Tactile signals transmitted by the vibrissa during active whisking behavior

Abstract

The rodent vibrissal-trigeminal system is one of the most widely used models for the study of somatosensation and tactile perception, but to date the field has been unable to quantify the complete set of mechanical input signals generated during natural whisking behavior. In this report we show that during whisking behavior of awake rats ( Rattus norvegicus), the whisker will often bend out of its plane of rotation, generating sizeable mechanical (tactile) signals out of the plane. We then develop a model of whisker bending that allows us to compute the three-dimensional tactile signals at the vibrissal base during active whisking behavior. Considerable information can be lost if whisking motions are considered only in two dimensions, and we offer some suggestions for experimentalists concerned with monitoring the direction of bending. These data represent the first quantification of the physical signals transmitted to the mechanoreceptors in the follicle during active whisking behavior.

Mechanical responses of rat vibrissae to airflow

“…Shorter whiskers have higher intrinsic curvature Towal et al, 2011;Quist and Hartmann, 2012), explaining why the effect of orientation angle appears to be related to whisker length. From a mechanical point of view, the intrinsic curvature of the whisker allows it to 'twist' about its own axis, and will have a nonlinear effect on both axial force and bending (Huet et al, 2015;Huet and Hartmann, 2016). The results for the longer and shorter whiskers are averaged in Fig.…”

“…As in previous work (Towal et al, 2011;Quist et al, 2014;Huet et al, 2015), the x-axis was defined to lie along the proximal portion of the whisker (Fig. 1A, inset).…”

“…In contrast, when the whiskers are protracted against an object, they will tend to slip in different directions depending on their kinematic trajectory, their intrinsic curvature, object geometry and friction Hartmann, 2008, 2010;Hobbs et al, 2016;Huet et al, 2015;Huet and Hartmann, 2016).…”

The mathematical whisker: A review of numerical models of the rat׳s vibrissa biomechanics

“…This is the most recent publication by a scientific work team (Huet et al, 2015;Quist and Hartmann, 2012;Hartmann, 2006, 2011;Birdwell et al, 2007) about quasi-static models that study the relationship between the bending of the vibrissa and the forces and moments at the base. Huet et al (2015) quantified the variation in the vibrissa curvature in the case of slow collision against a peg in a 3D space.…”

“…Huet et al (2015) quantified the variation in the vibrissa curvature in the case of slow collision against a peg in a 3D space.…”