. A, Full time-course of temperature changes measured using an acutely inserted thermocouple probe in dorsal striatum in response to light delivery at 3 mW or 15 mW (N = 1 mouse). Data reproduced from Fig. 2b. B, Time-course of opsin-independent decrease in MSN firing. Data reproduced from Fig. 1c in response to 532 nm light at 15 mW with time-scale adjusted to highlight contrast with optogenetic manipulation in Panel C. C, Optogenetic silencing of FSIs (green) and disinhibition of neighboring MSNs (blue) occurs on a time-scale much shorter than light-driven temperature changes recorded in Panel B (N=5 PV-2A-cre mice; n=64 MSNs, n=16 FSIs). D, Computer model simulations highlight the sensitivity of temperature changes to light pulse duration. Each trace represents equivalent light delivery (3 sec light over a 30 sec period = 10% duty cycle). Condensing this light into fewer pulses of longer duration each drives increased fluctuations in temperature. Simulation measured at 1 mm from the tip of a 200 μm optical fiber tip using 532 nm light at 15 mW. E, Computer model of predicted temperature changes in response to 1 sec at 15 mW light delivered with commonly used wavelengths. Simulation measured 1 mm from the tip of a 200 μm optical fiber. F. Computer model of predicted temperature change in response to 20 min illumination with 473 nm light through a 200 μm NA 0.39 fiber, 200um below fiber tip. Shaded regions indicated mean +/- s.e.m.