“…Remarkably, we are already able to record from the majority of the neurons, at cellular resolution, in two animals during free behavior, C. elegans [67,68] and another invertebrate, Hydra [69], though progress is being made toward similar capabilities in adult Drosophila [70,71], larval Drosophila [72], and larval zebrafish [73]. For C. elegans , real-time quantification of movement drives the motion of a motorized stage that re-positions the worm directly under the neural imaging scope [67,68].…”