Facial expressions arise from layered brain signals, macaque study finds
Mar 8th 2026
A Science study recording macaque brains shows smiles, threats, and chewing emerge from a time-layered network: slow signals set social meaning well before a face moves, and fast signals execute the motion.
- Researchers recorded neural activity across multiple brain regions while macaques produced lip smacks, threats, and chewing.
- Facial gestures were represented broadly across the cortex rather than by a single dedicated region.
- Different brain areas contributed on different timescales, with slow signals holding stable information and fast signals tracking moment-to-moment motion.
- Slow activity in regions linked to motivation and context could predict which gesture would occur nearly one second before movement.
- The system is organized by rhythm and timing rather than by discrete emotional categories.
- Results clarify how social meaning and precise muscle control are separated in the brain and may inform studies of Parkinsons disease, autism, and facial expression disorders.