Neural signals gradually shift towards inferior frontal gyrus and long-term effects following facial imitation-based...

Despite its complexity, social learning is widespread, with humans navigating social environments with ease. However, the spatiotemporal trajectory of brain changes during facial imitation-based social learning (FISL) remains unestablished. In this study, participants (N = 80) learned to imitate facial emotions across 16 sessions over one month, with mirror neuron system (MNS) activity measured via fNIRS at three timepoints. fMRI assessed long-term effects of FISL on social perception. Our findings revealed that positive FISL was facilitated by changing spatiotemporal pattern similarity within the MNS, enhancing initial imitative performance and accelerating later learning speed. As sessions increased, information flow shifted from MNS synergy toward greater inferior frontal gyrus dominance. Furthermore, long-term FISL enhanced emotional faces not scenes perception, with increased connectivity between MNS and social cognition regions (e.g., orbital frontal cortex). These results advance our understanding of the spatiotemporal dynamics of social learning, potentially informing neurorehabilitation approaches for social deficits through imitation-based interventions.