eLife: A simple animal model reveals how environments and states combine to control behavior

Let's say you live opposite a

All animals face the challenge of weighing various sensory cues and internal states when formulating behaviors, but scientists know very little

"In this study, we dissected the mechanisms that control the level of individual olfactory receptors in individual olfactory neurons based on the constant state and stimulus experienced by the animals," said senior author Steven Flavell, an associate professor at

The study, led by MIT postdoc Ian McLachlan, was published on Aug.

"We were surprised to learn that an animal's internal state can have such a big impact on gene expression at the sensory neuron level — essentially, hunger and stress change the way

In fact, McLachlan, Flavell, and their team didn't specifically look for neurons AWA or specific olfactory chemical receptors, known as tr-44

This result alone suggests that the internal state (starvation) affects the degree of receptor expression of sensory neurons

For example, in an experiment by McLachlan and Flavell's team, when both fed and hungry worms squirmed to a strong enough smell that the receptors liked, only fasting worms (expressing more receptors) could detect weaker concentrations

Other experiments have shown how multiple factors push and pull STR-44

Several other experiments have investigated pathways in the roundworm nervous system that transmit sensory, hunger, and positive feeding signals to the AWA

Flavell and McLachlan note that pathways such as insulin and TORC2 are found not only in sensory neurons in other worms, but also in many other animals, including humans

McLachlan added that the study's fundamental insights could help investigate how gut-brain signaling through TORC2 works

"This is becoming the main pathway for gut-to-brain signaling caenorhabditis elegans, and I hope it will eventually have translational importance for human health," McLachlan said

In addition to McLachlan, Flavell, Kramer, and Dua, other authors of the paper include Matthew Gomes and Ugur Dag of MIT and Elizabeth DiLoreto and Jagan Srinivasan

essay

Diverse states and stimuli tune olfactory receptor expression levels to modulate food-seeking behavior