Cochlear hair cell innervation is dependent on a modulatory function of Semaphorin-3A.

Background: Proper connectivity between type I spiral ganglion neurons (SGNs) and inner hair cells (IHCs) in the cochlea is necessary for conveying sound information to the brain in mammals. Previous studies have shown that type I SGNs are heterogeneous in form, function and synaptic location on IHCs, but factors controlling their patterns of connectivity are not well understood.

Results: During development, cochlear supporting cells and SGNs express Semaphorin-3A (SEMA3A), a known axon guidance factor.