Figure 1. Controlling the C. elegans neural network.

(a) Schematic neural circuit for locomotor response to gentle touch in C. elegans (adapted after Ref. 30; see SI Sec. III A). (b) Graphical representation of the proposed control framework. According to the principles illustrated in Fig. 2(a-d), if removal of a neuron disrupts controllability of the muscles, we designate it “essential” for locomotion; if not, we call it “non-essential”. To make this assessment, we first mapped the C. elegans responsive locomotor behaviours into a target network control problem, asking to what degree the sensory neurons (blue) can control the muscles (pink). This allowed us to predict the previously-unknown involvement of PDB in C.elegans locomotion, and functional differences between individual neurons within the DD neuronal class. (c) The C. elegans connectome used in our study, consisting of 279 neurons (the 282 nonpharyngeal neurons, excluding CANL/R and VC06 which do not make connections with the rest of the network) and 95 muscles. Node size is proportional to the sum of its in- and out- degrees. Filled nodes represent the neurons traditionally assigned to the circuits responsible for gentle touch response, hinting at the complexity of predicting neuronal function from the wiring diagram alone.