title: Human Auditory and Adjacent Nonauditory Cerebral Cortices Are Hypermetabolic in Tinnitus as Measured by Functional Near-Infrared Spectroscopy (fNIRS).
abstract: Tinnitus is the phantom perception of sound in the absence of an acoustic stimulus. To date, the purported neural correlates of tinnitus from animal models have not been adequately characterized with translational technology in the human brain. The aim of the present study was to measure changes in oxy-hemoglobin concentration from regions of interest (ROI; auditory cortex) and non-ROI (adjacent nonauditory cortices) during auditory stimulation and silence in participants with subjective tinnitus appreciated equally in both ears and in nontinnitus controls using functional near-infrared spectroscopy (fNIRS). Control and tinnitus participants with normal/near-normal hearing were tested during a passive auditory task. Hemodynamic activity was monitored over ROI and non-ROI under episodic periods of auditory stimulation with 750 or 8000 Hz tones, broadband noise, and silence. During periods of silence, tinnitus participants maintained increased hemodynamic responses in ROI, while a significant deactivation was seen in controls. Interestingly, non-ROI activity was also increased in the tinnitus group as compared to controls during silence. The present results demonstrate that both auditory and select nonauditory cortices have elevated hemodynamic activity in participants with tinnitus in the absence of an external auditory stimulus, a finding that may reflect basic science neural correlates of tinnitus that ultimately contribute to phantom sound perception.
authors.affiliation: Department of Otolaryngology/Head and Neck Surgery, Kresge Hearing Research Institute, The University of Michigan, 1100 W Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Mohamad
authors.initials: M
authors.lastname: Issa
authors.affiliation: Center for Human Growth and Development, The University of Michigan, 1100 W Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bisconti
authors.affiliation: Center for Human Growth and Development, The University of Michigan, 1100 W Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Ioulia
authors.initials: I
authors.lastname: Kovelman
authors.affiliation: Department of Otolaryngology/Head and Neck Surgery, Kresge Hearing Research Institute, The University of Michigan, 1100 W Medical Center Drive, Ann Arbor, MI 48109, USA; Center for Human Growth and Development, The University of Michigan, 1100 W Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Kileny
authors.affiliation: Department of Otolaryngology/Head and Neck Surgery, Kresge Hearing Research Institute, The University of Michigan, 1100 W Medical Center Drive, Ann Arbor, MI 48109, USA; Center for Human Growth and Development, The University of Michigan, 1100 W Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Gregory J
authors.identifier: 0000-0002-5574-7385
authors.initials: GJ
authors.lastname: Basura
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000378:metabolism* / Q000503:physiopathology*; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000378:metabolism* / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D019265:Spectroscopy, Near-Infrared; D014012:Tinnitus / Q000378:metabolism* / Q000503:physiopathology*