Abstract

By a Whisker Every student learns that the sensory cortex is used for processing sensation and the motor cortex is used for perceiving movement. However, in the real world, this may not always be so neatly arranged. Matyas et al. (p. 1240 ) have found that sensory and motor fields are specialized for different types of movement, such that in mice the motor cortex controlled the forward movement (protraction) of their whiskers and the sensory cortex controlled backwards movements (retraction) of whiskers. So if a whisker hits an object, then a reasonable first reaction might be a motor command for retraction. Similarly, the motor cortex stimulates protraction for more active exploration. Hence, the sensory cortex is also motor and the motor cortex is also sensory. In an ecological context, these combined reactions offer a repertoire useful for a mouse seeking food and shelter in a complex environment.