An optical stimulation system includes a control module coupleable to a lead having a light emitter and a sensing electrode. The light emitter emits light having one or more wavelengths that activate light-sensitive neurons within a target stimulation location. The light-sensitive neurons generate either an excitatory response or an inhibitory response when activated depending on the wavelength of the emitted light. The sensing electrode senses electrical activity from the activated light-sensitive neurons concurrently with emission of the light from the light emitter. The control module directs emission of light from the light emitter using stimulation parameters. The control module includes a closed-loop feedback subsystem for adjusting at least one of the stimulation parameters based, at least in part, on electrical activity of the activated light-sensitive neurons sensed by the sensing electrode.
