Figure 7. A reduced model explains the role of corollary discharge in sustaining forward locomotion during thermotaxis.

(A) Schematic of the circuit model. (B) Dynamics of the model in response to an oscillating input stimulus. Top: temporal profile of the input signal. Middle: dynamics of the model with the feedback strength set to 1 (positive feedback), 0 (no feedback), or −1 (negative feedback). (C) Simulated trajectories of navigational behavior on a 2-D arena with linear input gradient, with feedback strength set to 1 (left), 0 (middle), and −1 (right). (D) Thermotactic biases for trajectories generated by models with feedback strength equaling 1 (positive feedback), 0 (no feedback), or −1 (negative feedback). (E) Forward run duration as a function of forward run direction for the behavioral simulations in (D). (F) Fraction of cooling epochs that were followed by the termination of forward runs in simulations with the feedback gain set to 1 (blue) or 0 (black). (G) Fraction of forward runs that ended after a period of cooling in simulations with the feedback gain set to 1 (blue) or 0 (black). Error bars are 95% CI. Wilcoxon rank-sum test *p<0.05; **p<0.01; ***p<0.001.