Three-Dimensional Architecture and Linearized Mapping of Vibrissa Follicle Afferents

The study explores the three-dimensional architecture of vibrissa follicle afferents in rats using advanced imaging techniques, revealing a highly ordered axonal structure. It identifies three classes of axons, including 174 myelinated axons from the deep vibrissal nerve, and classifies 149 afferents into four types: Merkel, lanceolate, club-like, and Ruffini-like. The research highlights a proximal-to-distal gradient in axonal conduction velocity and a dorso-caudal innervation bias, suggesting evolutionary adaptations. A significant finding is the discovery of a previously unrecognized subclass of club-like afferents. The study concludes that large-scale reconstructions can improve understanding of vibrissal mechanotransduction and sensory mapping in the brain, although it is limited by the incomplete reconstruction of unmyelinated axons.