Optogenetics in neurobiology

Optogenetics refers to the ability to control or monitor cellular activities with light (‘opto’) using genetically encoded machinery. In the case of channelrhodopsins (ChR): When expressed in neuronal cells, the application of light can stimulate cations into the cell, thus depolarising it, and stimulating action potentials. Conversely: proton and chloride-pumping rhodopsins can be used to selectively hyperpolarize the cell and inhibit action potentials through either pumping protons out or pumping chloride into the cell.