Multisensory integration in Peripersonal Space indexes consciousness states in sleep and disorders of consciousness
bioRxiv – October 25, 2024
Source: medRxiv/bioRxiv/arXiv
Summary
Did you know that our awareness of the world around us is closely tied to how our brain processes sensory information about our body? Researchers discovered a neural marker linked to this process, revealing that multisensory integration in our immediate space can indicate conscious states. Using EEG, they found this marker present during dreams and conscious wakefulness but absent in unconscious states. Remarkably, it also predicted recovery outcomes in patients with consciousness disorders, highlighting its potential as a key indicator of conscious experience.
Abstract
Conscious experience encompasses not only the awareness of external objects, but also a phenomenal representation of the embodied subject of the experience. The latter is mediated by the integration of multisensory stimuli between the body and the environment, a process mediated by the Peripersonal Space (PPS) system. Here we thus tested the hypothesis that a neural marker of PPS representation may index the presence of conscious experience. Using high-density EEG in awake participants, we identified a “PPS index”, characterized by high-beta oscillations in centroparietal regions during the integration of audiotactile stimuli presented near versus far from the body. We then examined this marker across two models of altered consciousness, i.e., sleep and disorders of consciousness. The PPS index persisted during dreaming and waking conscious states but was absent during dreamless, unconscious states. Moreover, the same index predicted behavioural measures of consciousness and clinical outcome in patients recovering from disorders of consciousness. These results suggest that multisensory integration within the PPS is tightly linked to the presence of conscious experience.