IHC synapses in confocal z-stacks, acquired in the x-y plane (A) and
re-projected into the y-z (B) plane. A Pre- and
post-synaptic elements in the IHC area are counted in cochlear whole mounts
quadruple-immunostained for CtBP2 (red), GluA2 (green), NaK ATPase (blue), and
myosin VIIa (white). B Size gradients in pre- and post-synaptic
elements are quantified according to location along habenular-cuticular and
modiolar-pillar axes (Liberman et al.,
2015). (C) Tracing of peripheral axons from a cross
section through the osseous spiral lamina (OSL; D) in a normal cat
shows the SR-based gradient from thin (low-SR) to thick (high-SR) fibers (Kawase and Liberman, 1992).