Figure 3.

Thermoreceptive regions/neurons in C. elegans. (a) The schematic drawing shows an adult animal with the anterior/tip of the nose to the left and the posterior/tail to the right. Somata of neurons are darkly shaded. The solid areas are the somata and axonal processes of AFD, AIY, and AIZ neurons that mediate thermotaxis response (34). The table below the drawing shows the percentage of wild-type (wt) and vab-3(e648) animals that responded to the heat stimulus in the indicated body region. The size of the laser is indicated to the left. (b) Neural circuit for thermotaxis (modified after ref. 34) showing the connectivity of AFD, AIY, and AIZ. Both ablation of the sensory neuron AFD or the interneuron AIY and mutations eliminating their functions lead to a cryophilic phenotype, whereas ablation or mutations abolishing the function of AIZ lead to a thermophilic phenotype (34). Neither mutant affected the thermal avoidance response.