title: The functional organization of cutaneous low-threshold mechanosensory neurons.
abstract: Innocuous touch of the skin is detected by distinct populations of neurons, the low-threshold mechanoreceptors (LTMRs), which are classified as Aβ-, Aδ-, and C-LTMRs. Here, we report genetic labeling of LTMR subtypes and visualization of their relative patterns of axonal endings in hairy skin and the spinal cord. We found that each of the three major hair follicle types of trunk hairy skin (guard, awl/auchene, and zigzag hairs) is innervated by a unique and invariant combination of LTMRs; thus, each hair follicle type is a functionally distinct mechanosensory end organ. Moreover, the central projections of Aβ-, Aδ-, and C-LTMRs that innervate the same or adjacent hair follicles form narrow LTMR columns in the dorsal horn. These findings support a model of mechanosensation in which the activities of Aβ-, Aδ-, and C-LTMRs are integrated within dorsal horn LTMR columns and processed into outputs that underlie the perception of myriad touch sensations.
authors.affiliation: The Solomon H Snyder Department of Neuroscience and Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Lishi
authors.initials: L
authors.lastname: Li
authors.forename: Michael
authors.initials: M
authors.lastname: Rutlin
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Abraira
authors.forename: Colleen
authors.initials: C
authors.lastname: Cassidy
authors.forename: Laura
authors.initials: L
authors.lastname: Kus
authors.forename: Shiaoching
authors.initials: S
authors.lastname: Gong
authors.forename: Michael P
authors.initials: MP
authors.lastname: Jankowski
authors.forename: Wenqin
authors.initials: W
authors.lastname: Luo
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Heintz
authors.forename: H Richard
authors.initials: HR
authors.lastname: Koerber
authors.forename: C Jeffery
authors.initials: CJ
authors.lastname: Woodbury
authors.forename: David D
authors.initials: DD
authors.lastname: Ginty
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology; D006197:Hair / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000502:physiology; D012684:Sensory Thresholds; D012867:Skin / Q000166:cytology / Q000294:innervation*; D012879:Skin Physiological Phenomena; D013116:Spinal Cord / Q000502:physiology