Increased attentional resources may be required to maintain standing balance under conditions of altered visual and somatosensory feedback among healthy adults.

Somatosensory feedback provides ongoing representation of the body's movements and interaction with the environment that is important for postural control. Altered somatosensory feedback may require compensation to maintain balance, which could include greater attentional resources or increased reliance on other sensory modalities to maintain posture through sensory reweighting. The prefrontal cortex (PFC) has been implicated in allocating attentional resources to maintain postural control, which may be associated with reweighting among sensory modalities. It is unknown whether increased PFC activity will compensate for altered sensory feedback and will be associated with sensory reweighting, demonstrated by changes in visual and somatosensory cortical activity. Therefore, the purpose of this study was to evaluate the contribution of attentional resources and sensory reweighting to postural control, assessed by changes in cortical activity and body sway under conditions of altered sensory feedback during standing. Fifteen healthy, neurotypical participants (ages 21-58) completed somatosensory testing and the Modified Clinical Test of Sensory Interaction in Balance whilst activity in the PFC, somatosensory, visual and motor cortices was measured using functional near-infrared spectroscopy, and an inertial sensor tracked postural sway. Increased postural sway and PFC activity were evident with vision occluded and unstable surface. Somatosensory, visual and motor cortices demonstrated chromophore and side-specific differences that may reflect the range of age and somatosensory function among the sample cohort and suggest that a threshold of sensory challenge may be necessary to evoke cortical changes. However, increased PFC activity supports increased reliance on attentional resources to maintain balance in response to sensory challenge.