Research shows that a brain circuit reinforces motor speed control

Researchers at Karolinska have discovered how brain circuits encode the onset, duration, and abrupt change of motor speed. The study was published in neuron.

Movement—”moving around” in the form of walking, running, or swimming—is a common behavior that allows us to interact with the world around us. Precise control over the start and duration of a movement phase, combined with the ability to make rapid changes in strength and speed, are key features for the versatility of movement. For example, we can suddenly change our movement speed from slow to running to adapt to our surroundings.

“Using the zebrafish as a model systemOur previous work revealed that neurons in spinal cord responsible for carrying out the movement assembled in Process consists of three modules, which act as gearshift mechanisms to increase speed,” said Abdel El Manira, Professor in the Department of Neuroscience and corresponding author of the paper.

“An outstanding question that remains unresolved is how upstream circuits, which reside in the brain stem, encode and transmit motor initiation, duration, and rate changes to executive circuits. this in the spinal cord.”

important discovery

By exploiting the relative accessibility of adult zebrafish, combined with a range of techniques, researchers are now able to reveal two brain circuit encodes the onset, duration, and abrupt change in motor speed.

The brain circuits represent the first step in a sequence of commands that encode the initiation, duration, speed, and strength of movement. Two lines of command are revealed here, with direct access to spinal circuits, allowing animals to navigate in their environment by grading the speed and strength of their locomotor movements, while controlling direction. These mechanisms in adult zebrafish can be extrapolated to mammalian model systems.

Connect map

The next step would be to map the connection between these brain circuits and those in the spinal cord that promote movement.

It is hoped that the circuit revealed in the study can guide the design of new therapeutic strategies for recovery motor function after spinal cord injury.