Demonstration of three-dimensional contact point determination and contour reconstruction during active whisking behavior of an awake rat

Abstract

The rodent vibrissal (whisker) system has been studied for decades as a model of active touch sensing. There are no sensors along the length of a whisker; all sensing occurs at the whisker base. Therefore, a large open question in many neuroscience studies is how an animal could estimate the three-dimensional (3D) location at which a whisker makes contact with an object. In the present work we simulated the shape of a real rat whisker to demonstrate the existence of several unique mappings from triplets of mechanical signals at the whisker base to the three-dimensional whisker-object contact point. We then used high speed video to record whisker deflections as an awake rat whisked against a peg, and used the mechanics resulting from those deflections to extract the contact points along the peg surface. These results demonstrate that measurement of specific mechanical triplets at the base of a biological whisker can enable 3D contact point determination during natural whisking behavior. The approach is viable even though the biological whisker has non-ideal, non-planar curvature, and even given the rat’s real-world choices of whisking parameters. Visual intuition for the quality of the approach is provided in a video that shows the contour of the peg gradually emerging during active whisking behavior.

Two modes in the velocity statistics in cautious walks of laboratory rodents

“…Information on both larger scale motions (locomotion) and smaller movements is likely contained in many laboratory studies of movements that use motion tracking [58, 59]. The most common frontal view used to monitor test animals will pick up small movements of the head and the torso.…”

The Anterolateral Barrel Subfield Differs from the Posteromedial Barrel Subfield in the Morphology and Cell Density of Parvalbumin-Positive GABAergic Interneurons

“…This structural design suggests a mode of sensory detection that is executed by a large number of small-sized units, which might underlie high-resolution sensing using microvibrissae when animals discriminate fine texture ( Kuruppath et al, 2014 ) and shape of objects ( Brecht et al, 1997 ). In contrast, information on space such as distance and orientation will be acquired most probably through long and mobile macrovibrissae ( Knutsen et al, 2006 ; Pammer et al, 2013 ; Grant et al, 2018 ; Huet et al, 2022 ). These differential properties of the two vibrissal types are thought to be reflected in morphological differences between the two barrel subfields, though it remains to be studied how functional differences in peripheral sensing apparatus result in differences that we quantified in cortical unitary structures.…”

“…e N e u r o A c c e p t e d M a n u s c r i p t as distance and orientation will be acquired most probably through long and mobile macrovibrissae (Knutsen et al, 2006;Pammer et al, 2013;Grant et al, 2018;Huet et al, 2022). These differential properties of the two vibrissal types are thought to be reflected in morphological differences between the two barrel subfields, though it remains to be studied how functional differences in peripheral sensing apparatus result in differences that we quantified in cortical unitary structures.…”