggest that enhanced posterior-dorsal spatial specificity in primates might emerge from this form of coding.
authors.affiliation: Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Spemannstraße 36, 72072 Tübingen, Germany; Graduate School of Neural & Behavioural Sciences, International Max Planck Research School (IMPRS), University of Tübingen, Österbergstraße 3, 72074 Tübingen, Germany; Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Road, N.W. Washington, D.C., 20057, USA; Institute of Neuroscience, Henry Welcome Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. Electronic address: michael.ortiz-rios@newcastle.ac.uk.
authors.forename: Michael
authors.initials: M
authors.lastname: Ortiz-Rios
authors.affiliation: Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Spemannstraße 36, 72072 Tübingen, Germany; Graduate School of Neural & Behavioural Sciences, International Max Planck Research School (IMPRS), University of Tübingen, Österbergstraße 3, 72074 Tübingen, Germany.
authors.forename: Frederico A C
authors.initials: FAC
authors.lastname: Azevedo
authors.affiliation: Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Road, N.W. Washington, D.C., 20057, USA.
authors.forename: Paweł
authors.initials: P
authors.lastname: Kuśmierek
authors.affiliation: Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Spemannstraße 36, 72072 Tübingen, Germany.
authors.forename: Dávid Z
authors.initials: DZ
authors.lastname: Balla
authors.affiliation: Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Spemannstraße 36, 72072 Tübingen, Germany; Department of Systems Neurophysiology, Fachbereich Biologie, Technische Universität Darmstadt, Schnittspahnstraße 10, 64287, Darmstadt, Germany.
authors.forename: Matthias H
authors.initials: MH
authors.lastname: Munk
authors.affiliation: Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Spemannstraße 36, 72072 Tübingen, Germany; Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, 2610, Belgium.
authors.forename: Georgios A
authors.initials: GA
authors.lastname: Keliris
authors.affiliation: Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Spemannstraße 36, 72072 Tübingen, Germany; Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, M13 9PL, UK.
authors.forename: Nikos K
authors.initials: NK
authors.lastname: Logothetis
authors.affiliation: Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Road, N.W. Washington, D.C., 20057, USA; Institute for Advanced Study of Technische Universität München, Lichtenbergstraße 2 a, 85748 Garching, Germany.
authors.forename: Josef P
authors.initials: JP
authors.lastname: Rauschecker
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001306:Auditory Pathways / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D007839:Functional Laterality / Q000502:physiology; D008251:Macaca; D008279:Magnetic Resonance Imaging / Q000379:methods; D013016:Sound; D013017:Sound Localization / Q000502:physiology*
keywords: Auditory Cortex; Auditory Space; Functional MRI; Macaque monkey