John Libbey Eurotext

Revue de neuropsychologie

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The default mode network: a resting-state that does not rest Volume 10, issue 3, Juillet-Août-Septembre 2018

Figures

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Author
1 Liège université,
GIGA – Centre de recherches du Cyclotron « in vivo imaging »,
quartier Agora,
allée du 6-Août, 8, B30,
4000 Liège,
Belgique
2 Fonds national de la recherche scientifique (FRS),
1000 Bruxelles, Belgique
* Correspondance
  • Key words: neuroimaging, default mode network, functional connectivity, cognition, Alzheimer's disease
  • DOI : 10.1684/nrp.2018.0469
  • Page(s) : 232-8
  • Published in: 2018

Neuroimaging studies contrasting brain activity during tasks versus rest revealed that a set a brain regions is systematically more active during rest than during tasks. Considering that this reflects the basic and continuously active state of the brain when one is not engaged in attention-demanding tasks, this brain network has been termed as the default mode network. Currently, the default mode network is mostly studied by functional connectivity analyses during resting-state functional MRI, whereby regions showing correlated activity over time are identified. It includes the posterior cingulate cortex, the precuneus, the medial prefrontal cortex, the inferior parietal cortex and the medial temporal lobe. Different approaches have explored the cognitive correlates of the default mode network. First, neuroimaging studies indicated that regions from the default mode network are activated by specific cognitive tasks, including successful retrieval in episodic memory, autobiographical memory, future thinking, self-referential processing and theory of mind. Second, investigations of the mental content of individuals while they are resting revealed that most of the mental experience during rest consists in internally-oriented self-generated thoughts, such as autobiographical reminiscence, planning future events and reflecting about oneself and others. Third, correlational studies showed that individuals with more active or better-connected default mode network have better memory or more frequent mind wandering. Integrating these observations, the internal cognition hypothesis proposes that the default mode network has an adaptive role by which the brain uses past experiences to simulate possible future scenarios in order to prepare individuals to react to upcoming events. Alternatively, it has been suggested that the default mode network's function goes beyond consciousness and would rather coordinate intrinsic activity of cerebral systems to facilitate processing of any incoming information. The central role of the default mode network is exemplified by the fact that it is vulnerable to several psychopathological and health-related conditions.