A new study has shed light on the HSN neuron in the C. elegans worm and its ability to control various behaviors. The research, conducted by scientists from MIT, highlights the versatility of the neuron in managing activities such as egg-laying and locomotion.

The HSN neuron releases multiple chemicals that guide different behaviors, including egg-laying and subsequent deceleration. One key finding of the study is that neurons can “borrow” serotonin from others to influence behavior. This idea could have implications for understanding the role of serotonin in mental health conditions.

The researchers conducted a series of experiments to uncover how the HSN neuron controls these behaviors. Using optogenetics, they manipulated the neuron’s activity and confirmed its role in egg-laying, acceleration, and deceleration. They also tracked the neuron’s electrical activity and identified specific patterns associated with egg-laying and locomotion.

Furthermore, the study revealed that the HSN neuron releases neurotransmitter chemicals such as serotonin, acetylcholine, and neuropeptides to control behavior. By eliminating specific neurotransmitters, the researchers were able to determine their role in different behaviors. For example, serotonin was found to be crucial in decelerating the worm after egg-laying.

Anatomy also played a role in behavior control. It was discovered that the HSN neuron’s axon, which carries signals to other neurons, coordinates egg-laying and locomotion. By cutting the axon, the researchers disrupted this coordination and prevented the worm from performing both behaviors simultaneously.

Overall, the study highlights how the HSN neuron utilizes multiple neurotransmitter systems, cellular morphology, and unconventional transmission methods to control the behavior of the C. elegans worm. These findings not only expand our understanding of individual neuron function but also demonstrate the ability of neurons to influence a variety of behaviors on different timescales.