Visual-Semantic Tuning across the Cortex Shifts between Tasks.

Attention is a powerful mechanism that dynamically optimizes brain representations to prioritize behaviorally relevant information. While previous studies focusing on single tasks have demonstrated that attention shifts tuning toward attended targets, real-world behavior often requires humans to switch between tasks with different demands. How does visual-semantic tuning in the human brain shift to support the behavioral demands of different naturalistic tasks? To investigate this question, we used voxelwise encoding models to explore how visual-semantic tuning across the human cerebral cortex shifts between two naturalistic human fMRI experiments that used distinct tasks, movie-watching (five male participants) and active navigation (six participants, three male, three female). Results show that visual-semantic tuning in the cortex differed substantially between experiments. Principal component analysis reveals that during navigation, tuning shifts increase the representation of vehicles and traffic signs compared with movie-watching and that these shifts are localized to distinct functional networks. These tuning shifts reconfigure the human brain's representations of object categories based on their behavioral relevance. These findings suggest that visual-semantic tuning in the brain dynamically shifts toward task-relevant information across naturalistic tasks, optimizing functional representations to achieve diverse behavioral goals.