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Brain Connectivity

Lauren Elizabeth Mak, Luciano Minuzzi, Glenda MacQueen, Geoffrey Hall, Sidney Kennedy, Roumen Milev
OBJECTIVE: When the brain is not engaged in goal-directed activities and at "rest", there are still measureable patterns of activity. One resting state network, the default mode network (DMN) is responsible for a self-referential introspective state. There are many factors that influence normal changes in brain activity. The purpose of this review is to summarize differences in DMN functional connectivity in healthy individuals by age, sex, cognitive function and analysis type to characterize what is "normal"...
December 4, 2016: Brain Connectivity
Anja Baenninger, Vanessa A Palzes, Brian J Roach, Daniel H Mathalon, Judith Ford, Thomas Koenig
Common-phase synchronization of neuronal oscillations is a mechanism by which distributed brain regions can be integrated into transiently stable networks. Based on the hypothesis that schizophrenia is characterized by deficits in functional integration within neuronal networks, this study aimed to explore whether psychotic patients exhibit differences in brain regions involved in integrative mechanisms. We report an EEG-informed fMRI analysis of eyes-open resting state data collected from patients and healthy controls at two study sites...
November 29, 2016: Brain Connectivity
Jingyuan E Chen, Gary Glover, Hesamoddin Jahanian
Recently, emerging studies have demonstrated the existence of brain resting state (RS) spontaneous activity at frequencies higher than the conventional 0.1 Hz. A few groups utilizing accelerated acquisitions have reported persisting signals beyond 1 Hz, which seems too high to be accommodated by the sluggish hemodynamic process underpinning blood-oxygen-level dependent contrasts (the upper limit of the canonical model is ~ 0.3 Hz). It is thus questionable whether the observed high-frequency (HF) functional connectivity (FC) originates from alternative mechanisms (e...
November 22, 2016: Brain Connectivity
Yuncong Ma, Christina Hamilton, Nanyin Zhang
Brain functional connectivity undergoes dynamic changes from the awake to unconscious states. However, how the dynamics of functional connectivity patterns are linked to consciousness at the behavioral level remains elusive. Here we acquired resting-state functional magnetic resonance imaging (rsfMRI) data during wakefulness and graded levels of consciousness in rats. Data were analyzed using a dynamic approach combining the sliding-window method and k-means clustering. Our results demonstrate that whole-brain networks contain several quasi-stable patterns that dynamically recurred from the awake state into anesthetized states...
November 15, 2016: Brain Connectivity
Xinqi Zhou, Taoyu Wu, Jing Yu, Xu Lei
Accumulating evidence supports that sleep deprivation (SD) and aging have similar effects: decreased cognition performance and impaired brain function. Some investigators even proposed the SD as a model of aging. However, few direct comparisons were ever explored between the effects of SD and aging by network module analysis with the resting-state fMRI. In this study, both within- and between-module connectivities were calculated in the whole brain to describe a complete picture of brain networks' functional connectivity among three groups (young normal sleep, young SD and old group)...
October 12, 2016: Brain Connectivity
Sahil Bajaj, Bhim M Adhikari, Karl J Friston, Mukesh Dhamala
Granger causality (GC) and dynamic causal modeling (DCM) are the two key approaches used to determine the directed interactions among brain areas. Recent discussions have provided a constructive account of the merits and demerits. GC, on one side, considers dependencies among measured responses, whereas DCM, on the other, models how neuronal activity in one brain area causes dynamics in another. In this study, our objective was to establish construct validity between GC and DCM in the context of resting state functional magnetic resonance imaging (fMRI)...
September 16, 2016: Brain Connectivity
William Hedley Thompson, Peter Fransson
Assessment of dynamic functional brain connectivity based on functional magnetic resonance imaging (fMRI) data is an increasingly popular strategy to investigate temporal dynamics of the brain's large-scale network architecture. Current practice when deriving connectivity estimates over time is to use the Fisher transformation, which aims to stabilize the variance of correlation values that fluctuate around varying true correlation values. It is, however, unclear how well the stabilization of signal variance performed by the Fisher transformation works for each connectivity time series, when the true correlation is assumed to be fluctuating...
December 2016: Brain Connectivity
Sean R McWhinney, Antoine Tremblay, Thérèse M Chevalier, Vanessa K Lim, Aaron J Newman
Healthy aging has been associated with a global reduction in white matter integrity, which is thought to reflect cognitive decline. The present study aimed to investigate this reduction over a broad range of the life span, using diffusion tensor imaging analyzed with conditional inference random forest modeling (CForest). This approach is sensitive to subtle and potentially nonlinear effects over the age continuum and was used to characterize the progression of decline in greater detail than has been possible in the past...
December 2016: Brain Connectivity
Ariel Haimovici, Pablo Balenzuela, Enzo Tagliazucchi
Synchronization of brain activity fluctuations is believed to represent communication between spatially distant neural processes. These interareal functional interactions develop in the background of a complex network of axonal connections linking cortical and subcortical neurons, termed the human "structural connectome." Theoretical considerations and experimental evidence support the view that the human brain can be modeled as a system operating at a critical point between ordered (subcritical) and disordered (supercritical) phases...
December 2016: Brain Connectivity
Bhim M Adhikari, Martin Norgaard, Kristen M Quinn, Jenine Ampudia, Justin Squirek, Mukesh Dhamala
Musical improvisation offers an excellent experimental paradigm for the study of real-time human creativity. It involves moment-to-moment decision-making, monitoring of one's performance, and utilizing external feedback to spontaneously create new melodies or variations on a melody. Recent neuroimaging studies have begun to study the brain activity during musical improvisation, aiming to unlock the mystery of human creativity. What brain resources come together and how these are utilized during musical improvisation are not well understood...
December 2016: Brain Connectivity
Keith M Vogt, Christopher J Becker, Ajay D Wasan, James W Ibinson
The objective in this study was to directly compare MRI-based functional connectivity between conditions of rest and painful electrical nerve stimulation for key regions involved in pain processing: the anterior and posterior insula and the anterior cingulate cortex. Electric nerve stimulation, rated 7/10 for pain, was delivered to the right index finger of 14 healthy pain-free adult volunteers in four 30-sec blocks and continuously for 2 min. Functional connectivity maps obtained at rest and during both pain tasks were compared using seed time courses from the left anterior and posterior insula and anterior cingulate...
December 2016: Brain Connectivity
Madelon Pijnenburg, S M Hadi Hosseini, Simon Brumagne, Lotte Janssens, Nina Goossens, Karen Caeyenberghs
Individuals with nonspecific low back pain (NSLBP) show an impaired sensorimotor control. They need significantly more time to perform five consecutive sit-to-stand-to-sit (STSTS) movements compared with healthy controls. Optimal sensorimotor control depends on the coactivation of many brain regions, which have to operate as a coordinated network to achieve correct motor output. Therefore, the examination of brain connectivity from a network perspective is crucial for understanding the factors that drive sensorimotor control...
December 2016: Brain Connectivity
Sarah Kann, Sheng Zhang, Peter Manza, Hoi-Chung Leung, Chiang-Shan R Li
Resting-state functional connectivity (rsFC) is widely used to examine cerebral functional organization. The imaging literature has described lateralization of insula activations during cognitive and affective processing. Evidence appears to support a role of the right-hemispheric insula in attentional orientation to salient stimulus, interoception, and physiological arousal, and a role of the left-hemispheric insula in cognitive and affective control, as well as perspective taking. In this study, in a large data set of healthy adults, we examined lateralization of the rsFC of the anterior insula (AI) by computing a laterality index (LI) of connectivity with 54 regions from the Automated Anatomic Labeling atlas...
November 2016: Brain Connectivity
Gregory C Burgess, Sridhar Kandala, Dan Nolan, Timothy O Laumann, Jonathan D Power, Babatunde Adeyemo, Michael P Harms, Steven E Petersen, Deanna M Barch
Like all resting-state functional connectivity data, the data from the Human Connectome Project (HCP) are adversely affected by structured noise artifacts arising from head motion and physiological processes. Functional connectivity estimates (Pearson's correlation coefficients) were inflated for high-motion time points and for high-motion participants. This inflation occurred across the brain, suggesting the presence of globally distributed artifacts. The degree of inflation was further increased for connections between nearby regions compared with distant regions, suggesting the presence of distance-dependent spatially specific artifacts...
November 2016: Brain Connectivity
Lauren E Libero, Wesley K Burge, Hrishikesh D Deshpande, Franco Pestilli, Rajesh K Kana
Autism spectrum disorder (ASD) is a neurodevelopmental disorder found to have widespread alterations in the function and synchrony of brain regions. These differences may underlie alterations in microstructural organization, such as in white matter pathways. To investigate the diffusion of major white matter tracts, the current study examined multiple indices of white matter diffusion in 42 children and adults with ASD and 44 typically developing (TD) age- and IQ-matched peers using diffusion tensor imaging...
November 2016: Brain Connectivity
Chao Zhang, Nathan D Cahill, Mohammad R Arbabshirani, Tonya White, Stefi A Baum, Andrew M Michael
Functional connectivity (FC) in resting-state functional magnetic resonance imaging (rs-fMRI) is widely used to find coactivating regions in the human brain. Despite its widespread use, the effects of sex and age on resting FC are not well characterized, especially during early adulthood. Here we apply regression and graph theoretical analyses to explore the effects of sex and age on FC between the 116 AAL atlas parcellations (a total of 6670 FC measures). rs-fMRI data of 494 healthy subjects (203 males and 291 females; age range: 22-36 years) from the Human Connectome Project were analyzed...
November 2016: Brain Connectivity
Anil K Vasireddi, Alberto L Vazquez, David E Whitney, Mitsuhiro Fukuda, Seong-Gi Kim
Resting-state functional magnetic resonance imaging has been increasingly used for examining connectivity across brain regions. The spatial scale by which hemodynamic imaging can resolve functional connections at rest remains unknown. To examine this issue, deoxyhemoglobin-weighted intrinsic optical imaging data were acquired from the visual cortex of lightly anesthetized ferrets. The neural activity of orientation domains, which span a distance of 0.7-0.8 mm, has been shown to be correlated during evoked activity and at rest...
September 7, 2016: Brain Connectivity
Farras Abdelnour, Ashish Raj, Orrin Devinsky, Thomas Thesen
The two most common types of temporal lobe epilepsy are medial temporal sclerosis (TLE-MTS) epilepsy and MRI-normal temporal lobe epilepsy (TLE-no). TLE-MTS is specified by its stereotyped focus and spread pattern of neuronal damage, with pronounced neuronal loss in the hippocampus. TLE-no exhibits normal-appearing hippocampus and more widespread neuronal loss. In both cases, neuronal loss spread appears to be constrained by the white matter connections. Both varieties of epilepsy reveal pathological abnormalities in increased mean diffusivity (MD)...
September 7, 2016: Brain Connectivity
Luciana Monteiro de Moura, Hugo Cogo-Moreira, Clara Regina Brandão de Ávila, Pedro Mario Pan, Ary Gadelha, Tais Moriyama, Marco Antonio Del Aquilla, Marcelo Hoexter, Giovanni Abrahão Salum, Felipe Almeida Picon, Mauricio Anés, Marcos Tomanik Mercadante, Acioly Lacerda, Edson Amaro, Euripedes Constantino Miguel, Luis Augusto Rohde, Rodrigo Affonseca Bressan, Philip McGuire, João Ricardo Sato, Jair de Jesus Mari, Andrea Parolin Jackowski
Diffusion tensor imaging (DTI) studies showed that microstructural alterations are correlated to reading skills. In this study, we aim to investigate white matter microstructure of a group of Portuguese speakers with poor reading level, using different parameters of DTI. To perform this analysis, we selected children ranging from 8 to 12 years of age, poor readers (n = 17) and good readers (n = 23), evaluated in the word-level ability based on a Latent Class Analysis (LCA) of Academic Performance Test (TDE)...
September 2016: Brain Connectivity
Julia P Owen, Maxwell B Wang, Pratik Mukherjee
The edges of the structural connectome traverse the white matter to connect cortical and subcortical nodes, although the anatomic embedding of these edges is generally overlooked in the literature. Characterization of the geometry of the structural connectome could provide an improved understanding of the relative importance of various white matter regions to the network architecture of the human brain in normal development and aging, as well as in white matter diseases with regionally specific patterns of vulnerability...
September 2016: Brain Connectivity
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