Functional-Anatomic Fractionation of the Brain's Default Network

Abstract

Summary One of the most consistent observations in human functional imaging is that a network of brain regions referred to as the “default network” increases its activity during passive states. Here we explored the anatomy and function of the default network across three studies to resolve divergent hypotheses about its contributions to spontaneous thought and active forms of decision-making. Analysis of intrinsic activity revealed the network comprises multiple, dissociated components. A midline core (posterior cingulate and anterior medial prefrontal cortex) is active when people make self-relevant, affective decisions. In contrast, a medial temporal lobe subsystem becomes engaged when decisions involve constructing a mental scene based on memory. During certain experimentally-directed and spontaneous acts of future-oriented thought, these dissociated components are simultaneously engaged presumably to facilitate construction of mental models of personally-significant events.

Dissociable relations between amygdala subregional networks and psychopathy trait dimensions in conduct‐disordered juvenile offenders

“…Notwithstanding their myriad functions, these interconnected cortical regions seem to serve as key nodes within the so‐called default mode network (DMN), whose network function putatively supports internally and externally directed sociocognitive processes [Andrews‐Hanna et al, 2010; Li et al, 2014]. Though the CMA is not part of the canonical DMN, it is in close contact with core DMN regions (both functionally and structurally) [Bienkowski and Rinaman, 2013; Bzdok et al, 2013; Keifer et al, 2015; Pessoa, 2011; Sah et al, 2003], and may as such impact its network function.…”

“…Echoing earlier work on amygdala subregional networks and their dissociable relations with psychopathy trait dimensions [Yoder et al, 2015], we hypothesized that both BLA and CMA connectivity would relate to the interpersonal dimension of psychopathy, while its affective dimension would relate primarily to CMA and its behavioral dimension primarily to BLA connectivity. Specifically, as interpersonal traits index a self‐centered, manipulative, and reward‐oriented interaction style [Andershed et al, 2007; Cooke and Michie, 2001; Neumann et al, 2006; Seara‐Cardoso and Viding, 2014], we speculated that these traits would relate to BLA and CMA connectivity with regions supporting sociocognitive [Andrews‐Hanna et al, 2010; Li et al, 2014] and reward‐related [Haber, 2011; Naqvi and Bechara, 2009] processes. In contrast, as affective psychopathic traits index callousness and lack of negative emotionality [Andershed et al, 2007; Cooke and Michie, 2001; Neumann et al, 2006; Seara‐Cardoso and Viding, 2014], it may seem reasonable to assume an association between these traits and connectivity of CMA with regions serving affective saliency and emotional responding [Etkin et al, 2011; Pessoa, 2011; Seeley et al, 2007].…”

Cognitive reserve impacts on inter-individual variability in resting-state cerebral metabolism in normal aging

“…The default mode network comprises two distinct subsystems that interact with a midline core (Andrews-Hanna, Reidler, Sepulcre, Poulin, & Buckner, 2010;Buckner, Andrews-Hanna, & Schacter, 2008). The medial temporal lobe (MTL) subsystem includes the hippocampus, the parahippocampal cortex, the ventral medial prefrontal cortex, the posterior inferior parietal lobule and the retrosplenial cortex.…”

EEG microstates as a tool for studying the temporal dynamics of whole-brain neuronal networks: A review

“…Xu and colleagues (Xu et al, 2016) demonstrated that the anterior regions of the default mode network are associated with selfreferential mental thoughts, while the posterior regions are associated with episodic memory retrieval. Similarly, Andrews-Hanna and colleagues reported that the dorsal medial cortex subsystem of the default mode network is responsible for internally guided cognition, while the medial temporal subsystem is responsible for memory-guided imagery (Andrews-Hanna, 2012;Andrews-Hanna et al, 2010). These findings suggest that, if such a distinction of the default mode network had been used in , microstate C would have been associated with the anterior default mode network, rather than the salience network.…”