Annual Review of Neuroscience
May 4, 2015
Marcus E. Raichle
4,082 citations
The brain's default mode network consists of discrete, bilateral, and symmetrical cortical areas found in humans, nonhuman primates, cats, and rodents. It was discovered unexpectedly through PET imaging when novel, attention-demanding tasks were compared with quiet rest. This network consistently decreases its activity during such tasks relative to relaxed states. Its discovery renewed interest in the brain's ongoing or intrinsic activity, and resting-state studies now play a major role in understanding the human brain in health and disease, with the default mode network central to this work.
Proceedings of the National Academy of Sciences
February 21, 2012
Hanbing Lu, Qihong Zou, Hong Gu et al.
627 citations
A brain network called the default mode network (DMN), previously studied mainly in humans and primates, also exists in rats. The DMN in rats is broadly similar to that in nonhuman primates and humans, suggesting it is a fundamental feature of mammalian brains. The network appears to integrate sensory and emotional information to guide behavior in anticipation of changing environmental conditions, despite the distinct evolutionary paths of rodents and primates. The findings help clarify the DMN's core functions, which remain poorly understood in humans.
Biological Psychiatry
October 15, 2009
Yvette I. Sheline, Marcus E. Raichle, Abraham Z. Snyder et al.
608 citations
Functional connections within the default mode network are disrupted in Alzheimer's disease, likely due to amyloid-beta plaque toxicity. In cognitively normal participants with preclinical amyloid deposition, resting-state fMRI revealed differences in functional connectivity between the precuneus and several brain regions—including the hippocampus, parahippocampus, and cingulate cortex—that matched the pattern seen in Alzheimer's disease patients. These findings suggest that early amyloid-beta toxicity can be detected with resting-state fMRI before any cognitive or behavioral changes appear.
medRxiv
August 24, 2023
Subha Subramanian, Demetrius Perry, Caterina Gratton et al.
14 citations
preprint
Psilocybin disrupts connectivity across cortical networks and subcortical structures, producing more than three-fold greater acute changes in functional networks than methylphenidate. These changes are driven by desynchronization of brain activity across spatial scales, strongest in the default mode network (DMN), which is connected to the anterior hippocampus and thought to create our sense of self. Performing a perceptual task reduces psilocybin-induced network changes, suggesting a neurobiological basis for grounding during psychedelic therapy. Psilocybin induces a persistent decrease in functional connectivity between the anterior hippocampus and cortex (and DMN in particular), lasting for weeks but normalizing after six months. This persistent suppression of hippocampal-DMN connectivity represents a candidate neuroanatomical and mechanistic correlate for psilocybin's pro-plasticity and anti-depressant effects.
Advances in Consciousness Research
October 28, 2010
Biyu J. He, Marcus E. Raichle
A neurophysiological hypothesis proposes that the slow cortical potential (SCP) recorded from the brain's surface reflects the activity of superficial-layer pyramidal neurons, which directly contribute to conscious awareness. Existing data from manipulations of conscious awareness in normal subjects, as well as from altered states like general anesthesia and recovery from vegetative states, support this idea. The hypothesis also makes experimentally testable predictions. Because a relationship between the SCP and fMRI signals has been identified, this hypothesis may bridge neuroimaging and electrophysiological studies of consciousness.