(a) Fluorescence of AFD soma in a nanoparticle-immobilized Pgcy-8::YC3.60 worm. Centroid of cell body indicated by crosshairs. Scale bar: 20 µm. (b) NP: Mean absolute displacement of AFD neuron cell body during 10 s intervals in animals immobilized with 0.1 µm diameter nanoparticles, as a function of agarose concentration in pad. NGM: no beads. (c) Mean absolute displacement of buccal cavity during 10 s intervals for adult worms on 10% agarose pads and varied bead diameters; L1, L3, and adult (Ad) worms immobilized with 0.1 µm beads on 10% agarose pads.