Figure 2. Early data showing that channelrhodopsin-2 could mediate light-driven spiking in neurons.

Raw voltage trace recorded from a current-clamped neuron in vitro, expressing channelrhodopsin-2 and exhibiting light-activated spikes, here driven by four 15 ms-duration blue light pulses. The data here shown were acquired from the first channelrhodopsin-2-expressing neuron recorded in the study that culminated in [26].