Tinnitus and auditory cortex: using adapted functional near-infrared spectroscopy to measure resting-state functional connectivity.

Autor:	San Juan JD; Center for Human Growth and Development.; Department of Otolaryngology/Head and Neck Surgery, Kresge Hearing Research Institute., Zhai T; Department of Electric Engineering., Ash-Rafzadeh A; Center for Human Growth and Development., Hu XS; Center for Human Growth and Development.; Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA., Kim J; Center for Human Growth and Development., Filipak C; Department of Electric Engineering., Guo K; Department of Electric Engineering., Islam MN; Department of Electric Engineering., Kovelman I; Center for Human Growth and Development., Basura GJ; Center for Human Growth and Development.; Department of Otolaryngology/Head and Neck Surgery, Kresge Hearing Research Institute.
Jazyk:	angličtina
Zdroj:	Neuroreport [Neuroreport] 2021 Jan 06; Vol. 32 (1), pp. 66-75.
DOI:	10.1097/WNR.0000000000001561
Abstrakt:	Objective: Tinnitus, phantom sound perception, arises from aberrant brain activity within auditory cortex. In tinnitus animal models, auditory cortex neurons show increased spontaneous firing and neural synchrony. In humans, similar hyperactivation in auditory cortex has been displayed with functional near-infrared spectroscopy (fNIRS). Resting-state functional connectivity (RSFC) or increased connectivity between brain regions has also been shown in tinnitus using fNIRS. However, current fNIRS technology utilizes infrared (IR)-sources and IR-detectors placed on the scalp that restricts (~3 cm depth IR penetration) signal capture to outer cerebral cortex due to skin and skull bone. To overcome this limitation, in this proof of concept study, we adapted fNIRS probes to fit in the external auditory canal (EAC) to physically place IR-probes deeper within the skull thereby extracting neural signals from deeper auditory cortex. Methods: Twenty adults with tinnitus and 20 nontinnitus controls listened to periods of silence and broadband noise before and after 5 min of silence to calculate RSFC. Concurrent scalp probes over auditory cortex and an adapted probe placed in the right EAC were utilized. Results: For standard probes, left and right auditory cortex in tinnitus showed increased RSFC to each other and to other nonauditory cortices. Interestingly, adapted fNIRS probes showed trends toward increased RSFC. Conclusion: While many areas for the adapted probes did not reach significance, these data using a highly innovative and newly created probe adapting fNIRS technology to the EAC substantiates our previously published data in human tinnitus and concurrently validates this technology as a useful and expanded brain imaging modality.
Databáze:	MEDLINE
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