Age-related decline in cochlear ribbon synapses and its relation to different metrics of auditory-nerve activity.

Autor: Steenken F; Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg Oldenburg, Germany., Heeringa AN; Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg Oldenburg, Germany., Beutelmann R; Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg Oldenburg, Germany., Zhang L; Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg Oldenburg, Germany., Bovee S; Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg Oldenburg, Germany., Klump GM; Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg Oldenburg, Germany., Köppl C; Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg Oldenburg, Germany. Electronic address: christine.koeppl@uni-oldenburg.de.
Jazyk: angličtina
Zdroj: Neurobiology of aging [Neurobiol Aging] 2021 Dec; Vol. 108, pp. 133-145. Date of Electronic Publication: 2021 Sep 04.
DOI: 10.1016/j.neurobiolaging.2021.08.019
Abstrakt: 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.
(Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: