Sleep deprivation (SD) can alter extrinsic, task-related fMRI signal involved in attention, memory and executive function. However, its effects on intrinsic low-frequency connectivity within the Default Mode Network (DMN) and its related anti-correlated network (ACN) have not been well characterized. We investigated the effect of SD on functional connectivity within the DMN, and on DMN-ACN...
The study of human brain electrophysiology has extended beyond traditional frequency ranges identified by the classical EEG rhythms, encompassing both higher and lower frequencies. Changes in high-gamma-band (>70 Hz) power have been identified as markers of local cortical activity. Fluctuations at infra-slow (<0.1 Hz) frequencies have been associated with functionally significant cortical...
PsychopharmacologyJuly 2011Jody Tanabe, Eric Nyberg, Laura F Martin et al.
The default mode network (DMN), one of several resting-state networks (RSN) in the brain, is thought to be involved in self-referential thought, awareness, and episodic memories. Nicotine improves cognitive performance, in part by improving attention. Nicotinic agonists have been shown to decrease activity in regions within DMN and increase activity in regions involved in visual attention...
Alzheimer s & DementiaJuly 1, 2011Márcio Luiz Figueredo Balthazar, Tátila Martins Lopes, Ana Carolina Coan et al.
Dysfunction of brain's Default Mode Network (DMN) has been increasingly described in patients with neurodegenerative diseases, but little is known about DMN's intrinsic functional connectivity (IFC) in Posterior Cortical Dysfunction (PCD) syndrome. We report a 56 year-old woman with PCD syndrome (MMSE = 24, CDR = 0.5) with visuospatial and anxiety complaints, confirmed by neuropsychological...
The default mode network (DMN) has been principally investigated using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) and has received mixed support in electroencephalographic (EEG) studies. In particular, the existing evidence is too inconsistent to allow formulation of specific hypotheses linking DMN activity to traditional EEG frequency bands. In this...
The default mode network (DMN) is a functional network which is implicated in a range of cognitive processes. This network is proposed to consist of hubs located in the ventromedial prefrontal cortex (vmPFC), posterior cingulate/retrosplenial cortex (PCC/rSpl), and inferior parietal lobule (IPL), with other midline cortical and temporal lobe nodes connected to these hubs. How this network is...
Although blind people heavily depend on working memory to manage daily life without visual information, it is not clear yet whether their working memory processing involves functional reorganization of the memory-related cortical network. To explore functional reorganization of the cortical network that supports various types of working memory processes in the early blind, we investigated...
The ability to generate and sustain an internal train of thought unrelated to external reality frees an agent from the constraints of only acting on immediate, environmentally triggered events. The current paper proposes that such thought is produced through cooperation between autobiographical information provided by the default mode network and a frontal-parietal control network which helps...
The engagement of the brain’s default mode network (DMN) may be compromised in attention deficit/hyperactivity disorder (ADHD) and one mechanism by which medication has its beneficial effects may be through modulation of this network. Liddle and colleagues in the current issue of the Journal (Liddle et al. , 2011) now show that motivation can modulate the effects of methylphenidate in ADHD via...
The default mode network (DMN) is often considered a functionally homogeneous system that is broadly associated with internally directed cognition (e.g., episodic memory, theory of mind, self-evaluation). However, few studies have examined how this network interacts with other networks during putative "default" processes such as episodic memory retrieval. Using functional magnetic resonance...