Fig. 7

Trpa1⁺ TG neurons contribute critically to 2MT-evoked innate freezing. a Hematoxylin and eosin staining of the control and lesioned TG of wild-type mouse after unilateral lesion (ulTGx). b Representative images showing c-fos ISH signals in the Sp5C regions of ulTGx mice after 2MT exposure. Enlarged images of the control (white arrow) and lesion sides (black arrow) are shown in the lower panels. Scale bars are 100 µm in a and b. c Quantitative analysis of c-fos ISH signals in the Sp5C regions of the control and lesion sides of ulTGx mice after 2MT exposure. The relative measure (%) of c-fos signals of the lesion side is normalized to that of control side. Data are presented as mean ± SEM (n = 8, Student’s t-test, **P < 0.01). d Quantitative analysis of 2MT-evoked freezing behavior in the sham (black) and ulTGx (red) mice. Data are presented as mean ± SEM (n = 8, Student’s t-test, **P < 0.01, ***P < 0.001). e Quantification of average freezing rate in the sham (black) and ulTGx (red) mice during 10 min of 2MT treatment. Data are presented as mean ± SEM (n = 8, Student’s t-test, *P < 0.05). f A schematic of bilateral injection of AAV-GFP or AAV-Trpa1 into the TG of Trpa1^−/− mice. g Representative IHC images of AAV-GFP-infected TG sections of Trpa1^−/− mice. GFP (green); c-Fos (red); DAPI (blue). h Representative images of double Trpa1/c-Fos staining of AAV-Trpa1-infected TG sections of Trpa1^−/− mice. Trpa1 ISH (purple); c-Fos IHC (brown). Arrowheads indicate Trpa1⁺/c-Fos⁺ TG neurons. Insets are high magnification images. Scale bar is 20 µm. i Quantitation of 2MT-evoked GFP⁺, c-Fos⁺, or Trpa1⁺/c-Fos⁺ TG double positive neurons in AAV-GFP or AAV-Trpa1-infected TG, respectively. j, k Quantitative analysis of 2MT-evoked freezing behavior in the AAV-GFP (blue) and AAV-Trpa1 (red)-injected mice. Data are presented as mean ± SEM (n = 6, Student’s t-test, *P < 0.05; **P < 0.01)