Figure 2
Synaptic locations were transformed to a hair-cell-based coordinate system. (a) Schematic shows the synapses of three auditory-nerve terminals (light gray, green, and red) around the basolateral surface of an IHC (blue). (b) A zy maximum projection of the image stack shown in (d) superimposes 12 adjacent IHCs from the 16-kHz region of a control ear. Arrowhead points to an orphan ribbon, i.e. one that is unpaired with a GluA2-positive punctum. The cyan, dashed shape superimposed on panels in (b,c,e) is an outline of the Myo7a-staining from the zy projection in panel (b). (c) To quantify ribbon sizes and positions across z stacks, we transformed the zy plane as schematized, placing a new vertical axis parallel to the IHCs’ long axis and bisecting the IHCs’ basolateral pole into pillar- and modiolar-facing halves. Axis values in c are in microns, and the image is the same as in (b), except the GluA2 channel is masked. (e) A maximum projection of each IHC in (d) is extracted from the z-stack and shown in the zy projection. Axes are the same as in (c).
