English: Optical neural-firing manipulation techniques from left to right: ChR: blue light (480 nm) agitation of Channelrhodopsins (ChRs) leads to channel opening and Na⁺ influx. Sodium ion influx leads to depolarisation and evokes neural firing. HR: Halorhodopsins are activated by yellow light (570 nm). Open channels allow chloride ions to enter the cell, leading to hyperpolarisation and thus inhibition of action potential formation. Opto-XR: Animal-Rhodopsins (light-green) are the light sensitive part in the constructs. The intracellular loops (dark-green) are exchanged for signalling sequences of the targeted pathways. Opto-XR excitation leads to alteration in the signal transduction and thus influences the cells responses and metabolism. IR-irradiation: Cell irradiation with infrared laser-pulses locally induces thermal gradients and provokes neural firing.