Social behavior is defined as any communication or interaction between two conspecifics of a given species encompassing various forms and contexts. Previous studies have shown that mice have social cognition that enables them to integrate, interpret, and respond to social signals and use these signals for the guidance of flexible and appropriate responses in different social contexts. One brain region with established involvement in social cognition is the medial prefrontal cortex (mPFC). However, the exact role of the mPFC in social decision-making in different contexts remains poorly defined. In this study, we used two social discrimination tasks where subjects were introduced to social stimuli of varying appeal- Social Preference (SP) and Stress State Preference (SSP) tasks. We recorded the bulk activity of mPFC pyramidal neurons in-vivo using fiber photometry in adult male C57BL\6J mice while performing these tasks. We also manipulated the activity of mPFC pyramidal neurons using optogenetic stimulation to elicit excitation. Pyramidal neurons in the mPFC showed significant opposite responses specific to long bouts of investigation (>6 sec) with the preferred vs. less-preferred stimuli in both tests. However, while in the SP task, the differential response persisted throughout the investigation bout, in the SSP task, the differential response was more transient. Short optogenetic excitation did not affect social preference, while it was sufficient to affect emotion recognition in the SSP task. Interestingly, the responses of mPFC pyramidal neurons to various stimuli were found to be sensitive to whether the subject was group-housed or isolated.