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"default network"

Janice Chen, Yuan Chang Leong, Christopher J Honey, Chung H Yong, Kenneth A Norman, Uri Hasson
Our lives revolve around sharing experiences and memories with others. When different people recount the same events, how similar are their underlying neural representations? Participants viewed a 50-min movie, then verbally described the events during functional MRI, producing unguided detailed descriptions lasting up to 40 min. As each person spoke, event-specific spatial patterns were reinstated in default-network, medial-temporal, and high-level visual areas. Individual event patterns were both highly discriminable from one another and similar among people, suggesting consistent spatial organization...
December 5, 2016: Nature Neuroscience
Omar Mothersill, Noreen Tangney, Derek W Morris, Hazel McCarthy, Thomas Frodl, Michael Gill, Aiden Corvin, Gary Donohoe
BACKGROUND: Resting-state functional magnetic resonance imaging (rs-fMRI) has repeatedly shown evidence of altered functional connectivity of large-scale networks in schizophrenia. The relationship between these connectivity changes and behaviour (e.g. symptoms, neuropsychological performance) remains unclear. METHODS: Functional connectivity in 27 patients with schizophrenia or schizoaffective disorder, and 25 age and gender matched healthy controls was examined using rs-fMRI...
November 29, 2016: Schizophrenia Research
Zhuqing Jiao, Kai Ma, Huan Wang, Ling Zou, Jianbo Xiang
The aim of this study is to introduce Hamiltonian path to analyze functional connectivity of brain default mode networks (DMNs). Firstly, the brain DMNs in resting state are constructed with the employment of functional Magnetic Resonance Imaging (fMRI) data. Then, the Dijkstra algorithm is used to calculate the shortest path length of the node which represents each brain region, and the Hamiltonian path of the default network is solved through the improved adaptive ant colony algorithm. Finally, complex network analysis methods are introduced to discuss the node and network properties of brain functional connectivity in both normal subjects and stroke patients...
November 24, 2016: CNS & Neurological Disorders Drug Targets
Rémi Radel, Jeanick Brisswalter, Stéphane Perrey
Executive functioning and attention require mental effort. In line with the resource conservation principle, we hypothesized that mental effort would be saved when individuals expected to exercise for a long period. Twenty-two study participants exercised twice on a cycle ergometer for 10 min at 60% of their maximal aerobic power, with the expectation of exercising for either 10 min or 60 min. Changes in activity in the right dorsolateral prefrontal cortex (rdlPFC) and right medial frontal cortex (rmPFC) were investigated by measuring oxyhemoglobin using near-infrared spectroscopy...
November 17, 2016: Cognitive, Affective & Behavioral Neuroscience
Aaron Kucyi, Michael Esterman, Clay S Riley, Eve M Valera
The brain's default mode network (DMN) is highly active during wakeful rest when people are not overtly engaged with a sensory stimulus or externally oriented task. In multiple contexts, increased spontaneous DMN activity has been associated with self-reported episodes of mind-wandering, or thoughts that are unrelated to the present sensory environment. Mind-wandering characterizes much of waking life and is often associated with error-prone, variable behavior. However, increased spontaneous DMN activity has also been reliably associated with stable, rather than variable, behavior...
November 29, 2016: Proceedings of the National Academy of Sciences of the United States of America
Amalia R McDonald, Jordan Muraskin, Nicholas T Van Dam, Caroline Froehlich, Benjamin Puccio, John Pellman, Clemens C C Bauer, Alexis Akeyson, Melissa M Breland, Vince D Calhoun, Steven Carter, Tiffany P Chang, Chelsea Gessner, Alyssa Gianonne, Steven Giavasis, Jamie Glass, Steven Homann, Margaret King, Melissa Kramer, Drew Landis, Alexis Lieval, Jonathan Lisinski, Anna Mackay-Brandt, Brittny Miller, Laura Panek, Hayley Reed, Christine Santiago, Eszter Schoell, Richard Sinnig, Melissa Sital, Elise Taverna, Russell Tobe, Kristin Trautman, Betty Varghese, Lauren Walden, Runtang Wang, Abigail B Waters, Dylan C Wood, F Xavier Castellanos, Bennett Leventhal, Stanley J Colcombe, Stephen LaConte, Michael P Milham, R Cameron Craddock
This data descriptor describes a repository of openly shared data from an experiment to assess inter-individual differences in default mode network (DMN) activity. This repository includes cross-sectional functional magnetic resonance imaging (fMRI) data from the Multi Source Interference Task, to assess DMN deactivation, the Moral Dilemma Task, to assess DMN activation, a resting state fMRI scan, and a DMN neurofeedback paradigm, to assess DMN modulation, along with accompanying behavioral and cognitive measures...
November 9, 2016: NeuroImage
Benjamin W Mooneyham, Michael D Mrazek, Alissa J Mrazek, Kaita L Mrazek, Dawa T Phillips, Jonathan W Schooler
During tasks that require continuous engagement, the mind alternates between mental states of focused attention and mind-wandering. Existing research has assessed the functional connectivity of intrinsic brain networks underlying the experience and training of these mental states using "static" approaches that assess connectivity across an entire task. To disentangle the functional connectivity between brain regions as the mind fluctuates between discrete brain states, we employed a dynamic functional connectivity approach that characterized brain activity using a sliding window...
October 25, 2016: Journal of Cognitive Neuroscience
Elisa C K Steinfurth, Manuela G Alius, Julia Wendt, Alfons O Hamm
The current experiments tested neural and physiological correlates of worry and rumination in comparison to thinking about neutral events. According to the avoidance model-stating that worry is a strategy to reduce intense emotions-physiological and neurobiological activity during worried thinking should not differ from activation during neutral thinking. According to the contrast avoidance model-stating that worry is a strategy to reduce abrupt shifts of emotions-activity should be increased. To test these competing models, we induced worry and neutral thinking in healthy participants using personal topics...
October 21, 2016: Psychophysiology
Antonello Baldassarre, Lenny E Ramsey, Joshua S Siegel, Gordon L Shulman, Maurizio Corbetta
PURPOSE OF REVIEW: An important challenge in neurology is identifying the neural mechanisms underlying behavioral deficits after brain injury. Here, we review recent advances in understanding the effects of focal brain lesions on brain networks and behavior. RECENT FINDINGS: Neuroimaging studies indicate that the human brain is organized in large-scale resting state networks (RSNs) defined via functional connectivity, that is the temporal correlation of spontaneous activity between different areas...
December 2016: Current Opinion in Neurology
Linda Douw, Daniel G Wakeman, Naoaki Tanaka, Hesheng Liu, Steven M Stufflebeam
The brain is a dynamic, flexible network that continuously reconfigures. However, the neural underpinnings of how state-dependent variability of dynamic functional connectivity (vdFC) relates to cognitive flexibility are unclear. We therefore investigated flexible functional connectivity during resting-state and task-state functional magnetic resonance imaging (rs-fMRI and t-fMRI, resp.) and performed separate, out-of-scanner neuropsychological testing. We hypothesize that state-dependent vdFC between the frontoparietal network (FPN) and the default mode network (DMN) relates to cognitive flexibility...
December 17, 2016: Neuroscience
Kieran C R Fox, Jessica R Andrews-Hanna, Kalina Christoff
Investigation of the neural basis of self-generated thought is moving beyond a simple identification with default network activation toward a more comprehensive view recognizing the role of the frontoparietal control network and other areas. A major task ahead is to unravel the functional roles and temporal dynamics of the widely distributed brain regions recruited during self-generated thought. We argue that various other neuroscientific methods - including lesion studies, human intracranial electrophysiology, and manipulation of neurochemistry - have much to contribute to this project...
October 29, 2016: Neuroscience
Aviva Berkovich-Ohana, Michal Harel, Avital Hahamy, Amos Arieli, Rafael Malach
FMRI data described here was recorded during resting-state in Mindfulness Meditators (MM) and control participants (see "Task-induced activity and resting-state fluctuations undergo similar alterations in visual and DMN areas of long-term meditators" Berkovich-Ohana et al. (2016) [1] for details). MM participants were also scanned during meditation. Analyses focused on functional connectivity within and between the default mode network (DMN) and visual network (Vis). Here we show data demonstrating that: 1) Functional connectivity within the DMN and the Visual networks were higher in the control group than in the meditators; 2) Data show an increase for the functional connectivity between the DMN and the Visual networks in the meditators compared to controls; 3) Data demonstrate that functional connectivity both within and between networks reduces during meditation, compared to the resting-state; and 4) A significant negative correlation was found between DMN functional connectivity and meditation expertise...
September 2016: Data in Brief
Justin S Lawley, Jamie H Macdonald, Samuel J Oliver, Paul G Mullins
Hypoxia causes an increase in global cerebral blood flow, which maintains global cerebral oxygen delivery and metabolism. Yet neurological deficits are abundant under hypoxic conditions. We investigated regional cerebral microvascular responses to acute (2 h) and prolonged (10 h) poikilocapnic normobaric hypoxia. We found that 2 h of hypoxia caused an expected increase in frontal cortical grey matter perfusion, but unexpected perfusion decreases in regions of the brain normally associated with the "default mode" or "task negative" network...
August 9, 2016: Journal of Physiology
Maria Luisa Mandelli, Eduard Vilaplana, Jesse A Brown, H Isabel Hubbard, Richard J Binney, Suneth Attygalle, Miguel A Santos-Santos, Zachary A Miller, Mikhail Pakvasa, Maya L Henry, Howard J Rosen, Roland G Henry, Gil D Rabinovici, Bruce L Miller, William W Seeley, Maria Luisa Gorno-Tempini
Neurodegeneration has been hypothesized to follow predetermined large-scale networks through the trans-synaptic spread of toxic proteins from a syndrome-specific epicentre. To date, no longitudinal neuroimaging study has tested this hypothesis in vivo in frontotemporal dementia spectrum disorders. The aim of this study was to demonstrate that longitudinal progression of atrophy in non-fluent/agrammatic variant primary progressive aphasia spreads over time from a syndrome-specific epicentre to additional regions, based on their connectivity to the epicentre in healthy control subjects...
August 6, 2016: Brain: a Journal of Neurology
Mariana Babo-Rebelo, Craig G Richter, Catherine Tallon-Baudry
UNLABELLED: The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line with theories proposing that selfhood is grounded in the neural monitoring of internal organs, such as the heart. We measured with magnetoencephalograhy neural responses evoked by heartbeats while human participants freely mind-wandered...
July 27, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
R Nathan Spreng, W Dale Stevens, Joseph D Viviano, Daniel L Schacter
Anticorrelation between the default and dorsal attention networks is a central feature of human functional brain organization. Hallmarks of aging include impaired default network modulation and declining medial temporal lobe (MTL) function. However, it remains unclear if this anticorrelation is preserved into older adulthood during task performance, or how this is related to the intrinsic architecture of the brain. We hypothesized that older adults would show reduced within- and increased between-network functional connectivity (FC) across the default and dorsal attention networks...
September 2016: Neurobiology of Aging
Elena Bertossi, Elisa Ciaramelli
Mind-wandering, an ubiquitous expression of humans' mental life, reflects a drift of attention away from the current task towards self-generated thoughts, and has been associated with activity in the brain default network. To date, however, little is understood about the contribution of individual nodes of this network to mind-wandering. Here, we investigated whether the ventromedial prefrontal cortex (vmPFC) is critically involved in mind-wandering, by studying the propensity to mind-wander in patients with lesion to the vmPFC (vmPFC patients), control patients with lesions not involving the vmPFC, and healthy individuals...
November 2016: Social Cognitive and Affective Neuroscience
Elizabeth Andersen
The purpose of clinical practicums is to help nursing students learn from real clinical experiences. In clinical settings, nursing instructors set-aside time at the end of each clinical day for reflective, debriefing discussions that are designed to draw the students' attention to relevant information and help them understand their beliefs and experiences. The students' competence and decision-making skills are enhanced when they are able to reflect on critical incidents or everyday practice events. It is sometimes difficult, however, for instructors to engage students meaningfully in discussions and promote reflection when students are fatigued...
July 2016: Nurse Education in Practice
Joshua L Roffman, Alexandra S Tanner, Hamdi Eryilmaz, Anais Rodriguez-Thompson, Noah J Silverstein, New Fei Ho, Adam Z Nitenson, Daniel B Chonde, Douglas N Greve, Anissa Abi-Dargham, Randy L Buckner, Dara S Manoach, Bruce R Rosen, Jacob M Hooker, Ciprian Catana
Local prefrontal dopamine signaling supports working memory by tuning pyramidal neurons to task-relevant stimuli. Enabled by simultaneous positron emission tomography-magnetic resonance imaging (PET-MRI), we determined whether neuromodulatory effects of dopamine scale to the level of cortical networks and coordinate their interplay during working memory. Among network territories, mean cortical D1 receptor densities differed substantially but were strongly interrelated, suggesting cross-network regulation. Indeed, mean cortical D1 density predicted working memory-emergent decoupling of the frontoparietal and default networks, which respectively manage task-related and internal stimuli...
June 2016: Science Advances
David Maillet, Daniel L Schacter
During cognitive tasks requiring externally directed attention, activation in the default-network (DN) typically decreases below baseline levels ('deactivation'). Healthy aging is associated with reduced deactivation, which is usually attributed to a failure to suppress DN processes. Recent evidence instead suggests that older adults may be more reliant on DN than young adults when performing these tasks.
September 2016: Trends in Cognitive Sciences
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