Meeting Abstract
Facial (mystacial) vibrissae, a kind of sinus hairs within the group of tactile hairs, have been intensively studied for muscle activities, neurological patterns, anatomy details and their biological role in different species. The skill to move in a more or less regular pattern (whisking) is known from various species, like rats. In addition to these whiskers rats have other sinus hairs, e.g. the non-moving carpal ones on the forelimbs. It has been assumed that carpal sinus hairs have a sensory function during locomotion on different substrates by detecting discontinuities while whiskers detect vertical obstacles. The possibility of a coupled sensorimotor control between the limbs and the sinus hairs might lead to a stabilized locomotion over uneven substrate. To test this hypothesis several spatiotemporal speed dependent parameters as well as kinematic data for the limbs were quantified and linked to the motion of carpal and facial sensors. Parameters were measured from x-ray and high-speed videos. A treadmill with continuous and discontinuous substrate was used. Rats had to walk under the presence and absence of the carpal and/or mystacial tactile hairs. Data were collected for a speed range of 0.2 to 0.5 m/s. Collecting tactile information by whiskers and carpal sinus hairs during touchdown and swing phase of the limbs is an important factor to get information about the substrate where the limb is going to be placed next. Loss of the sinus hairs affected the degree of parameter variation but not average parameters or the failure rate of the limbs during walking on the perforated treadmill. The motion of whiskers is affected by the presence/absence of the carpal sinus hairs and might compensate the loss of this substrate sensor.
