Increased Cognitive Load Expands, Stabilizes, and Aligns Visual Representation Across the Human Brain

Cognitive load refers to the mental effort required to perform a task. While previous research has extensively examined its detrimental effects on neural and behavioral performance, much less is known about how the brain actively adapts to heightened demands. Across two fMRI experiments involving visual n-back tasks, we identified several fundamental properties of this adaptive process. First, higher load enhanced and expanded visual representations beyond localized visual regions, leading to widespread visual coding. At the global scale, heightened load promoted cross-regional coordination by increasing representational alignment and strengthening information encoded in interregional functional connectivity patterns. Beyond facilitating stronger visual representation, increased load also reduced neural pattern variability, which led to more stable information coding. Finally, load was encoded independently of other task-relevant information as a separate brain state, supporting its overarching role in guiding visual processing. Together, these findings revealed that the brain adapts to heightened cognitive demands by globally reorganizing neural processing to support flexible cognition.