Document Type

Article

Publication Date

9-27-2021

Publication Title

Front Neurosci

Keywords

JMG

JAX Source

Front Neurosci 2021 Sep 27; 15:695914

Volume

15

First Page

695914

Last Page

695914

ISSN

1662-4548

PMID

34646115

DOI

https://doi.org/10.3389/fnins.2021.695914

Grant

DC015242, DC018304

Abstract

Sensory hair cells detect mechanical stimuli with their hair bundle, an asymmetrical brush of actin-based membrane protrusions, or stereocilia. At the single cell level, stereocilia are organized in rows of graded heights that confer the hair bundle with intrinsic directional sensitivity. At the organ level, each hair cell is precisely oriented so that its intrinsic directional sensitivity matches the direction of mechanical stimuli reaching the sensory epithelium. Coordinated orientation among neighboring hair cells usually ensures the delivery of a coherent local group response. Accordingly, hair cell orientation is locally uniform in the auditory and vestibular cristae epithelia in birds and mammals. However, an exception to this rule is found in the vestibular macular organs, and in fish lateral line neuromasts, where two hair cell populations show opposing orientations. This mirror-image hair cell organization confers bidirectional sensitivity at the organ level. Here I review our current understanding of the molecular machinery that produces mirror-image organization through a regional reversal of hair cell orientation. Interestingly, recent evidence suggests that auditory hair cells adopt their normal uniform orientation through a global reversal mechanism similar to the one at work regionally in macular and neuromast organs. Macular and auditory organs thus appear to be patterned more similarly than previously appreciated during inner ear development.

Comments

I am very grateful to Elli Hartig and Dayana Krawchuk for their comments on the manuscript and editing advice.

This is an open-access article distributed under the terms of the Creative Commons Attribution License

Download

Share

COinS