Neuroimage
May 1, 2021
Pengmin Qin, Xuehai Wu, Changwei W Wu et al.
51 citations
Consciousness depends on a network of brain regions that integrate sensory and motor information. Analyzing fMRI data from people in preserved (awake, fully conscious brain-injury survivors), reduced (N1-sleep, minimally conscious), and lost (N3-sleep, anesthesia, unresponsive wakefulness) states, plus a unique rapid-eye-movement (REM) sleep group, researchers identified key hubs whose degree centrality—a measure of network importance—dropped significantly when consciousness was reduced or absent. These hubs included the supplementary motor area, bilateral supramarginal gyrus, supragenual/dorsal anterior cingulate cortex, and left middle temporal gyrus. A higher-order sensorimotor circuit connecting these regions showed functional connectivity that correlated with consciousness levels across groups and remained active in REM sleep, suggesting this circuit supports consciousness and offers new targets for treating disorders of consciousness.
Frontiers in Psychology
August 6, 2018
Stuart Fogel, L. Bryan Ray, Valya Sergeeva et al.
37 citations
The extent to which newly learned material is incorporated into dreams is related to individual differences in cognitive abilities. Using a computational linguistic approach to measure semantic similarity between waking experiences and dream reports, the study found that the richness of incorporation of a spatial or motor memory task into early hypnagogic dreams correlated with reasoning abilities (r=0.41), while incorporation into later dreams correlated with verbal abilities (r=0.46). Memory performance improvements were related to dream incorporation (r=0.47) for early but not late dreams, but this relationship was not mediated by cognitive abilities, suggesting a direct link between reasoning and dream incorporation.
Scientific Reports
June 7, 2021
Evan Houldin, Zhuo Fang, Laura B Ray et al.
17 citations
During sleep, functional connections between brain networks shift in a directional manner. In non-REM (NREM) sleep, positive wake-like correlations often become negative and strengthen in the opposite direction, while in REM sleep they trend back toward positive correlations. This pattern supports the idea that NREM sleep involves altered, not merely reduced, functional connectivity. Many of these connections involve higher-order networks linked to cognition and consciousness, such as the default mode network, suggesting possible accompanying changes in cognitive and conscious states.
Neuroscience and Biobehavioral Reviews
May 1, 2023
Georg Northoff, Andrea Scalabrini, Stuart Fogel
13 citations
Dreams occupy a bizarre and poorly understood state of consciousness. The Topographic-dynamic Re-organization model (TRoD) proposes that dreaming involves a shift toward increased activity and connectivity in the default-mode network (DMN) alongside reduced activity in the central executive network, except during lucid dreaming. Dynamically, dreams shift toward slower brain frequencies and longer timescales, placing them between wakefulness and NREM stage 2 or slow-wave sleep. This re-organization produces abnormal spatiotemporal processing of internal and external inputs, moving from temporal segregation to integration. The resulting integration yields bizarre, self-centric mental content and hallucinatory-like states, suggesting that topography and temporal dynamics may serve as a common currency linking brain activity to dream experience.