Residual Inhibition Functions Overlap Tinnitus Spectra and the Region of Auditory Threshold Shift
- 20 August 2008
- journal article
- research article
- Published by Springer Science and Business Media LLC in Journal of the Association for Research in Otolaryngology
- Vol. 9 (4), 417-435
- https://doi.org/10.1007/s10162-008-0136-9
Abstract
Animals exposed to noise trauma show augmented synchronous neural activity in tonotopically reorganized primary auditory cortex consequent on hearing loss. Diminished intracortical inhibition in the reorganized region appears to enable synchronous network activity that develops when deafferented neurons begin to respond to input via their lateral connections. In humans with tinnitus accompanied by hearing loss, this process may generate a phantom sound that is perceived in accordance with the location of the affected neurons in the cortical place map. The neural synchrony hypothesis predicts that tinnitus spectra, and heretofore unmeasured “residual inhibition functions” that relate residual tinnitus suppression to the center frequency of masking sounds, should cover the region of hearing loss in the audiogram. We confirmed these predictions in two independent cohorts totaling 90 tinnitus subjects, using computer-based tools designed to assess the psychoacoustic properties of tinnitus. Tinnitus spectra and residual inhibition functions for depth and duration increased with the amount of threshold shift over the region of hearing impairment. Residual inhibition depth was shallower when the masking sounds that were used to induce residual inhibition showed decreased correspondence with the frequency spectrum and bandwidth of the tinnitus. These findings suggest that tinnitus and its suppression in residual inhibition depend on processes that span the region of hearing impairment and not on mechanisms that enhance cortical representations for sound frequencies at the audiometric edge. Hearing thresholds measured in age-matched control subjects without tinnitus implicated hearing loss as a factor in tinnitus, although elevated thresholds alone were not sufficient to cause tinnitus.Keywords
This publication has 39 references indexed in Scilit:
- Homeostatic signaling: the positive side of negative feedbackCurrent Opinion in Neurobiology, 2007
- Frequency organization of the 40-Hz auditory steady-state response in normal hearing and in tinnitusNeuroImage, 2006
- Residual inhibition functions in relation to tinnitus spectra and auditory threshold shiftActa Oto-Laryngologica, 2006
- Age-Related Changes in the Inhibitory Response Properties of Dorsal Cochlear Nucleus Output Neurons: Role of Inhibitory InputsJournal of Neuroscience, 2005
- The neuroscience of tinnitusTrends in Neurosciences, 2004
- Effect of unilateral partial cochlear lesions in adult cats on the representation of lesioned and unlesioned cochleas in primary auditory cortexJournal of Comparative Neurology, 1993
- Tuning curves and pitch matches in a listener with a unilateral, low-frequency hearing lossThe Journal of the Acoustical Society of America, 1983
- Parametric Studies of Tinnitus Masking and Residual InhibitionBritish Journal of Audiology, 1983
- The Masking of Tinnitus with Pure TonesInternational Journal of Audiology, 1983
- Homolateral and Contralateral Masking of Tinnitus by Noise-Bands and by Pure TonesInternational Journal of Audiology, 1971