Itskovits, Eyal et al. (2015) International Worm Meeting "A new multi-worm tracker reveals unprecedented insights on worm chemotaxis."

Itskovits, Eyal, Zaslaver, Alon

[International Worm Meeting, 2015]

We have developed a novel Multi Worm Tracker (MWT) that is capable of tracking over a hundred worms simultaneously. The tracker employs a machine learning classification approach to identify the behaving worms. The system produces a long informative track for each individual worm, and generally maintains tracking despite frequent animal collision events. This MWT provides unprecedented statistical power revealing subtle, yet significant, behavioral features. Here we present results that challenge the prevalent "biased random walk" strategy of worms' chemotaxis. Moreover, we readily obtain data with satisfactory statistical significance following a single chemotaxis assay. Our system includes a suite of solutions for acquisition, tracking, and statistical analyses via a friendly user interface that is easy to operate with minimal programming skills.

Ruach, Rotem et al. (2019) International Worm Meeting "Irrational behavior in C. elegans arises due to asymmetric modulatory effects between options."

Eyal, Itskovits, Iwanir, Shachar, Ruach, Rotem, Pritz, Christian, Bokman, Eduard, Zaslaver, Alon

[International Worm Meeting, 2019]

Animals, like humans, repeatedly violate rational-choice paradigms, yet the underlying reasons remain debatable. This is primarily because population variability, past experience, current state, and future expectations affect decision-making cognitive processes, thus precluding decisive conclusions. Here, we established C. elegans nematodes as a powerful model for studying rationality of an innate behavior - chemotaxis, thus overcoming many of the above confounding effects. Moreover, innate behaviors presumably evolved to comply with rational economic axioms to maximize fitness. Surprisingly, we found that worms' chemotaxis behavior robustly violates key rationality paradigms of transitivity, independence of irrelevant alternatives and regularity. These violations arise due to asymmetric modulatory effects between the presented options. Functional analysis of the entire chemosensory system at a single-neuron resolution, coupled with analyses of mutants, defective in individual neurons, reveals that these asymmetric effects originate in specific sensory neurons. Thus, asymmetric modulations between options' representations may provide a simple explanation for irrational behavior.