Examining and Enhancing the Illusory Touch Perception in Virtual Reality Using Non-Invasive Brain Stimulation

Virtual reality (VR) can be immersive to such a degree that users sometimes report feeling tactile sensations based on visualization of the touch, without any actual physical contact. This effect is not only interesting for studies of human perception, but can also be leveraged to improve the quality of VR by evoking tactile sensations without usage of specialized equipment. The aim of this paper is to study brain processing of the illusory touch and its enhancement for purposes of exploitation in VR scene design. To amplify the illusory touch, transcranial direct current stimulation (tDCS) was used. Participants attended two sessions with blinded stimulation and interacted with a virtual ball using tracked hands in VR. The effects were studied using electroencephalography (EEG), that allowed us to examine stimulation-induced changes in processing of the illusory touch in the brain, as well as to identify its neural correlates. Results confirm enhanced processing of the illusory touch after the stimulation, and some of these changes were correlated to subjective rating of its magnitude.