Frisking the whiskers: patterned sensory input in the rat vibrissa system.

How are two prominent environmental features, surface texture and object location, transduced and encoded as rats whisk? Recent papers show that textures may excite intrinsic mechanical vibrations of the vibrissae. Although these vibrations are too rapid to be directly followed by cortical neurons, there is evidence that their speed is encoded by contact-dependent sensory signals. In addition to contact, sensory signals exist that report the angular position of the vibrissae. The combination of contact and reference signals may be used to decode spatial variations in the environment, particularly the location of objects in head-centered coordinates.