Type II spiral ganglion afferent neurons drive medial olivocochlear reflex suppression of the cochlear amplifier.

TitleType II spiral ganglion afferent neurons drive medial olivocochlear reflex suppression of the cochlear amplifier.
Publication TypeJournal Article
Year of Publication2015
AuteursFroud, KE, Wong, AChi Yan, Cederholm, JME, Klugmann, M, Sandow, SL, Julien, J-P, Ryan, AF, Housley, GD
JournalNat Commun
Volume6
Pagination7115
Date Published2015 May 12
ISSN2041-1723
KeywordsAnimals, Cochlea, Female, Gene Expression Regulation, Male, Mice, Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Neurons, Afferent, Peripherins, Reflex, Spiral Ganglion
Abstract

The dynamic adjustment of hearing sensitivity and frequency selectivity is mediated by the medial olivocochlear efferent reflex, which suppresses the gain of the 'cochlear amplifier' in each ear. Such efferent feedback is important for promoting discrimination of sounds in background noise, sound localization and protecting the cochleae from acoustic overstimulation. However, the sensory driver for the olivocochlear reflex is unknown. Here, we resolve this longstanding question using a mouse model null for the gene encoding the type III intermediate filament peripherin (Prph). Prph((-/-)) mice lacked type II spiral ganglion neuron innervation of the outer hair cells, whereas innervation of the inner hair cells by type I spiral ganglion neurons was normal. Compared with Prph((+/+)) controls, both contralateral and ipsilateral olivocochlear efferent-mediated suppression of the cochlear amplifier were absent in Prph((-/-)) mice, demonstrating that outer hair cells and their type II afferents constitute the sensory drive for the olivocochlear efferent reflex.

DOI10.1038/ncomms8115
Alternate JournalNat Commun
PubMed ID25965946
PubMed Central IDPMC4432632
Grant ListI01 BX001205 / BX / BLRD VA / United States
I01 RX000977 / RX / RRD VA / United States
R01 DC000139 / DC / NIDCD NIH HHS / United States
DC00139 / DC / NIDCD NIH HHS / United States