Smiles and frowns are planned by a whole network of brain regions, Science study finds

Every smile, grin or frown is a small act of communication, and for decades neuroscientists believed the brain produced them through two separate channels. Deliberate, voluntary expressions were thought to come from lateral regions of the frontal cortex, while spontaneous emotional ones were attributed to medial regions, a view built partly on observations of patients with localised brain damage. A study published in Science on 8 January 2026 suggests that picture is too simple.

The research was led by Professor Yifat Prut of the Edmond and Lily Safra Center for Brain Sciences at the Hebrew University of Jerusalem and Professor Winrich Freiwald of Rockefeller University in New York, with first author Geena Ianni and colleagues at the University of Kansas Medical Center and the University of Rochester. The team recorded the activity of individual neurons across both the lateral and medial face-control regions of the frontal lobe during the production of different facial gestures.

They found that both sets of regions carry information about voluntary and emotional expressions alike. Rather than dividing the work by type of gesture, the areas form a continuous hierarchy that works together, with some regions producing fast-changing signals and others steadier, sustained ones. Strikingly, the neural patterns for a given expression could be told apart before any movement appeared on the face, showing that the brain begins preparing a social signal well in advance.

The authors suggest the findings could help explain how facial communication breaks down after brain injury or in conditions that affect social signalling, and might eventually inform efforts to restore or decode facial expression.