The transgenic construct contains HS4 insulator-Tet response element/promoter (pTRE2)-loxP-Stop-loxP-CaMP8m-WPRE-pA-HS4 insulator-pCAG-lox2272-Stop-lox2272-FLAG-IRES-tTA2-WPRE-pA cassette was introduced to the Igs7 intergenic region. GCAMP8m (medium) incorporates a hexa-histidine affinity tag, an endothelial nitric oxide synthase peptide (ENOSP; modified with N19T, S24I, A25G, and S26R), a circularly permutated green fluorescent protein (cpGFP; modified with Q88E), the rat calcium-binding protein calmodulin (CaM; modified with F286Y), and LKI amino acid linkers that replace the RS20 (previously referred to as M13) linkers. (J:101977)