Comparison of automated thrashing assay with manual measurements. (A) The performance of the machine method on C. elegans is compared with that of two human observers. The variance in the automated system's performance can therefore be compared with the difference in performance between two trained observers. Each point represents the mean of counts for 8 worms, in accordance with the customary thrashing assay. (B) Comparison of results for individual C. elegans with mutations in nicotinic acetylcholine receptors with ranges of motilities. (C) Although the machine frequently underestimates the counts because of outliers, the effect of these outliers in each batch of 8 worms is reduced when the medians for each method are plotted. (D) A comparison of automated and manual thrashing assays on C. elegans or the parasitic nematode, Haemonchus contortus, in the presence of two concentrations of levamisole. Despite the challenges presented by H. contortus, the automated assay produces similar results to manual measurements.