In the 3-chamber test, the subject mouse of the PBS-treated mice and the CNO-treated mice explored freely the three test chambers. The time spent in each chamber during two sessions was measured. The CNO-treated ChAT(+)-cre::hM4D(Gi) mice exhibited a decreased interest for a stranger mouse (S1) against objects (O) compared to the PBS-treated group (left two panels) (nCTL=6, ncKO=9, unpaired Student t-test). I. When CNO-treated ChAT(+)-cre::hM4D(Gi) mice were exposed to a new stranger mouse (S2) against the familiar S1 mouse, they also showed a decreased interest for the S2 mouse compared to the PBS-treated control group (right two panels). The preference index showed decreased sociability of the CNO-treated group in both sessions (nCTL=6, ncKO=9, unpaired Student t-test;). 