Neural network dynamics associated with facial and subjective emotional responses

Emotions comprise multiple coordinated responses, including facial expressions and subjective experiences. Although functional magnetic resonance imaging (fMRI) studies have identified brain regions associated with facial or emotional responses, few have simultaneously assessed and statistically dissociated components. Additionally, the functional networks associated with these emotional responses and the dynamic interplay between such networks remain uncertain. To investigate these issues, we measured fMRI while participants viewed emotional films, as well as their facial videos and dynamic valence ratings. Regional activity analysis revealed that facial responses (lip-corner-pulling actions) were associated with activation in the limbic regions and somatosensory motor cortices. Subjective emotional responses (the absolute values of valence ratings) were associated with activity in the medial parietal and lateral temporoparietal cortices. Independent component analysis revealed that the independent components associated with facial and subjective responses included the abovementioned activated regions. Dynamic causal modeling of these independent components supported a model in which the visual/auditory processing component modulated the facial response component, which subsequently influenced the subjective response component. Our findings imply that, during emotional processing, facial responses are initially generated by the limbic and sensorimotor cortical networks; subsequently, these responses give rise to subjective experiences through activity in the medial parietal-lateral temporoparietal networks.