Fig. 4

Figure 4. Input into ipsilateral Mauthner cell biases escapes

(A) Two-photon image of both Mauthner cells (upper panel) in our custom Gal4 line. Left: Mauthner cell pre-ablation showing our laser targeting protocol for Mauthner destruction. Same cell post ablation.

(B) PI for escapes away from intact Mauthner in control and barrier conditions (p = 0.01988) (N = 26, n = 275 control, 192 barrier). Error bars are 95% CI of the median.

(C) Individual escape directions for animals with the left Mauthner cell ablated. Fish with an ablated left Mauthner cell show escape bias to the left (left). Escapes in left Mauthner ablated fish with barrier on the right show an increased bias to the left away from the barrier (center), whereas a barrier on the left leads to continued biased escape to the left (toward the barrier). This result suggests that there is no inhibitory mechanism on the intact Mauthner that prevents escapes toward barriers (compare E).

(D) Barrier avoidance index and collision rates for fish with Mauthner cell ablations. Fish no longer avoid barriers if the Mauthner cell on the side of the barrier is ablated; ablations reveal that there is no inhibitory mechanism onto the intact Mauthner that prevents collisions with barriers (i.e., the intact Mauthner continues to pull the fish toward barriers. p = 1.6e−5 and 2.8e−5. Medians are indicated in red and boxes indicate the interquartile range.

(E) Proposed model after integration of Mauthner cell ablation experiments reveals excitatory/disinhibitory input into ipsilateral Mauthner cell, which favors escapes away from barriers. See also Figure S4.