Sensory signals for motor control during active sensing

Tactile exploration in the rodent whisker system is a sensorimotor process in which whisker touch modulates whisker motion. Understanding the neural computation underlying object localization requires quantification of this sensorimotor feedback in freely behaving animals. Here, using high- speed imaging of tactile exploration, we found that mice precisely match their whisk amplitude to anticipated object location in each whisk-cycle. This modulation does not depend on the current sensory input, but is controlled by the information collected during previous whisk-cycles. Timing and other properties of contact induced whisker deformations in the current cycle encode the error in animal's expectation for the object distance. We suggest a framework for sensorimotor computation during object localization where anticipatory and precise modulation of whisker protraction amplitude compensates recent body motion and encode object location, while properties of whisker contacts such as the timing relative to the motor pattern encode the error in this estimate.