February 06, 2008 — Quickly moving your fingertips to tap or press a surface is essential for everyday life to, say, pick up small objects, use a BlackBerry or an iPhone.  But researchers at the University of Southern California say that this seemingly trivial action is the result of a complex neuro-motor-mechanical process orchestrated with precision timing by the brain, nervous system and muscles of the hand.
USC Viterbi School of Engineering biomedical engineer Francisco Valero-Cuevas is working to understand the biological, neurological and mechanical features of the human hand that enable dexterous manipulation and makes it possible for a person to grasp and crack an egg, fasten a button, or fumble with a cell phone to answer a call. 

“When you look at the hand, you think, ‘five fingers, what could be more straightforward?’ ” Valero-Cuevas said, “but really we don’t understand well what a hand is bio-mechanically, how it is controlled neurologically, how disease impairs it, and how treatment can best restore its function. It is difficult to know how each of its 30-plus muscles contributes to everyday functions like using a cell phone or performing the many finger tasks it takes to dress yourself.”

In a study published online in the Feb. 6, 2008 issue of The Journal of Neuroscience, titled “Neural Control Of Motion-to-Force Transitions with the Fingertip,” Valero-Cuevas and co-author Madhusudhan Venkadesan of Cornell University’s Department of Mathematics asked volunteers to tap and push against a surface with their forefinger while the researchers recorded the fingertip force and electrical activity in all of the muscles of the hand. For more information:http://viterbi.usc.edu/news/news/2008/what-gives-us.htm