Investigating the relationship between cue immersion and the strength of motor imagery during hand and wrist movements

Virtual reality (VR) has gained popularity as a modality for motor imagery (MI) cue presentation for brain-computer interfaces due to the increased cortical activity caused by the immersiveness of the medium. In this work, we show that increased immersion alone is not sufficient to generate a greater cortical response during MI. We demonstrate this relationship through a MI protocol performed using three modalities of cue presentation, Image, Video, and VR, wherein intact limb participants were instructed to imagine the prompted hand and wrist movements as their own. Cue presentation using static images outperformed cue presentation using both traditional videos and immersive VR simulations (p < 0.05) in terms of percent change in relative alpha power. These results imply that providing more immersive cues may sometimes reduce the effectiveness of MI, possibly by inducing action observation rather than mental simulation.