Technion team unveils secrets of how the brain achieves skilled movement
They hope that the research will be able to help people who suffer from movement difficulties stemming from brain diseases in the future.
By DONNA RACHEL EDMUNDSAn image of the human brain(photo credit: REUTERS)
The ability to move is fundamental to all animals on the planet, allowing them to look for food, find a mate and change their environment to better be able to survive. But until now, scientists have very little understanding of how the brain learns to control the complex motor skills involved in making those movements that are so essential to every animal.Researchers at Technion have recently published a study in the journal Neuron which sought to address the question of whether nerve cells, known as neurons, register the reward, the movement, or both, and how neurons track whether a movement had a positive or negative task outcome, regardless of the actual reward or movement.They did this by giving mice a dexterity task - reaching and grasping for food - and monitoring what happened in the mouse's primary motor cortex, where motor plans are learned and controlled, using a range of techniques included imaging, genetic, behavioral and advanced computational tools.Through these techniques, the team discovered two separate neuron populations reporting successful or failed behavior attempts, which indicates that the brain registers an overall assessment of motor performance, rather than the specifics of a movement or its reward. They also discovered that neurons log the outcome, effecting the initial state activity of the neuron for the next time the movement is performed, and that the brain has to be active in this area in order for the movement to be more exact the next time around.Professor Jackie Schiller, who co-led the team, has suggested that the brain's method of recording whether a task was successfully completed or not, rather than whether the specific movement was carried out perfectly or not, may be a key reason why the primary motor cortex is essential for skilled movements.The team also discovered that different groups of neurons are responsible for assessing whether a task was successfully completed or not, and assessing the movement. They have theorized that splitting the functions in this way allows different plasticity rules to operate in different network, making the brain more responsive to learning.They hope that the research will be able to help people who suffer from movement difficulties stemming from brain diseases in the future."We would like to find out, for example, which brain pathways are involved in activating these cells and how these signals can be used, in combination with machine-brain interfaces, to improve movement in patients, such as those suffering from Parkinson's disease," said Prof. Schiller.
