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Plastic changes along auditory pathway during salicylate-induced ototoxicity: Hyperactivity and CF shifts.
- Source :
-
Hearing research [Hear Res] 2017 Apr; Vol. 347, pp. 28-40. Date of Electronic Publication: 2016 Oct 27. - Publication Year :
- 2017
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Abstract
- High dose of salicylate, the active ingredient in aspirin, has long been known to induce transient hearing loss, tinnitus and hyperacusis making it a powerful experimental tool. These salicylate-induced perceptual disturbances are associated with a massive reduction in the neural output of the cochlea. Paradoxically, the diminished neural output of the cochlea is accompanied by a dramatic increase in sound-evoked activity in the auditory cortex (AC) and several other parts of the central nervous system. Exactly where the increase in neural activity begins and builds up along the central auditory pathway are not fully understood. To address this issue, we measured sound-evoked neural activity in the cochlea, cochlear nucleus (CN), inferior colliculus (IC), and AC before and after administering a high dose of sodium salicylate (SS, 300 mg/kg). The SS-treatment abolished low-level sound-evoked responses along the auditory pathway resulting in a 20-30 dB threshold shift. While the neural output of the cochlea was substantially reduced at high intensities, the neural responses in the CN were only slightly reduced; those in the IC were nearly normal or slightly enhanced while those in the AC considerably enhanced, indicative of a progress increase in central gain. The SS-induced increase in central response in the IC and AC was frequency-dependent with the greatest increase occurring in the mid-frequency range the putative pitch of SS-induced tinnitus. This frequency-dependent hyperactivity appeared to result from shifts in the frequency receptive fields (FRF) such that the response areas of many FRF shifted/expanded toward the mid-frequencies. Our results suggest that the SS-induced threshold shift originates in the cochlea. In contrast, enhanced central gain is not localized to one region, but progressively builds up at successively higher stage of the auditory pathway either through a loss of inhibition and/or increased excitation.<br /> (Copyright © 2016. Published by Elsevier B.V.)
- Subjects :
- Acoustic Stimulation
Adaptation, Physiological
Adaptation, Psychological
Animals
Auditory Cortex physiopathology
Auditory Fatigue
Cochlea physiopathology
Cochlear Nucleus physiopathology
Disease Models, Animal
Evoked Potentials, Auditory
Hearing Disorders chemically induced
Hearing Disorders prevention & control
Inferior Colliculi physiopathology
Male
Rats, Sprague-Dawley
Time Factors
Auditory Pathways physiopathology
Auditory Threshold
Behavior, Animal
Hearing
Hearing Disorders physiopathology
Hearing Disorders psychology
Neuronal Plasticity
Sodium Salicylate
Subjects
Details
- Language :
- English
- ISSN :
- 1878-5891
- Volume :
- 347
- Database :
- MEDLINE
- Journal :
- Hearing research
- Publication Type :
- Academic Journal
- Accession number :
- 27989950
- Full Text :
- https://doi.org/10.1016/j.heares.2016.10.021