Does the brain control muscles or movements?
One of the major scientific questions about the brain is how it can translate the simple intent to perform an action—say, reach for a glass—into the dynamic, coordinated symphony of muscle movements required for that action. The neural instructions for such actions originate in the brain’s primary motor cortex, and the puzzle has been whether the neurons in this region encode the details of individual muscle activities or the high-level commands that govern kinetics—the direction and velocity of desired movements. Now, Robert Ajemian and his colleagues, analyzing muscle function in monkeys, have created a mathematical model that captures the control characteristics of the motor cortex. It enabled the researchers to better sort out the “muscles-or-movement” question. The researchers described their model in an article in the May 8, 2008, issue of the journal Neuron, published by Cell Press. Researchers have been thwarted in their efforts to measure and model the neural control of comple
