Effort experience as a driver of behavioral modulation in Caenorhabditis elegans
Effort is typically studied as a cost that influences choice, motivation, or persistence, but less is known about whether effort embedded within ordinary behavior can itself leave a trace that alters subsequent behavior. We developed a Caenorhabditis elegans paradigm in which animals reached the same food source under low or high effort conditions and were then tested in various behavioral contexts. Prior high effort enhanced subsequent food approach, generalized to more demanding tests including aversive barrier crossing, and persisted for at least 1 h but was lost by 24 h. The effect was distinct from food deprivation and was accompanied by context-dependent changes in locomotor dispersal rather than a uniform increase in activity. A monoamine screen implicated tyramine signaling. High effort also reduced ongoing activity in the tyraminergic RIM interneurons and enhanced the AWC OFF sensory response. These findings identify effort as a behaviorally consequential component of ordinary experience and suggest that ongoing behavior can generate internal state changes that may recursively influence future behavior.