The default mode network and social understanding of others: what do brain connectivity studies tell us

Abstract

The Default Mode Network (DMN) has been found to be involved in various domains of cognitive and social processing. The present article will review brain connectivity results related to the DMN in the fields of social understanding of others: emotion perception, empathy, theory of mind, and morality. Most of the reviewed studies focused on healthy subjects with no neurological and psychiatric disease, but some studies on patients with autism and psychopathy will also be discussed. Common results show that the medial prefrontal cortex (MPFC) plays a key role in the social understanding of others, and the subregions of the MPFC contribute differently to this function according to their roles in different subsystems of the DMN. At the bottom, the ventral MPFC in the medial temporal lobe (MTL) subsystem and its connections with emotion regions are mainly associated with emotion engagement during social interactions. Above, the anterior MPFC (aMPFC) in the cortical midline structures (CMS) and its connections with posterior and anterior cingulate cortex contribute mostly to making self-other distinctions. At the top, the dorsal MPFC (dMPFC) in the dMPFC subsystem and its connection with the temporo-parietal junction (TPJ) are primarily related to the understanding of other's mental states. As behaviors become more complex, the related regions in frontal cortex are located higher. This reflects the transfer of information processing from automatic to cognitive processes with the increase of the complexity of social interaction. Besides the MPFC and TPJ, the connectivities of posterior cingulate cortex (PCC) also show some changes during tasks from the four social fields. These results indicate that the DMN is indispensable in the social understanding of others.

Electrophysiological evidence during episodic prospection implicates medial prefrontal and bilateral middle temporal gyrus

“…Functional magnetic resonance imaging (fMRI) studies have implicated the medial prefrontal cortex and medial temporal lobe as a putative neural network underpinning episodic prospection (Buckner, Andrews-Hanna, & Schacter, 2008) working with MPFC and MTG to facilitate processes of self-projection into the future (Bar, 2009;Buckner & Carroll, 2007). This is consistent with the research showing that MTG provides the foundation for internal mentation during autobiographical memory retrieval (Fox, Spreng, Ellamil, Andrews-Hanna, & Christoff, 2015;Li, Mai, & Liu, 2014;Tulving, 2002), while MPFC is implicated in self-related simulations (Kim, 2012;Szpunar, Watson, & McDermott, 2007) and complex perspective-taking processes (Van Hoeck et al, 2013).…”

Reduced Default Mode Connectivity in Adolescents With Conduct Disorder

“…2 morality judgments 13,14 . The MTL subsystem is involved in binding together disparate information to facilitate scene construction 8 and the aMPFC-PCC core in attaching personal significance to internally focused thoughts 8 as well as forming the self-other distinctions linked to pro-social behavior 15 and possibly judgments of affective empathy 16 .…”

Functional SPECT neuroimaging using machine learning algorithms distinguishes autism spectrum disorder from healthy subjects

“…Prior literature has shown the right temporal parietal junction is an associative region and has been shown to respond atypically in those with autism spectrum conditions [64]. This region has been implicated in the understanding of the "theory of mind, " [65] language, spatial cognition and attention that is implicated in the social-communication deficits observed in ASD. Furthermore, the amygdala was identified as a distinguishing feature.…”