Figure 3.

Myelinated Hair Afferents Are a Principal Source of Afferent Input to Inhibitory PV Cells in Laminae IIi and III

(A and B) Representative examples of inhibitory PV cells in tissue from Split^Cre; Ai34 (A) or TrkB^CreER; Ai35 (B) mice. Higher magnification insets show the presence of Pax2-immunolabelling (gray) in the nuclei of these cells.

(C and D) Reconstructions of the individual inhibitory PV interneurons shown in (A) and (B), respectively, showing the relative positions of contacts from VGLUT1-only (blue diamonds) and Aβ- (C) or Aδ-hair (D) afferent terminals (magenta circles) plotted onto their cell body and dendrites.

(E and F) Examples of dendrites from these PV-expressing inhibitory interneurons receiving multiple contacts from axon terminals that either express only VGLUT1 (blue, arrows), tdTom-labeled boutons of Aβ-hair afferents (red; arrowheads in E) derived from Split^Cre;Ai34 mice, or YFP-expressing Aδ-hair afferents (green; double arrowheads in F) from TrkB^CreER;Ai35 mice.

(G) Mean number of contacts from Aβ- and Aδ-hair afferent terminals per inhibitory PV soma.

(H) Mean number of contacts from Aβ- and Aδ-hair afferent terminals per 100 μm of dendrite of inhibitory PV interneurons.

(I) Relative proportion of all VGLUT1 terminals contacting the soma and dendrites of inhibitory PV cells that are derived from Aβ- and Aδ-hair afferents.

Bars in (G)–(I) show means across all animals, and individual points show the means of each animal. n = 3 mice per afferent class, with three or four inhibitory PV cells analyzed per mouse. Scale bars represent 25 μm (A and B), 100 μm (C and D), and 5 μm (E and F).