This project aims to understand how neuronal population activity can be decoded in the context of emotional contagion during social interactions. When an individual observes the emotional state of a conspecific, emotional contagion provides a behavioral and physiological context through which underlying neural dynamics can be interpreted. By combining large-scale neural recordings with rich behavioral and physiological measurements, including facial expression analysis, body pose estimation, and other autonomic or movement-related signals, the project seeks to decode patterns and transitions in neuronal population activity associated with socially driven internal states. Rather than relying on predefined emotional labels, a data-driven approach is used to identify emergent coordinated neuronal population activity dynamics that align with changes in observed social and physiological cues regarding emotional contagion. This work contributes to approaches for interpreting high-dimensional neural activity by relating neuronal dynamics to naturalistic social behavior and multimodal physiological markers, bridging population-level brain activity and observable emotional and social state changes.