Chemogenetic techniques such as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) enable transient, reversible, and minimally invasive manipulation of neural activity in vivo. Their development in non-human primates is essential for uncovering neural circuits contributing to cognitive functions and their translation to humans. One key issue that has delayed the development of chemogenetic techniques in primates is the lack of an accessible drug-screening method. Here, we utilize resting-state functional MRI (rs-fMRI), a non-invasive neuroimaging tool, to assess the impact of deschloroclozapine (DCZ) on brain-wide resting-state functional connectivity in seven rhesus macaques (6 males and 1 female) without DREADDs. We found that systemic administration of 0.1 mg/kg DCZ did not alter the resting-state functional connectivity. Conversely, 0.3 mg/kg of DCZ was associated with a prominent increase in functional connectivity that was mainly confined to the connections of frontal regions. Addit...