Schematic diagram of the experimental method.

<p>A single cilium (shown in red) from a frog ORN is sealed inside a glass micropipette (black). The base of the cilium, which is attached to the dendrite in vivo, is shown at the left. The distal tip is at the right. The base of the cilium is open and allows diffusion of Ca<sup>2+</sup> (light blue) from the surrounding bath into the cilium. As Ca<sup>2+</sup> reaches Cl<sup>−</sup> channels (green) in the ciliary membrane, it gates them, allowing an inward current (efflux of Cl<sup>−</sup>, dark blue arrows). The uniform distribution of channels shown does not represent the experimental finding. At the bottom are shown the approximate extents of the proximal (P) and distal (D) segments of the cilium as described by Reese <a href="" target="_blank">[11]</a>. Only the relative diameters and the relative lengths of the proximal and distal segments are drawn to scale. Reprinted from <a href="" target="_blank">[9]</a>, Flannery et al. (2006), copyright 2006, with permission from Elsevier.</p>