Fig. 2: Induction of action potentials.

a Electrical stimulation that affects all cell types vs. optical stimulation via genetic targeting of (channelrhodopsin (ChR2) or halorhodopsin (NpHR))-optogenetic-constructs which is a cell-specific neuromodulation. b Optogenetic tool families^47,144 allowing induction of action potentials, silencing of neurons, or modulation of intracellular signaling cascades (Panel reprinted with permission from ref. ³⁴). c Classification of opsin genes (Reprinted (adapted) with permission from ref. ⁴⁸), and d Using minimally invasive NIR light (780 nm) and gold nanorods (AuNRs) to activate channel thermo-TRPs (photoactivation of TRPV1-overexpressing HEK293T cells). Schematic representation of the localized photothermal heating of a TRPV1-expressing plasma membrane bearing plasma membrane-targeted gold nanorods (pm-AuNRs) (Reprinted with permission from ref. ⁴).