Modulation of cortical activity in response to visually induced postural perturbation: combined VR and EEG study.

There is evidence from EEG studies that unexpected perturbations to standing posture induce a differential modulation of cortical activity compared to self-initiated and/or predictable conditions. However, the neural correlates of whole body postural response to visually induced perturbations on standing posture have not been examined. Here we employ a novel experimental paradigm via combined virtual reality (VR) and EEG measures to examine the effects of visually induced perturbations on the dynamics of postural responses. Twelve Penn State student-athletes without prior history of neurologic disorders and/or orthopaedic injuries participated in this study. There were no differences in response/reaction time measures between both spatially and temporally unpredictable and fully predictable conditions (p>.05). However, significantly stronger modulation of frontal-central EEG theta activity was present prior to onset of unpredictable postural perturbations (p<.05). It is postulated that enhanced EEG theta in unpredictable conditions reflects increased effort to recruit additional brain resources to meet the demands of the postural tasks.