Modelling temperature rise and spatial resolution in optogenetic stimulation by two-photon excitation fluorescence transfer

Modelling temperature rise and spatial resolution in optogenetic stimulation by two-photon excitation fluorescence transfer

The combination of optogenetics and two-photon excitation causes neurons in the brain to be stimulated with a high temporal precision of about milliseconds and a high spatial precision of about micrometers. One of the most efficient and new methods in two-photon optogenetics is the use of fluorescent proteins with a high two-photon cross-section in the vicinity of opsin. In this paper, the amount of temperature increase in optogenetic stimulation by the two-photon excitation fluorescence transfer method is modeled, as well as its spatial resolution. The simulation results show that after 0.3 seconds of irradiation with a laser power of 4.7 mW, the temperature rises by 0.35 K, and after 20 seconds of irradiation with a laser power of 8.6 mW, the temperature rises by 0.79 K. Furthermore, the intensity of the light emitted by the target cell to the adjacent nerve cell at a distance of 25 micrometers will decrease by 98%, which indicates the high spatial resolution in this technique.