Researchers are redefining how the brain plans movement
By By Andrew Myers | 13 Aug 2011
New neurological measurement technologies and algorithms are allowing researchers a more complete look into how the brain functions. Engineers at Stanford are using these tools to better understand how the brain prepares to instruct the body to make a motion and why sometimes we react more quickly than others.
In 1991, Carl Lewis was both the fastest man on earth and a profound long jumper, perhaps the greatest track-and-field star of all time in the prime of his career. On June 14 of that year, however, Carl Lewis was human. Leroy Burrell blazed through the 100 meters, besting Lewis by a razor-thin margin of three-hundredths of a second. In the time it takes the shutter to capture a single frame of video, Lewis's 3-year-old world record was gone.
In a paper just published in the journal Neuron, a team at the Stanford School of Engineering, led by electrical engineers Krishna Shenoy and Maneesh Sahani, explored the neurological explanations for why Lewis may have lost that day. The team, which included graduate students Afsheen Afshar, Gopal Santhanam and Byron Yu and postdoctoral researcher Stephen Ryu, studied how the brain plans for and executes movements in reaction to a "go" signal.
The advent of new measurement technologies that permit researchers to monitor up to hundreds of individual neurons simultaneously, combined with new analytical mathematics, are providing a revealing look inside the brain and a better understanding of the neurological processes behind the planning and execution of motion.
"This research holds great promise in many areas of neuroscience, in particular human prostheses that can be controlled by the brain," said Shenoy.
The ability of humans to time the onset of planned movements is imprecise, often frustratingly so. In Carl Lewis' case, that imprecision cost him the race and the record. In fact, experts later pointed out that Burrell was not really the faster man that day; he was merely the faster off the blocks, beating Lewis at the gun by about five one-hundredths of a second, a difference that provided the margin of victory.
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