The default mode network (DMN) refers to regional brain activity that is greater during rest periods than during attention-demanding tasks; many studies have reported DMN alterations in patient populations. It has also been shown that the DMN is suppressed by scanner background noise (SBN), which is the noise produced by functional magnetic resonance imaging (fMRI). However, it is unclear...
Areas associated with the default mode network (DMN) are substantially similar to those associated with meditation practice. However, no studies on DMN connectivity during resting states have been conducted on meditation practitioners. It was hypothesized that meditators would show heightened functional connectivity in areas of cortical midline activity. Thirty-five meditation practitioners and...
Episodic memories can be retrieved by an intentional search for certain information. Alternatively, a past episode may enter our consciousness without any intention to retrieve it, prompted by a stimulus in our surroundings. Incidental retrieval does not occur upon each encounter with a familiar stimulus, suggesting that a gating mechanism exists which regulates incidental retrieval activity....
Objective: To describe the neuroanatomical correlations of an isolated lesion in the anterior thalamus using functional imaging in a 40-year-old man with multiple sclerosis. Design: Case report with 10 cognitively normal controls. Setting: Mayo Clinic, Rochester, Minnesota. Patient: A 40-year-old man with a 2-week course of acute-onset amnesia, abulia, poor concentration, hypersomnolence, and...
ObjectiveThe choice of electroencephalograph (EEG) reference is a critical issue for the study of brain activity. The present study addressed the use of the infinity reference obtained by the reference electrode standardisation technique (REST) in the study of EEG default mode network (DMN).MethodsA total of 100 randomly positioned source configurations, each consisting of two dipoles with...
The last two decades have witnessed great progress in mapping neural networks associated with task-induced brain activation. More recently, identification of resting state networks (RSN) paved the way to investigate spontaneous task-unrelated brain activity. The cardinal features characterising RSN are low-frequency fluctuations of blood oxygenation level dependent (BOLD) signals synchronised...
Functional neuroimaging studies provide converging evidence for existence of intrinsic brain networks activated during resting states and deactivated with selective cognitive demands. Whether task-related deactivation of the default mode network signifies depressed activity relative to the remaining brain or simply lower activity relative to its resting state remains controversial. We employed...
Functional and structural maturation of networks comprised of discrete regions is an important aspect of brain development. The default-mode network (DMN) is a prominent network which includes the posterior cingulate cortex (PCC), medial prefrontal cortex (mPFC), medial temporal lobes (MTL), and angular gyrus (AG). Despite increasing interest in DMN function, little is known about its...
Unlabelled: Functional MRI (fMRI) of default mode network (DMN) brain activity during resting state is gaining attention as a potential non-invasive biomarker to diagnose incipient Alzheimer's disease. The aim of this study was to identify effects of normal aging on the DMN using different methods of fMRI processing and evaluation. Methods: fMRI was acquired in 17 young and 21 old healthy...
Introduction: A "resting state" or "default mode network" has been highlighted in functional neuroimaging studies as a set of brain regions showing synchronized activity at rest or in task-independent cognitive state. State of the art: A considerable and increasing number of studies have been conducted over the last few years so as to unravel the cognitive function(s) of this brain network....