Thermogenetic activation of 5-HT neurons does not affect locomotor abilities. A, Electric shock avoidance (left panel, n = 10 or 11) and forced flight (right panel, n = 5) are unaffected in flies expressing dTRPA1-mCherry under control of Trh-Gal4, both at 22°C and 32°C, compared with the heterozygous parental strains. B, In flies expressing dTRPA1-mCherry in motor neurons under control of D42-Gal4, thermogenetic neuronal activation impairs electric shock avoidance (left panel, n = 10 or 11) and forced flight (right panel, n = 5) at the effective temperature of 32°C, but not at 22°C. C, Negative geotaxis behavior assayed by countercurrent distribution at 18°C (left) and 32°C (right) in flies expressing dTRPA1-mCherry under control of Trh-Gal4 compared with the heterozygous parental strains. At 18°C, no difference between the strains is observed. At 32°C, negative geotaxis is attenuated, but not abolished, in flies expressing dTRPA1-mCherry under control of Trh-Gal4 (n = 5). D, Negative geotaxis behavior of flies expressing dTRPA1-mCherry under control of D42-Gal4 is indistinguishable from the heterozygous parental lines at 18°C (left). At 32°C (right), negative geotaxis is completely abolished in flies expressing dTRPA1-mCherry under control of D42-Gal4 (n = 5). Data points and bars indicate mean ± SEM. n.s., Not significant (p > 0.05). *p < 0.05. ***p < 0.001.