Differential neural activation in healthy older adults compared to subjects with Parkinson's disease during motor imagery of walking in virtual environments

The neural correlates of locomotion in complex environments are unclear. Twenty healthy older adults and 20 patients with Parkinson's disease (PD) were asked to imagine walking in different virtual environments in MRI scanner. Whole brain analyses were performed. Between group comparisons revealed that patients with PD had a significantly higher activation already during imagined usual walk. However, comparisons between walking tasks showed increased activation during imagined complex walking tasks only in healthy older adults. This increased activation in patients with PD act as a compensatory strategy that limits the ability to recruit additional brain areas during more demanding walking tasks.