Figure 4.

A, Afferent synapses on inner hair cells show opposing spatial gradients in size of the presynaptic and postsynaptic elements: in the xy projection, synapses with the largest ribbons and smallest AMPAR patches are farthest from the OHCs (filled arrows), while those closer to the OHCs (open arrows) tend to have large AMPAR patches and small ribbons. B, In the yz projection, the largest ribbons are on the modiolar side and basal pole of the hair cell, while the largest GluR2/3 patches are on the pillar side: the approximate outline of the IHCs is shown by dotted white lines. This confocal z-stack is through the synaptic regions of four adjacent IHCs from the 14 kHz region. See text for explanation of the yellow lines in B.