title: Dissociable influences of primary auditory cortex and the posterior auditory field on neuronal responses in the dorsal zone of auditory cortex.
abstract: Current models of hierarchical processing in auditory cortex have been based principally on anatomical connectivity while functional interactions between individual regions have remained largely unexplored. Previous cortical deactivation studies in the cat have addressed functional reciprocal connectivity between primary auditory cortex (A1) and other hierarchically lower level fields. The present study sought to assess the functional contribution of inputs along multiple stages of the current hierarchical model to a higher order area, the dorsal zone (DZ) of auditory cortex, in the anaesthetized cat. Cryoloops were placed over A1 and posterior auditory field (PAF). Multiunit neuronal responses to noise burst and tonal stimuli were recorded in DZ during cortical deactivation of each field individually and in concert. Deactivation of A1 suppressed peak neuronal responses in DZ regardless of stimulus and resulted in increased minimum thresholds and reduced absolute bandwidths for tone frequency receptive fields in DZ. PAF deactivation had less robust effects on DZ firing rates and receptive fields compared with A1 deactivation, and combined A1/PAF cooling was largely driven by the effects of A1 deactivation at the population level. These results provide physiological support for the current anatomically based model of both serial and parallel processing schemes in auditory cortical hierarchical organization.
authors.affiliation: Graduate Program in Neuroscience, University of Western Ontario, London, Canada; Brain and Mind Institute, Department of Psychology, University of Western Ontario, London, Canada; Cerebral Systems Laboratory, University of Western Ontario, London, Canada;
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Kok
authors.affiliation: Brain and Mind Institute, Department of Psychology, University of Western Ontario, London, Canada; Cerebral Systems Laboratory, University of Western Ontario, London, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Canada; and.
authors.forename: Daniel
authors.initials: D
authors.lastname: Stolzberg
authors.affiliation: Brain and Mind Institute, Department of Psychology, University of Western Ontario, London, Canada; Cerebral Systems Laboratory, University of Western Ontario, London, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Canada; and.
authors.forename: Trecia A
authors.initials: TA
authors.lastname: Brown
authors.affiliation: Graduate Program in Neuroscience, University of Western Ontario, London, Canada; Brain and Mind Institute, Department of Psychology, University of Western Ontario, London, Canada; Cerebral Systems Laboratory, University of Western Ontario, London, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Canada; and National Centre for Audiology, University of Western Ontario, London, Canada steve.lomber@uwo.ca.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Lomber
mesh_terms: D000161:Acoustic Stimulation; D000758:Anesthesia; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D002415:Cats; D005260:Female; D008297:Male; D009474:Neurons / Q000502:physiology*; D013696:Temperature
keywords: auditory cortex; auditory pathways; hierarchy; reversible deactivation