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Monoaminergic Orchestration of Motor Programs in a Complex C. elegans Behavior

Figure 4

Ablation of VD or DD motor neurons induces a navigational bias.

(A) Schematic of D-motor neuron wiring. VD motor neurons receive inputs from cholinergic DB motor neurons, and release GABA on ventral body wall muscles. DD motor neurons receive input from cholinergic VB motor neurons and release GABA on dorsal body wall muscles. Figure adapted from (B, C) Killing subsets of GABAergic motor neurons by laser ablation-induced navigational biases. (B) Turning rate (°/sec ± SEM) is affected in animals where VD or DD neurons are ablated. DD-ablated animals navigate with a dorsal bias. VD-ablated animals navigate with a ventral bias. Mock-ablated animals, GABA-deficient mutants (unc-25), and ser-2 mutants did not show a change in turning rate. Turning angle was calculated by worm tracking software; n is indicated. (C) Representative locomotory path of a DD-ablated (left panel) and VD-ablated animal (right panel). DD-ablated animals locomote in dorsally directed circles (Movie S1). VD-ablated animals locomote in ventrally directed circles (Movie S2). The direction of locomotion (°) was determined from orientation of the animal's trajectory on the plate (inset). Red line traces the path of locomotion from the origin (black dot); yellow arrow designates the ventral side of the animal. Instantaneous turning angle is plotted for the duration of the locomotion path. Statistical differences calculated from mock ablations: *p<0.05, ***p<0.001, two-tailed Student's t test.

Figure 4