Topography of whisking II: interaction of whisker and pad.
The peripheral effector system mediating rodent whisking produces protraction/retraction movements of the whiskers and translation movements of the collagenous mystacial pad. To examine the interaction of these movements during whisking in air we used high-resolution, optoelectronic methods for two-dimensional monitoring of whisker and pad movements in head-fixed rats. Under these testing conditions (1) whisker movements on the same side of the face are synchronous and of similar amplitude; (2) pad movements exhibit the characteristic 'exploratory' rhythm (6-12 Hz) of whisking but their movements often have a low frequency (1-2 Hz) component; (3) Pad movements occur in both antero-posterior and dorso-ventral planes but there are considerable variations in the amplitude and topography of movement parameters in the two planes. We conclude that (a) both whisker and pad receive input from a common central rhythm generator; (b) differences in whisker and pad amplitude and topography probably reflect differences in the biomechanical properties of the structures receiving that input; (c) pad movements make a significant contribution to the kinematics of whisking behavior and (d) the two-dimensional nature of pad translation movements significantly increases the rat's flexible control of its mobile sensor.
Bermejo
R
R
Department of Psychology, Hunter College (CUNY), New York, NY 10021, USA.
Friedman
W
W
Zeigler
H P
HP
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D004576:Electromyography; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D009044:Motor Cortex / Q000502:physiology; D009068:Movement / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D010812:Physical Stimulation; D051381:Rats; D020318:Rats, Long-Evans; D013003:Somatosensory Cortex / Q000502:physiology; D014738:Vibrissae / Q000502:physiology*