Age-related decline in cochlear ribbon synapses and its relation to different metrics of auditory-nerve activity
| Autor: | Sonny Bovee, Rainer Beutelmann, Christine Köppl, Lichun Zhang, Amarins N. Heeringa, Georg M. Klump, Friederike Steenken |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Aging
medicine.medical_specialty Hearing loss Nerve fiber Audiology Ribbon synapse Biology Synapse Age related otorhinolaryngologic diseases medicine Animals Hair Cells Auditory Inner Nerve activity Round window General Neuroscience Auditory Threshold Presbycusis Peripheral medicine.anatomical_structure Acoustic Stimulation Synapses sense organs Neurology (clinical) Geriatrics and Gerontology medicine.symptom Gerbillinae Developmental Biology |
| Zdroj: | Neurobiology of Aging. 108:133-145 |
| ISSN: | 0197-4580 |
| DOI: | 10.1016/j.neurobiolaging.2021.08.019 |
| Popis: | Loss of inner hair cell-auditory nerve fiber synapses is considered to be an important early stage of neural presbyacusis. Mass potentials, recorded at the cochlear round window, can be used to derive the neural index (NI), a sensitive measure for pharmacologically-induced synapse loss. Here, we investigate the applicability of the NI for measuring age-related auditory synapse loss in young-adult, middle-aged, and old Mongolian gerbils. Synapse loss, which was progressively evident in the 2 aged groups, correlated weakly with NI when measured at a fixed sound level of 60 dB SPL. However, the NI was confounded by decreases in single-unit firing rates at 60 dB SPL. NI at 30 dB above threshold, when firing rates were similar between age groups, did not correlate with synapse loss. Our results show that synapse loss is poorly reflected in the NI of aged gerbils, particularly if further peripheral pathologies are present. The NI may therefore not be a reliable clinical tool to assess synapse loss in aged humans with peripheral hearing loss. |
| Databáze: | OpenAIRE |
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