From seeing to showing: towards a neuroscience of emotion production.

Facial expressions are considered a critical feature in affective neuroscience. Consequently, extensive research has focused on how emotional facial expressions are perceived, including investigations into which brain regions are activated during their observation and how the brain processes their social significance. To advance a more comprehensive understanding of emotion, it is essential to examine all three aspects-perception, experience and production-in a balanced manner. From an evolutionary perspective, the production of facial expressions during emotional experiences is particularly significant, as it reflects both adaptive communication and survival functions. Nevertheless, a review of existing databases reveals that research on the production of facial expressions remains scarce compared with studies on perception. This gap may stem from several methodological constraints, including the difficulty of reliably inducing emotional experiences in laboratory settings, the challenge of recording participants' full facial expressions in a magnetic resonance imaging scanner and limitations in current analytical approaches for facial expressions. In this review, we argue for the importance of studying the production of facial expressions and outline potential strategies to address these challenges. This article is part of the theme issue 'Mechanisms, development, phylogeny and functions of emotional expressions'.