Evidence for Functional Groupings of Vibrissae across the Rodent Mystacial Pad
Fig 5
Reachable configuration space of the array.
A. Reachable space for the 31 vibrissae of the left array. The figure shows the configurations that allow at least one vibrissa of the left array to come in contact with an infinite surface. Both resting-contacts and whisking-contacts are included. Color indicates the number of vibrissae that make contact. Configurations in which no vibrissae contact the surface are left white (labeled “unreachable”). The broad red peak at the level of the white dashed line indicates that at any given value of yaw, pitches around 0° will maximize the number of whisker contacts with the surface. B. Reachable and unreachable spaces for both sides of the array acting together. The configuration space over which no vibrissae, from either the right or left side of the array, make contact is extremely small until the distance becomes large. The unreachable region is colored gray and labeled “unreachable.” C. Example “walls” at different orientations relative to the rat’s head demarcate the unreachable space. The dotted lines show that a wall directly in front of the rat’s nose (pitch = yaw = 0°, cyan) becomes unreachable at a smaller distance than a wall to the rat’s side (orange and purple walls) or below the rat (green wall). D. The “blind spot” is very different from the unreachable space. The blind spot is a small (x, y, z) region of space that the whiskers cannot touch, even at extreme protraction angles. The left subplot indicates a protraction of 60° from rest, and the blind spot takes the form of a niche in front of the rat’s nose. At protractions of 70° and 90° (right plot), a number of simulated whiskers become un-physical (they penetrate the rat’s face due to excessive protraction) and yet the small blind spot remains. Note that an imaginary vertical surface (gray line) passing through a central point in the blind spot is not un-reachable because some vibrissae can still contact it.