Self-Referential Processing Effects of Non-invasive Brain Stimulation: A Systematic Review.

Zhongjie Bao,Amer M Burhan,Paul Frewen,Belal Howidi

doi:10.3389/fnins.2021.671020

Abstract

Systematic reviews of neuroimaging studies confirm stimulus-induced activity in response to verbal and non-verbal self-referential processing (SRP) in cortical midline structures, temporoparietal cortex and insula. Whether SRP can be causally modulated by way of non-invasive brain stimulation (NIBS) has also been investigated in several studies. Here we summarize the NIBS literature including 27 studies of task-based SRP comparing response between verbal and non-verbal SRP tasks. The studies differed in design, experimental tasks and stimulation parameters. Results support the role of left inferior parietal lobule (left IPL) in verbal SRP and for the medial prefrontal cortex when valenced stimuli were used. Further, results support roles for the bilateral parietal lobe (IPL, posterior cingulate cortex), the sensorimotor areas (the primary sensory and motor cortex, the premotor cortex, and the extrastriate body area) and the insula in non-verbal SRP (bodily self-consciousness). We conclude that NIBS may differentially modulate verbal and non-verbal SRP by targeting the corresponding brain areas.

Highlights

What constitutes our sense of self? This question has intrigued philosophers, psychologists, and neuroscientists alike for centuries
Neuroimaging reviews suggested that self-referential processing (SRP) in general may be associated with activities in the default mode network (DMN) and its sub-systems
Within the DMN, the dorsomedial prefrontal cortex (DMPFC) subsystem consists of the DMPFC, inferior parietal lobule (IPL), the lateral temporal cortex, and the temporal poles, whereas the medial temporal lobe (MTL) subsystem consists of the ventromedial prefrontal cortex (VMPFC), posterior IPL, the retrosplenial cortex and the hippocampus, and the midline core subsystem can

Summary

Introduction

What constitutes our sense of self? This question has intrigued philosophers, psychologists, and neuroscientists alike for centuries. The distinction between verbal SRP (VSRP) and non-verbal SRP (NV-SRP) bears significance in recent research topics (Frewen et al, 2020), including psychopathology (LeMoult et al, 2017; Lin et al, 2018; Yoon et al, 2019), neuroendocrinology (Li et al, 2018; van Buuren et al, 2020), and meditation (Katyal et al, 2020). Researchers have taken interest in the neurobiological basis of V-SRP and NV-SRP, with neuroimaging literature providing a basis for distinguishing SRP into verbal (V-SRP) versus non-verbal (NV-SRP) domains (Frewen et al, 2020). Within the DMN, the dorsomedial prefrontal cortex (DMPFC) subsystem consists of the DMPFC, inferior parietal lobule (IPL), the lateral temporal cortex, and the temporal poles, whereas the medial temporal lobe (MTL) subsystem consists of the ventromedial prefrontal cortex (VMPFC), posterior IPL, the retrosplenial cortex and the hippocampus, and the midline core subsystem can

Methods

Results

Conclusion