Grid cell activity in entorhinal cortex reflects self-consciousness

Grid cells in the entorhinal cortex (EC) encode an individual’s location in space, integrating both environmental and multisensory bodily cues. However, body-derived signals are also primary signals for the sense of self. While studies have demonstrated that continuous application of visuo-tactile bodily stimuli can induce perceptual shifts in self-consciousness (i.e., self-location), it remains unexplored whether these illusory changes in self-location suffice to trigger grid cell–like representation (GCLR) within the EC, and how this compares to GCLR during conventional virtual navigation.

To address this, we systematically induced illusory drifts in self-location toward controlled directions using visuo-tactile bodily stimulation, achieved by a new MRI setup based on immersive virtual reality and motion tracking during fMRI acquisition. Subsequently, we evaluated the corresponding GCLR in the EC through functional MRI analysis.

Moon et al. reveal that illusory changes in perceived self-location (independent of changes in environmental navigation cues) evokes entorhinal GCLR, correlating in strength with the magnitude of perceived self-location, and characterized by similar grid orientation as during conventional virtual navigation in the same virtual room. These data demonstrate that the same grid-like representation is recruited when navigating based on environmental, mainly visual cues, or when experiencing pure illusory drifts in self-location, driven by perceptual multisensory bodily cues. Extending previous data from our group (Moon et al., 2022), these findings provide robust evidence that grid cells in entorhinal cortex represent the self in space rather than merely the body in space and provide important starting points to investigate interactions between spatial navigation and self-consciousness that may be of relevance for the early detection of neurodegenerative disorders such as Alzheimer’s disease (Kunz et al., 2015).