From planning to action: Fundamental insights on movement planning in the brain

When a command is given, all participants in the experiment release their levers with swift precision, demonstrating that our brain initiates movement planning in advance. At the BrainLinks–BrainTools interdisciplinary center at the University of Freiburg, researchers have delved into the neural mechanisms that govern this process.

In a study published in the journal Cell Reports, they present an enhanced model for understanding the brain's role in movement planning. This research offers valuable insights into how the brain controls movement, which could lead to treatments for individuals with mobility challenges. To conduct the study, the team trained rats to move a lever with their hand, receiving a sugar reward upon completion.

The rats' brain activity was monitored throughout the process. The premotor and primary motor cortexes, two specific areas in both rats and humans, play crucial roles in movement planning and execution. While it was previously unclear how these areas coordinated, the researchers focused on this aspect and discovered that neurons in the premotor cortex communicate with both inhibitory and excitatory neurons in the primary motor cortex.

The execution of a movement only occurs when the premotor cortex shifts towards neurons mainly connected to excitatory targets in the motor cortex. This shifting pattern of neural activity, dubbed the switching population hypothesis, replaces previous dominant theories. By integrating light manipulation, artificial intelligence, and anatomical evidence, the research team has provided a comprehensive understanding of how the brain orchestrates movement.