Task- and Subject-Related Differences in Sensorimotor Behavior during Active Touch

Abstract

Rats explore objects by rhythmically whisking them with their mystacial vibrissae. On two types of tactile discrimination tasks, macrogeometric and microgeome-tric, better performers palpated the discriminanda for longer periods of time and used movement patterns that appeared to optimize whisking frequency bandwidth and the tent to which the vibrissae would be bent by object contact. On a task involving finely textured surfaces, good and poor performers differed in the temporal components of their whisking patterns, whereas the spatial domain was more important for animals palpating surfaces with widely separated features. These findings are consistent with increasing neurophysiological evidence that the central representation of the tactile periphery, in rodents and other mammals, is both integrative and dynamic.

Key Words:

• vibrissae
• tactile
• texture
• whisking
• discriminative touch
• motor control
• learning