Fig. 5.

Synapse distribution in striolar regions of control and microgravity utricles. A and B: maximum-intensity projection micrographs representing confocal stacks from middle striolar regions in immunolabeled control (A) and microgravity utricles (B). Closely apposed CtBP2- and Shank1a-positive puncta (examples highlighted by white arrowheads) are observed throughout the micrographs. Synapses are clearly less dense in these striolar micrographs compared with those from medial extrastriola (Fig. 4). C: box-and-whisker plots of synapse densities (synapse count per 100 µm²) in caudal, middle, and rostral (Fig. 2A) striolar regions of control and microgravity specimens. Synapse densities in the striola were similar among all specimens regardless of gravitational condition. D: hair cell densities (hair cell count per 100 µm²) among the 3 striolar regions in control and microgravity specimens are illustrated in box-and-whisker plots. Hair cell densities across gravitational condition were similar.