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"effective connectivity"

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https://www.readbyqxmd.com/read/28733247/effective-connectivity-during-successful-and-unsuccessful-recollection-in-young-and-old-adults
#1
Selene Cansino, Patricia Trejo-Morales, Cinthya Estrada-Manilla, Erick Humberto Pasaye-Alcaraz, Erika Aguilar-Castañeda, Perla Salgado-Lujambio, Ana Luisa Sosa-Ortiz
Aging effects on regional brain activation have been studied extensively to explain the gradual recollection failure that occurs with advancing age. However, little is known about the consequence of aging on the interaction among brain regions that support recollection. The purpose of this study was to examine effective connectivity at encoding and retrieval during successful and unsuccessful recollection in young and old adults. In particular, we analyzed a recollection network that is characterized by its susceptibility to aging effects by middle age or later, which is comprised of the occipital cortex, hippocampus and orbitofrontal cortex...
July 18, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28729938/abnormal-resting-state-effective-connectivity-within-the-default-mode-network-in-major-depressive-disorder-a-spectral-dynamic-causal-modeling-study
#2
Liang Li, Baojuan Li, Yuanhan Bai, Wenlei Liu, Huaning Wang, Hoi-Chung Leung, Ping Tian, Linchuan Zhang, Fan Guo, Long-Biao Cui, Hong Yin, Hongbing Lu, Qingrong Tan
INTRODUCTION: Understanding the neural basis underlying major depressive disorder (MDD) is essential for the diagnosis and treatment of this mental disorder. Aberrant activation and functional connectivity of the default mode network (DMN) have been consistently found in patients with MDD. It is not known whether effective connectivity within the DMN is altered in MDD. OBJECTS: The primary object of this study is to investigate the effective connectivity within the DMN during resting state in MDD patients before and after eight weeks of antidepressant treatment...
July 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28720781/distinct-top-down-and-bottom-up-brain-connectivity-during-visual-perception-and-imagery
#3
N Dijkstra, P Zeidman, S Ondobaka, M A J van Gerven, K Friston
Research suggests that perception and imagination engage neuronal representations in the same visual areas. However, the underlying mechanisms that differentiate sensory perception from imagination remain unclear. Here, we examine the directed coupling (effective connectivity) between fronto-parietal and visual areas during perception and imagery. We found an increase in bottom-up coupling during perception relative to baseline and an increase in top-down coupling during both perception and imagery, with a much stronger increase during imagery...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28717158/neural-processing-of-biological-motion-in-autism-an-investigation-of-brain-activity-and-effective-connectivity
#4
Kaat Alaerts, Stephan P Swinnen, Nicole Wenderoth
The superior temporal sulcus (STS) forms a key region for social information processing and disruptions of its function have been associated with socio-communicative impairments characteristic of autism spectrum disorders (ASD). Task-based fMRI was applied in 15 adults with ASD and 15 matched typical-controls (TC) to explore differences in activity and effective connectivity of STS while discriminating either 'intact' versus 'scrambled' biological motion point light displays (explicit processing) or responding to a color-change while the 'intact' versus 'scrambled' nature of the stimulus was irrelevant for the task (implicit processing)...
July 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28713237/behavioral-and-neural-correlates-of-executive-function-interplay-between-inhibition-and-updating-processes
#5
Na Young Kim, Ellen Wittenberg, Chang S Nam
This study investigated the interaction between two executive function processes, inhibition and updating, through analyses of behavioral, neurophysiological, and effective connectivity metrics. Although, many studies have focused on behavioral effects of executive function processes individually, few studies have examined the dynamic causal interactions between these two functions. A total of twenty participants from a local university performed a dual task combing flanker and n-back experimental paradigms, and completed the Operation Span Task designed to measure working memory capacity...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28709921/effects-of-pattern-masks-on-the-formation-of-perceptual-grouping
#6
Daniel D Kurylo, Farhan Bukhari
Mechanisms underlying perceptual grouping serve to bind stimulus components that are contained within grouped patterns. In order to examine the time course of grouping development, grids of spatially isolated dots were followed by pattern masks across a range of SOA. Subjects indicated the predominant perceived grouping of the dot patterns. Masks either spatially superimposed target elements (element mask), or superimposed elements as well as paths among elements (connection mask). Element masks thereby disrupted processing of target elements, while connection masks additionally disrupted representations in regions among elements...
July 11, 2017: Vision Research
https://www.readbyqxmd.com/read/28702345/hierarchical-disruption-in-the-bayesian-brain-focal-epilepsy-and-brain-networks
#7
Amir Omidvarnia, Mangor Pedersen, Richard E Rosch, Karl J Friston, Graeme D Jackson
In this opinion paper, we describe a combined view of functional and effective brain connectivity along with the free-energy principle for investigating persistent disruptions in brain networks of patients with focal epilepsy. These changes are likely reflected in effective connectivity along the cortical hierarchy and construct the basis of increased local functional connectivity in focal epilepsy. We propose a testable framework based on dynamic causal modelling and functional connectivity analysis with the capacity of explaining commonly observed connectivity changes during interictal periods...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28701822/the-difference-of-neural-networks-between-bimanual-antiphase-and-in-phase-upper-limb-movements-a-preliminary-functional-magnetic-resonance-imaging-study
#8
Qiang Lin, Hai Li, Yu-Rong Mao, Wai-Leung Lo, Jiang-Li Zhao, Ling Chen, Yan Leng, Dong-Feng Huang, Le Li
Most daily movements require some degree of collaboration between the upper limbs. The neural mechanisms are bimanual-condition specific and therefore should be different between different activities. In this study, we aimed to explore intraregional activation and interregional connectivity during bimanual movement by functional magnetic resonance imaging (fMRI). Ten right-handed, normal subjects were recruited. The neural correlates of unimanual (right side) and bimanual (in-phase and antiphase) upper limb movements were investigated...
2017: Behavioural Neurology
https://www.readbyqxmd.com/read/28690506/effective-connectivity-between-ventral-occipito-temporal-and-ventral-inferior-frontal-cortex-during-lexico-semantic-processing-a-dynamic-causal-modeling-study
#9
Marcela Perrone-Bertolotti, Louise Kauffmann, Cédric Pichat, Juan R Vidal, Monica Baciu
It has been suggested that dorsal and ventral pathways support distinct aspects of language processing. Yet, the full extent of their involvement and their inter-regional connectivity in visual word recognition is still unknown. Studies suggest that they might reflect the dual-route model of reading, with the dorsal pathway more involved in grapho-phonological conversion during phonological tasks, and the ventral pathway performing lexico-semantic access during semantic tasks. Furthermore, this subdivision is also suggested at the level of the inferior frontal cortex, involving ventral and dorsal parts for lexico-semantic and phonological processing, respectively...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28682595/scalable-fabrication-and-integration-of-graphene-microsupercapacitors-through-full-inkjet-printing
#10
Jiantong Li, Szymon Sollami Delekta, Panpan Zhang, Sheng Yang, Martin R Lohe, Xiaodong Zhuang, Xinliang Feng, Mikael Östling
A simple full-inkjet-printing technique is developed for the scalable fabrication of graphene-based microsupercapacitors (MSCs) on various substrates. High-performance graphene inks are formulated by integrating the electrochemically exfoliated graphene with a solvent exchange technique to reliably print graphene interdigitated electrodes with tunable geometry and thickness. Along with the printed polyelectrolyte, poly(4-styrenesulfonic acid), the fully printed graphene-based MSCs attain the highest areal capacitance of ∼0...
July 17, 2017: ACS Nano
https://www.readbyqxmd.com/read/28680119/increased-stability-and-breakdown-of-brain-effective-connectivity-during-slow-wave-sleep-mechanistic-insights-from-whole-brain-computational-modelling
#11
Beatrice M Jobst, Rikkert Hindriks, Helmut Laufs, Enzo Tagliazucchi, Gerald Hahn, Adrián Ponce-Alvarez, Angus B A Stevner, Morten L Kringelbach, Gustavo Deco
Recent research has found that the human sleep cycle is characterised by changes in spatiotemporal patterns of brain activity. Yet, we are still missing a mechanistic explanation of the local neuronal dynamics underlying these changes. We used whole-brain computational modelling to study the differences in global brain functional connectivity and synchrony of fMRI activity in healthy humans during wakefulness and slow-wave sleep. We applied a whole-brain model based on the normal form of a supercritical Hopf bifurcation and studied the dynamical changes when adapting the bifurcation parameter for all brain nodes to best match wakefulness and slow-wave sleep...
July 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28674507/impaired-coupling-between-the-dorsomedial-prefrontal-cortex-and-the-amygdala-in-schizophrenia-smokers-viewing-anti-smoking-images
#12
Stéphane Potvin, Andràs Tikàsz, Ovidiu Lungu, Emmanuel Stip, Vesséla Zaharieva, Pierre Lalonde, Olivier Lipp, Adrianna Mendrek
BACKGROUND: Cigarette smoking is highly prevalent in schizophrenia and is one of the main factors contributing to the significantly decreased life expectancy in this population. Schizophrenia smokers, compared to their counterparts with no comorbid psychiatric disorder, are largely unaware and indifferent to the long-term negative consequences of cigarette smoking. The objective of this study was to determine, for the first time, if these meta-cognitive deficits are associated with neuro-functional alterations in schizophrenia smokers...
2017: Frontiers in Psychiatry
https://www.readbyqxmd.com/read/28666344/hippocampal-engagement-during-recall-depends-on-memory-content
#13
David A Ross, Patrick Sadil, D Merika Wilson, Rosemary A Cowell
The hippocampus is considered pivotal to recall, allowing retrieval of information not available in the immediate environment. In contrast, neocortex is thought to signal familiarity, contributing to recall only when called upon by the hippocampus. However, this view is not compatible with representational accounts of memory, which reject the mapping of cognitive processes onto brain regions. According to representational accounts, the hippocampus is not engaged by recall per se, rather it is engaged whenever hippocampal representations are required...
June 28, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28657186/novel-psychoactive-substances-nps-use-in-severe-mental-illness-smi-patients-potential-changes-in-the-phenomenology-of-psychiatric-diseases
#14
Giuseppe Bersani, Elisabeth Prevete
OBJECTIVE: Literature is quite poor about the clinical effects of novel psychoactive substances (NPS) and the long-term consequences of NPS use in psychiatric patients. Consequently, it is of the greatest interest to examine which effects NPS can exert in patients with previous severe mental illness (SMI), such as psychotic patients. The aim of this work was a comprehensive review about NPS use in patients with SMI. METHODS: We searched Medline or PubMed for relevant English-language citations and reviews describing relationships between NPS use and mental disorders, as well as for the main groups of substances and associated psychiatric manifestations...
May 2017: Human Psychopharmacology
https://www.readbyqxmd.com/read/28652969/interindividual-differences-in-motor-network-connectivity-and-behavioral-response-to-itbs-in-stroke-patients
#15
Svenja Diekhoff-Krebs, Eva-Maria Pool, Anna-Sophia Sarfeld, Anne K Rehme, Simon B Eickhoff, Gereon R Fink, Christian Grefkes
Cerebral plasticity-inducing approaches like repetitive transcranial magnetic stimulation (rTMS) are of high interest in situations where reorganization of neural networks can be observed, e.g., after stroke. However, an increasing number of studies suggest that improvements in motor performance of the stroke-affected hand following modulation of primary motor cortex (M1) excitability by rTMS shows a high interindividual variability. We here tested the hypothesis that in stroke patients the interindividual variability of behavioral response to excitatory rTMS is related to interindividual differences in network connectivity of the stimulated region...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28652333/functional-selectivity-for-face-processing-in-the-temporal-voice-area-of-early-deaf-individuals
#16
Stefania Benetti, Markus J van Ackeren, Giuseppe Rabini, Joshua Zonca, Valentina Foa, Francesca Baruffaldi, Mohamed Rezk, Francesco Pavani, Bruno Rossion, Olivier Collignon
Brain systems supporting face and voice processing both contribute to the extraction of important information for social interaction (e.g., person identity). How does the brain reorganize when one of these channels is absent? Here, we explore this question by combining behavioral and multimodal neuroimaging measures (magneto-encephalography and functional imaging) in a group of early deaf humans. We show enhanced selective neural response for faces and for individual face coding in a specific region of the auditory cortex that is typically specialized for voice perception in hearing individuals...
June 26, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28645842/opennft-an-open-source-python-matlab-framework-for-real-time-fmri-neurofeedback-training-based-on-activity-connectivity-and-multivariate-pattern-analysis
#17
Yury Koush, John Ashburner, Evgeny Prilepin, Ronald Sladky, Peter Zeidman, Sergei Bibikov, Frank Scharnowski, Artem Nikonorov, Dimitri Van De Ville
Neurofeedback based on real-time functional magnetic resonance imaging (rt-fMRI) is a novel and rapidly developing research field. It allows for training of voluntary control over localized brain activity and connectivity and has demonstrated promising clinical applications. Because of the rapid technical developments of MRI techniques and the availability of high-performance computing, new methodological advances in rt-fMRI neurofeedback become possible. Here we outline the core components of a novel open-source neurofeedback framework, termed Open NeuroFeedback Training (OpenNFT), which efficiently integrates these new developments...
June 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28645841/how-do-self-interest-and-other-need-interact-in-the-brain-to-determine-altruistic-behavior
#18
Jie Hu, Yue Li, Yunlu Yin, Philip R Blue, Hongbo Yu, Xiaolin Zhou
Altruistic behavior, i.e., promoting the welfare of others at a cost to oneself, is subserved by the integration of various social, affective, and economic factors represented in extensive brain regions. However, it is unclear how different regions interact to process/integrate information regarding the helper's interest and recipient's need when deciding whether to behave altruistically. Here we combined an interactive game with functional Magnetic Resonance Imaging (fMRI) and transcranial direct current stimulation (tDCS) to characterize the neural network underlying the processing/integration of self-interest and other-need...
June 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28614395/eeg-based-motor-network-biomarkers-for-identifying-target-patients-with-stroke-for-upper-limb-rehabilitation-and-its-construct-validity
#19
Chun-Chuan Chen, Si-Huei Lee, Wei-Jen Wang, Yu-Chen Lin, Mu-Chun Su
Rehabilitation is the main therapeutic approach for reducing poststroke functional deficits in the affected upper limb; however, significant between-patient variability in rehabilitation efficacy indicates the need to target patients who are likely to have clinically significant improvement after treatment. Many studies have determined robust predictors of recovery and treatment gains and yielded many great results using linear approachs. Evidence has emerged that the nonlinearity is a crucial aspect to study the inter-areal communication in human brains and abnormality of oscillatory activities in the motor system is linked to the pathological states...
2017: PloS One
https://www.readbyqxmd.com/read/28606210/impulsivity-as-a-mechanism-linking-child-abuse-and-neglect-with-substance-use-in-adolescence-and-adulthood
#20
Assaf Oshri, Steve M Kogan, Josephine A Kwon, K A S Wickrama, Lauren Vanderbroek, Abraham A Palmer, James MacKillop
Emerging developmental perspectives suggest that adverse rearing environments promote neurocognitive adaptations that heighten impulsivity and increase vulnerability to risky behavior. Although studies document links between harsh rearing environments and impulsive behavior on substance use, the developmental hypothesis that impulsivity acts as mechanism linking adverse rearing environments to downstream substance use remains to be investigated. The present study investigated the role of impulsivity in linking child abuse and neglect with adult substance use using data from (a) a longitudinal sample of youth (Study 1, N = 9,421) and (b) a cross-sectional sample of adults (Study 2, N = 1,011)...
June 13, 2017: Development and Psychopathology
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