The corticolimbic network plays a significant role in regulating emotional behavior. Stress-induced dysfunctions in this network are associated with mental illnesses, including major depressive disorder (MDD). Despite being one of the most prevalent mental disorders, the pathogenic mechanisms of MDD remain unclear. Serotonin has been associated with MDD as a promising factor for over 60 years. However, serotonergic dynamics have only recently been linked to corticolimbic network activity. We aim to investigate the effect of serotonin on corticolimbic network activity, specifically in the medial prefrontal cortex, amygdala, and hippocampus. To achieve this, we established an implantation in mice that allows multiregional electrophysiological recordings and optogenetic release of serotonin simultaneously. Our findings demonstrate, for the first time, the impact of serotonin on the synchronization between brain regions of the corticolimbic network.