Figure 1
(Top) Wikimedia Commons/Madhero88; (Bottom) Adapted from N. Sim et al. [1]

Figure 1: (Top) Structure of a rod cell in the retina. Photons absorbed in the outer segment cause a rearrangement of rhodopsin molecules, which initiates a sequence of chemical events resulting in excitation of an optic nerve signal. (Bottom) Microscope image of the fiber taper and a suction micropipette with the constrained rod cell. The cell response to photons is measured with the pipette, which acts as a micro electrode.