Distinct Interactions between Fronto-Parietal and Default Mode Networks in Impaired Consciousness

Abstract

Existing evidence suggests that the default-mode network (DMN) and fronto-pariatal network (FPN) play an important role in altered states of consciousness. However, the brain mechanisms underlying impaired consciousness and the specific network interactions involved are not well understood. We studied the topological properties of brain functional networks using resting-state functional MRI data acquired from 18 patients (11 vegetative state/unresponsive wakefulness syndrome, VS/UWS, and 7 minimally conscious state, MCS) and compared these properties with those of healthy controls. We identified that the topological properties in DMN and FPN are anti-correlated which comes, in part, from the contribution of interactions between dorsolateral prefrontal cortex of the FPN and precuneus of the DMN. Notably, altered nodal connectivity strength was distance-dependent, with most disruptions appearing in long-distance connections within the FPN but in short-distance connections within the DMN. A multivariate pattern-classification analysis revealed that combination of topological patterns between the FPN and DMN could predict conscious state more effectively than connectivity within either network. Taken together, our results imply distinct interactions between the FPN and DMN, which may mediate conscious state.

Restoration of thalamo‐cortical connectivity after brain injury: recovery of consciousness, complex behavior, or passage of time?

“…In addition, we also found that over the first 6 months post‐injury, patients demonstrate a significant restoration of the agonistic and (relatively) antagonistic balance between the so‐called default mode network, which overlaps with the putative internal awareness network, and the executive control network, which overlaps with the putative external awareness network. These findings are in keeping with much of the cross‐sectional literature in chronic disorders of consciousness (Demertzi et al, ; Long et al, ; Vanhaudenhuyse et al, ).…”

Developmental Maturation of the Precuneus as a Functional Core of the Default Mode Network

“…It is important to understand developmental changes in task-and rest-state connectivity, as altered connectivity has been reported for numerous psychological disorders (see Cohen, 2018;Greicius, 2008, for reviews). For example, a maturational lag in DMN-to-FPN connectivity has been associated with attention-deficit/hyperactivity disorder (Sripada, Kessler, & Angstadt, 2014), and abnormal resting-state functional connectivity between DMN and FPN has been found in patients with obsessive compulsive disorder (Stern, Fitzgerald, Welsh, Abelson, & Taylor, 2012) and with impaired consciousness (Long et al, 2016). Future work could investigate whether precuneus's task-and rest-based connectivity is altered in atypical development and whether any such deviations from typical connectivity development correspond to behavioral or psychological impairments.…”

Decreased integration of EEG source-space networks in disorders of consciousness

“…The first is the left precuneus, a key hub structure from the default mode network (DMN). The precuneus is engaged in self-related processing (Zhang and Chiang-shan, 2012), episodic memory (Ren et al, 2018), awareness and conscious information processing (Kjaer et al, 2001;Vogt and Laureys, 2005;Long et al, 2016). The second is a portion of the left orbitofrontal cortex, which is thought to encode predicted values of potential rewards (Gottfried et al, 2003).…”