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. Author manuscript; available in PMC: 2015 Nov 6.
Published in final edited form as: Cell. 2014 Nov 6;159(4):751–765. doi: 10.1016/j.cell.2014.09.056

Figure 4. AIY regulates locomotion speed by forming an excitatory circuit with its downstream neuron RIB.

Figure 4

(A–B) Laser ablation shows that RIB is required for AIY to promote locomotion speed. Worms expressing ChR2 as a transgene in AIY were assayed for locomotion speed in response to blue light. (A) Speed traces. no TG: non-transgenic siblings. (B) Bar graph. n ≥16. **p<0.0001 (ANOVA with Tukey’s HSD test).

(C) Double and single ablations of AIY and RIB yield a similar phenotype in locomotion speed. n ≥6. **p<0.0001 (ANOVA with Tukey’s HSD test).

(D–E) Optogenetic stimulation of RIB promotes locomotion speed. ChR2 was expressed as a transgene specifically in RIB. Control: non-transgenic siblings. (D) Speed traces. (E) Bar graph. n ≥12. **p<0.0001 (t test).

(F–G) Optogenetic inhibition of RIB suppresses locomotion speed. NpHR was expressed as a transgene specifically in RIB. (F) Speed traces. (G) Bar graph. n ≥22. **p<0.0001 (t test).

(H) Optogenetic manipulation of RIB activity does not trigger reversals. Neither stimulation of RIB by ChR2 nor inhibition of RIB by NpHR triggered reversals. The value for RIB::ChR2 is zero under this condition. n=5. **p<0.02 (t test).

(I) Calcium and locomotion velocity traces acquired with the CARIBN system. The windows highlighted in green denote reversals.

(J–K) Cross-correlation analysis shows that RIB calcium activity exhibits a strong correlation with forward locomotion speed (J) but not with backward locomotion speed (K). n=5.

(L–M) Stimulation of AIY promotes the activity of RIB. Worms carrying two transgenes (one expressing ChR2 in AIY and the other expressing RCaMP in RIB) were imaged with the CARIBN system. Control: worms carrying the RIB::RCaMP transgene only. (L) RIB RCaMP calcium traces. (M) Bar graph. n ≥17. **p<0.0001 (t test)

(N–O) Inhibition of AIY suppresses the activity of RIB. Worms carrying two transgenes (one expressing NpHR in AIY and the other expressing GCaMP3.0 in RIB) were imaged with the CARIBN system. Control: worms carrying the RIB::GCaMP3.0 transgene only. (N) RIB GCaMP3.0 calcium traces. (O) Bar graph. n ≥10. **p<0.0001 (t test)

(P) Schematic model showing that AIY forms an excitatory circuit with RIB to regulate locomotion speed.

All error bars: SEM.

Also see Figure S3.