Fig. 6

A semi-automatic perimeter approach is a reliable way of assessing changes in body length during and after optogenetic stimulation. A Schematic outline of image processing in Fiji to follow body length changes over time in a semi-automatic way. B Raw readings of body length (perimeter in pixels) of a worm expressing ChR2 in cholinergic neurons (unc-17p::ChR2::YFP) plotted against time in milliseconds, the graph represents n = 1. C The change in body lengths (normalized to length before illumination) of multiple worms, n = 10, when using a perimeter approach to estimate the worm length. ∆body length equals the change in length before illumination and during illumination. D Schematic of a worm with the midline and perimeter highlighted. E The relationship between the midline of the worm and the perimeter. n = 70 (35 still images of worms at light ON and 35 worms at light OFF). The spearman correlation was calculated (p < 0.001)