Figure 4.

pBLA in the Pcdh9 KO mice. (a–h) The size of pBLA, visualized with a marker of BLA neurons (COUP-TFII), was not affected in the KO mice. (i–p) Double staining of COUP-TFII and DARPP-32 (Ppp1r1b), a marker of fear extinction neurons. (q) The number of DARPP-32⁺ neurons was not changed in the pBLA of the KO mice. (r) Double staining of c-fos (red) and DARPP32 (green) after a water reward. (s) c-fos expression in the DARPP-32⁺ neurons was not different between the wt mice and the Pcdh9 KO mice without a water reward, whereas it was significantly higher in the Pcdh9 KO mice than that of the wt mice after a water reward. In the case without water reward, the numbers of c-fos⁺ and DARPP-32⁺ were counted with 10 sections from two wt mice and 12 sections from two Pcdh9 KO mice, whereas in the case with water reward, the numbers of c-fos⁺ and DARPP-32⁺ were counted with 28 sections from five wt mice and 30 sections from six Pcdh9 KO mice. Scale bars, 200 μm in (a–h) and 20 μm in (i–p, r).