Binding the Self

Purpose and goal:

Binding the Self showed that cortical oscillations temporally integrate different sensory stimuli into a multisensory representation of the physical self to generate the sense of body ownership, i.e., the experience of one´s body as one´s own. We clarified that temporal resolution of perception reflects multisensory integration involved in body ownership.

We demonstrated the role of alpha frequency in integrating visuotactile signals to generate the sense of body ownership, using both correlational (Electroencephalography) and casual (brain stimulation) approaches Expected results and effects:

Results showed that temporal resolution of visuotactile and proprio-tactile integration correlates with multisensory integration involved in body ownership, when body ownership is induced both by visuo-tactile information or only by proprio-tactile stimuli, without vision. Using both electroencephalography and brain stimulation we showed that parietal alpha frequency temporally integrates visutactile stimuli into a multisensory representation of the bodily self. A current study is investigating if beta frequency equally integrates proprio-tactile stimuli.

Approach and implementation:

To compute the synchronicity threshold in the RHI and SJT, we used a psychophysical task developed in the lab, where taps are applied to a fake hand and to the participants’ hand, either synch or at different delays. Participants performed body ownership and synchronicity judgments. The synchronicity threshold was correlated between tasks (Exp 1) and individual alpha frequency (Exp 2).

To test the causal role of alpha frequency, we used transcranial alternating current stimulation (tACS) to modulate alpha frequency and, accordingly, the synchronicity threshold (Exp 3).