The effects of manipulation of visual feedback in virtual reality on cortical activity: A pilot study

It is known that systematic visual distortions using virtual reality technologies, prisms or mirrors, may have therapeutic effects for patients suffering from stroke or body image identity disorders. However, there are few studies which directly investigate neural activity changes during visual feedback manipulation. In the present study we created an experimental setup for investigating the effects of systematic virtual reality-mediated visual feedback manipulation of finger movements on cortical activity. We performed tests with two healthy female subjects who performed a line-tracking task under four conditions manipulating visual feedback of their own hand. To investigate hemodynamic responses in motor areas during the line tracking task we used functional near-infrared spectroscopy (fNIRS). We predicted that viewing larger or smaller virtual movements of fingers, compared to the real movements, would affect activity in motor areas and thus the hemodynamic response. Our preliminary results showed changes in the hemodynamic responses between stimulation period and baseline. There were indications of possible differences between conditions, and also of adaptation effects within conditions. However these effects were not significant in our preliminary data and we therefore need to collect additional data to draw further conclusions.