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 14th of that year, however, Carl Lewis was human. Leroy Burrell blazed through the 100-meters, besting him 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 three-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, Byron Yu, and post-doctoral 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's 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.
"Lewis may well have lost because he wasn't able to optimize his own motor plan and thus his reaction time was slow," said Shenoy.
|Contact: Andrew Myers|
Stanford School of Engineering