Movement kinematics of rodent whisking

2012-11-08T05:14:51Z (GMT) by P K
<p>The relative simplicity of the rodent vibrissal system facilitates a systematic study of motor control and sensorimotor loop dynamics. Multiple anatomical loops contribute to active control of the vibrissal plant during explorative behavior. We have examined motor control during exploratory and task-related whisking in rats and mice. Using high-speed video we monitored whisker trajectories and extracted various kinematic parameters from the whisker motion. We analyzed repetitive whisker movements with a forward (protraction) and a backward (retraction) phase. We found that, across tasks, the protraction phase during high-amplitude whisks is characterized by a pulsatile forward motion with relatively constant velocity. The amplitude of protraction is governed primarily by the duration of movement whereas retraction amplitude scales primarily with velocity. During protraction, object touch is followed by a rapid (~10 ms) active thrust of the ongoing movement, typically observed as an increase in whisker velocity. These observations are consistent with the notion that the protraction phase acts as the sensory acquisition stage during whisking and that rapid brain loops can process and adjust pre-planned movement trajectories in the behaving rodent.</p>