Optogenetic signal processing is described for an auditory prosthesis with an intracochlear array of optical stimulation sources implanted in a patient having auditory neurons genetically modified with light sensitive ion channels. Stimulation timing signals are generated for the corresponding auditory neurons for each band pass signal based on characteristic temporal fine structure features of the band pass signals. The stimulation timing signals include: i. one or more channel opening signals adapted to open the ion channels of the corresponding auditory neurons, and ii. one or more channel closing signals adapted to close the ion channels of the corresponding ion channels. Optical stimulation signals are then produced for the optical stimulation sources based on the stimulation timing signals.