Like a finely tuned harp, the whiskers on a rat's snout pick up particular frequencies and send these teensy signals to the brain. Now scientists have caught the whisker signals on video. Past research has shown that like harp strings, the shorter whiskers positioned at the front of rats' snouts are tuned to vibrate at higher frequencies and the longer ones at lower frequencies. These signals get sent to rodents' brains, where a large portion of their brain cells are devoted to decoding incoming whisker signals, making rats the super-sensors of the slum world. In the experiments, Ritt, Moore and their colleagues trained rats to use their whiskers to pick out either a smooth or a rough surface. A correct response garnered chocolate milk. "The vibrations due to the tip hitting the surface reach the base and in the rat's face the base is where all the nerve endings are," Ritt told LiveScience. "What it is going to be sensing is all the vibrations coming down the shaft of the whisker." The rough surfaces produced what the researchers termed "stick-slip-ring" events, in which a whisker would get caught by a bump on a surface and then suddenly slip forward, causing the shaft of the whisker to shake back and forth. Smooth surfaces produced a stream of infinitesimal "stick-slip" oscillations. "These patterns are larger and more complex than anything previously observed in anesthetized animals or plucked whiskers, but they are the key to a rat's perceptions and behavior," Moore said. http://www.msnbc.msn.com/id/23373403/
