Figure 1
Localization and size distribution of the TG neurons innervating the dura and periorbital skin. (A) Representative image of a TG section showing FG-labeled (FG+) dural afferent neurons. Note that the labeled neurons are distributed predominantly within the V1 division and to some extent in the V2 division. (B) High-magnification image of the region indicated in (A). (C) Representative image of DiI-labeled (DiI+) dural afferent neurons. (D) The distributions of FG+ and DiI+ in the skin and dural afferent neurons from the three TG divisions (n = 3–4 mice in each group; on average, 200 labeled neurons from each mouse were counted). The majority of labeled neurons are distributed in the V1 and V2 divisions (one-way ANOVA with post hoc Bonferroni test, *** p < 0.001, V1 versus V2 or V3 distribution in each group; # p < 0.05, ### p < 0.001, V2 versus V3 distribution in each group). (E) Histogram of the size distributions of total TG neurons in the V1/V2 divisions, FG+ skin afferent neurons, and FG+ dural afferent neurons (n = 2316, 600 and 2208 neurons pooled from three mice, respectively). (F) Cumulative distributions of the cross-sectional areas of total TG neurons in the V1/V2 divisions, FG+ skin afferent neurons, and FG+ dural afferent neurons (the same neurons as in E). The sizes of dural afferent neurons are significantly larger than those of the skin afferents and the V1/V2 TG neurons (p < 0.001, Kruskal-Wallis ANOVA with Dunn’s post hoc test).