Fig. 2.

AWB and command interneurons are necessary and sufficient for reflexive aversion. A Diagram of light-inducible ablation of neurons without damage to surrounding tissue via a mini singlet oxygen generator (miniSOG), a genetically encoded photosensitizer. L2 wild-type larvae and larvae expressing miniSOG in specific neurons were exposed to continuous blue-light stimulation for 2 h, allowed to reach adulthood, and then tested for reflexive aversion to P. aeruginosa both before and after training. B Response index to P. aeruginosa for both naïve (gray) and trained (green) animals with either no neurons ablated (N2, WT) or AVA/AVD/AVE neurons ablated (ZM7054). C Diagram of stimulation of neurons expressing the blue-light-activated cation channel channelrhodopsin-2 (ChR2). Animals were grown to L4 larvae and then transferred to plates with E. coli OP50 supplemented with all-trans retinal (ATR). Plates without ATR were used as a control. Animals were allowed to feed overnight for 16 h, and then placed under an epifluorescent microscope fitted with an EGFP filter. Forward crawling animals were stimulated with one second of blue light, and a response recorded if an animal moved backwards during the stimulation. D Response index to blue-light stimulation for animals expressing ChR2 in AWB or AVA neurons with no ATR supplementation (gray) and with ATR supplementation (blue). For both B and D, two-way ANOVA with a subsequent comparison between groups was performed. Error bars depict standard deviation. N = 25 (individual dots) for all groups