Fly nerve cells that sense limb movement are turned off during active motion, study shows

In a fruit fly, the nerve cells that detect the movement of the limbs are silenced when the insect works or the toilet. This on-off switch can help the nervous system to move between two states: an aid to keep the body stable and the other prepares it to move.

The neuroscientist of the UW Medicine, John Tuthill, explained the difference by a human analogy: “Stabilizing reflexes allow us, for example, to remain straight on an influencing train, while active mode supports dynamic movements like walking on unequal ground.”

“All animals have a sense of position and movement of their body, known as proprioception, which is used to stabilize their body posture and guide their movements,” he said.

Tuthill is a professor of neurobiology and biophysics at the University of Washington Medicine School. Its laboratory studies the cells, signals and circuits that govern proprioception and engine control in flies.

Directed by its former postdoctoral Chris Dallmann, research leading to the new conclusions was reported on September 17 Nature.

Researchers have shown that proprioceptive nerve cells to detect leg movement are disabled during active movement. They also discovered the neural circuit which gives birth to this switch dependent on the state, which the brain uses to switch between the maintenance of postural reflexes and the maintenance of a voluntary movement.

The capacity of the fly to selectively delete the comments of the movement, supposed the researchers, could make the insect more sensitive to the sudden external events which would disrupt it, and therefore faster to respond.

The progression of basic scientific knowledge of sensory comments which is flexibly adjusted to manage these double tasks could lay the foundations for future clinical applications.

“Understanding how proprioception is used to control the body is important to develop treatments for sensorimotor disorders and support rehabilitation after an injury,” said Tuthill.

When carrying out this recent fruit flies study, the Tuthill laboratory used specific calcium imagery of the cellular type to learn that projections of nerve cells detecting the position work through a range of behaviors. The inhibition of the feedback of movements during walking and grooming occurred via a specific class of nerve cells – Internet – which work as a link between sensory neurons and motor neurons.

This selective abolition only took place during active and self-directed movements by the insect, not the passive movements of the insect members. The researchers have drawn the nerve signaling pathways that lead this inhibition in a specific way to the leg.

Researchers have indicated that some results suggest that inhibition can be carried out predictive when the leg is still at rest, after the interneurons receive signals from the brain and before the start of the movement. Dallmann continues his research on how neural circuits control the movement as a Marie Sklodowska-Curie scholarship holder at Wuerzburg University, Germany.