How does the brain decide to approach others? Researchers found that coordinated brain activity linked to social behavior begins seconds before movement starts. Using zebrafish, they identified a key role for the pallium, a higher brain region required for normal social interaction, and showed that animals with a stronger brain-wide neural signature were more socially engaged overall. The findings suggest that the brain prepares for social interaction before the movement even begins, and that the strength of this preparation reflects an individual's social drive.
A new study from the laboratory of Dr. Lilah Avitan at the Hebrew University of Jerusalem sheds light on one of the most basic yet mysterious behaviors in biology: why and how we choose to approach others. The research, led by Avitan and carried out by PhD student Imri Lifshitz together with other members of her lab at the Edmond and Lily Safra Center for Brain Sciences (ELSC) at Hebrew University, shows that social interaction is preceded by a distinct brain-wide neural process .
To understand how social decisions are formed, the researchers turned to zebrafish, a model organism that allows scientists to observe brain activity at single-cell resolution.
They developed a novel setup in which one fish observed and reacted to another swimming fish, while its entire brain activity was recorded in real time. This allowed the team to capture, moment by moment, how the brain processes social information and turns it into action.
The team found that when a fish is about to move toward another, its brain begins to change several seconds before the movement occurs.
Rather than a single "social center," this process involves a distributed coordinated shift across the brain:
- Activity rises in the pallium, a higher brain region linked to complex behavior
- At the same time, activity drops in other regions
This pattern forms a kind of neural "pre-decision state" that signals an upcoming social action and can be used to predict it before it happens.
Importantly, the strength of this "pre-decision state" was linked to individual social drive: animals showing a stronger brain-wide pattern were more social overall. The findings also pointed to a central role for the pallium in generating this social drive, identifying it as a key brain region that helps promote approach toward others.
"This study identifies a brain-wide neural signature of social approach that emerges before movement begins," said Dr. Avitan. "This signature predicts not only whether an upcoming action will be social, but also how strongly socially driven the individual is."
Understanding how the brain generates social behavior could help explain why individuals differ in sociability. Because similar brain structures are involved in social behavior across species, these findings may also provide insight into human social function and disorders where it is disrupted.
