Compensatory cerebellar activation during fluid intelligence processing following mild traumatic brain injury.

Cognitive outcome following mild traumatic brain injury (mTBI) vary widely, with many individuals experiencing long-term impairments associated with frontoparietal network dysfunction. Mild TBI patients have demonstrated functional reorganization, suggesting an expansion of activation to cerebellar regions during specific executive functions. In this study, we investigated cerebellar involvement in fluid intelligence processing using a novel fMRI paradigm based on Raven's Progressive Matrices in 51 acute mTBI patients and 61 healthy controls. Despite comparable task accuracy, mTBI patients exhibited significantly increased activation in anterior cerebellar regions, including Vermis III and Cerebellum IV-V. Seed-based functional connectivity analysis further revealed altered cerebellar-frontoparietal interactions in mTBI patients compared to healthy controls. In mTBI patients, connectivity was enhanced with the left lateral prefrontal cortex and lower with the right posterior parietal cortex, which also showed a change from positive to negative connectivity. These findings suggest that the cerebellum is adaptively recruited to maintain cognitive performance, in line with the cerebellar reserve theory. This study provides initial evidence of cerebellar activation during fluid intelligence processing in mTBI, highlighting a potential role for the cerebellum in adaptively interacting with cortical networks to support cognitive function following brain injury.