Common and distinct brain networks of autoscopic phenomena

Abstract

Objective: Autoscopic phenomena (AP) are illusory own body reduplications characterized by the visual perception of a second own body in extrapersonal space, and include three main forms: autoscopic hallucination (AH), heautoscopy (HAS) and out-of-body-experience (OBE). Past research showed that lesions were heterogeneously distributed and affected many different brain regions within and across patients, while small case series suggested that AP lesions converge in temporo-parietal and parieto-occipital cortex. As only few studies investigated each form of AP separately, it remains unknown whether the three AP are characterized by common and distinct brain mechanisms.

Methods: Here, we applied lesion network analysis in 26 neurological AP patients and determined their common and distinct functional connectivity patterns.

Results: We report that all localize to a single common brain network at the bilateral temporo-parietal junction, further associated with specific patterns of functional connectivity, defining each type of AP. OBE resulted from a brain network connected to bilateral angular gyrus, right precuneus, and right inferior frontal gyrus, differing from AH with a brain network connected to bilateral precuneus, inferior temporal gyrus, and cerebellum. HAS resulted from a brain network connected to left inferior frontal gyrus, left insula and left parahippocampus.

Conclusion: The present data identify the temporo-parietal junction as the common core region for AP and show that each form of AP recruits additional specific networks, associated with different sensorimotor and self-related sub-networks.

Keywords: Bodily self-consciousness; Lesion network mapping; Multisensory processing; Temporo-parietal junction.

Fig. 1

Autoscopic phenomena (AP). Phenomenology of the different AP: autoscopic hallucination (A), heautoscopy (B) and out-of-body experience (C). A. During AH, patients report seeing an autoscopic body in extrapersonal space from their habitual body-centered self-location and perspective (indicated by Self). B. During HAS, patients report alternating self-location and first-person perspective between the physical body and the autoscopic body. C. In OBE, patients report disembodiment (i.e. the experience of being located outside the physical body) and to be located with an elevated position and perspective. Self in each depiction represents experienced self-location and the arrow represents the experienced direction of the first-person perspective, for each AP separately (for more detail see main text). The grey body represents the location of the illusory autoscopic body.

Fig. 2

Lesion derived network for each AP. Brain networks connected to lesions causing autoscopic hallucinations (AH) (A), heautoscopy (HAS) (B) and out-of-body experiences (OBE) (C). Brain networks for each AP are depicted in red. The yellow regions indicate those brain regions that are specific for each AP as compared to the other two AP (Liebermeister test; see methods and results for further detail). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Overlap of all three AP networks. The brain networks of each AP were overlap and displayed onto a common template brain to reveal common and distinct network components. AH is shown in green, OBE in blue and HAS in light green. Shared brain networks were observed between HAS and OBE (overlap indicated in light blue) in the temporo-parietal junction. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 4

Common AP brain regions. 90% of the lesions causing AP were connected to a brain network including bilateral temporo-parietal junction (in bilateral pMTG and right STG) as well as in smaller bilateral clusters in the hippocampus/parahippocampus.