Subjectivity of the Anomalous Sense of Self Is Represented in Gray Matter Volume in the Brain.

In 96 healthy adults, lower gray matter volume in the insular cortex was linked to greater reported malfunction in the sense of ownership over one's body, as measured by the Embodied Sense of Self Scale. No such relationship was found for the sense of agency or narrative self. This suggests that the feeling of ownership may rely on distinct brain structures, and the scale could help screen for such neural correlates.

Study at a glance

Abstract

The self includes complicated and heterogeneous functions. Researchers have divided the self into three distinct functions called "agency," "ownership," and "narrative self". These correspond to psychiatric symptoms, behavioral characteristics and neural responses, but their relationship with brain structure is unclear. This study examined the relationship between the subjectivity of self-related malfunctions and brain structure in terms of gray matter (GM) volume in 96 healthy people. They completed a recently developed self-reported questionnaire called the Embodied Sense of Self Scale (ESSS) that measures self-related malfunctions. The ESSS has three subscales reflecting the three distinct functions of the self. We also determined the participants' brain structures using magnetic resonance imaging (MRI) and voxel-based morphometry (VBM). Multiple regression analysis revealed a significant negative correlation between ownership malfunction and the insular cortex GM volume. A relationship with brain structure could thus only be confirmed for the ESSS "ownership" subscale. This finding suggests that distinct brain structures feel ownership and that the ESSS could partly screen for distinct brain structures.