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https://www.readbyqxmd.com/read/28077184/abnormalities-in-the-effective-connectivity-of-visuothalamic-circuitry-in-schizophrenia
#1
S J Iwabuchi, L Palaniyappan
BACKGROUND: Sensory-processing deficits appear crucial to the clinical expression of symptoms of schizophrenia. The visual cortex displays both dysconnectivity and aberrant spontaneous activity in patients with persistent symptoms and cognitive deficits. In this paper, we examine visual cortex in the context of the remerging notion of thalamic dysfunction in schizophrenia. We examined specific regional and longer-range abnormalities in sensory and thalamic circuits in schizophrenia, and whether these patterns are strong enough to discriminate symptomatic patients from controls...
January 12, 2017: Psychological Medicine
https://www.readbyqxmd.com/read/28073788/dopamine-controls-parkinson-s-tremor-by-inhibiting-the-cerebellar-thalamus
#2
Michiel F Dirkx, Hanneke E M den Ouden, Esther Aarts, Monique H M Timmer, Bastiaan R Bloem, Ivan Toni, Rick C Helmich
Parkinson's resting tremor is related to altered cerebral activity in the basal ganglia and the cerebello-thalamo-cortical circuit. Although Parkinson's disease is characterized by dopamine depletion in the basal ganglia, the dopaminergic basis of resting tremor remains unclear: dopaminergic medication reduces tremor in some patients, but many patients have a dopamine-resistant tremor. Using pharmacological functional magnetic resonance imaging, we test how a dopaminergic intervention influences the cerebral circuit involved in Parkinson's tremor...
January 9, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28065836/learning-effective-connectivity-from-fmri-using-autoregressive-hidden-markov-model-with-missing-data
#3
Shilpa Dang, Santanu Chaudhury, Brejesh Lall, Prasun Kumar Roy
BACKGROUND: Effective connectivity (EC) analysis of neuronal groups using fMRI delivers insights about functional-integration. However, fMRI signal has low-temporal resolution due to down-sampling and indirectly measures underlying neuronal activity. NEW METHOD: The aim is to address above issues for more reliable EC estimates. This paper proposes use of autoregressive hidden Markov model with missing data (AR-HMM-md) in dynamically multi-linked (DML) framework for learning EC using multiple fMRI time series...
January 5, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28057725/the-neuro-computational-architecture-of-value-based-selection-in-the-human-brain
#4
Philippe Domenech, Jérôme Redouté, Etienne Koechlin, Jean-Claude Dreher
Current neural models of value-based decision-making consider choices as a 2-stage process, proceeding from the "valuation" of each option under consideration to the "selection" of the best option on the basis of their subjective values. However, little is known about the computational mechanisms at play at the selection stage and its implementation in the human brain. Here, we used drift-diffusion models combined with model-based functional magnetic resonance imaging, effective connectivity, and multivariate pattern analysis to characterize the neuro-computational architecture of value-based decisions...
January 4, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28035239/identifying-patterns-of-dispersal-connectivity-and-selection-in-the-sea-scallop-placopecten-magellanicus-using-radseq-derived-snps
#5
Mallory Van Wyngaarden, Paul V R Snelgrove, Claudio DiBacco, Lorraine C Hamilton, Naiara Rodríguez-Ezpeleta, Nicholas W Jeffery, Ryan R E Stanley, Ian R Bradbury
Understanding patterns of dispersal and connectivity among marine populations can directly inform fisheries conservation and management. Advances in high-throughput sequencing offer new opportunities for estimating marine connectivity. We used restriction-site-associated DNA sequencing to examine dispersal and realized connectivity in the sea scallop Placopecten magellanicus, an economically important marine bivalve. Based on 245 individuals sampled rangewide at 12 locations from Newfoundland to the Mid-Atlantic Bight, we identified and genotyped 7163 single nucleotide polymorphisms; 112 (1...
January 2017: Evolutionary Applications
https://www.readbyqxmd.com/read/28031223/disrupted-prediction-errors-index-social-deficits-in-autism-spectrum-disorder
#6
Joshua H Balsters, Matthew A J Apps, Dimitris Bolis, Rea Lehner, Louise Gallagher, Nicole Wenderoth
Social deficits are a core symptom of autism spectrum disorder; however, the perturbed neural mechanisms underpinning these deficits remain unclear. It has been suggested that social prediction errors-coding discrepancies between the predicted and actual outcome of another's decisions-might play a crucial role in processing social information. While the gyral surface of the anterior cingulate cortex signalled social prediction errors in typically developing individuals, this crucial social signal was altered in individuals with autism spectrum disorder...
January 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28018680/distinctive-structural-and-effective-connectivity-changes-of-semantic-cognition-network-across-left-and-right-mesial-temporal-lobe-epilepsy-patients
#7
Xiaotong Fan, Hao Yan, Yi Shan, Kun Shang, Xiaocui Wang, Peipei Wang, Yongzhi Shan, Jie Lu, Guoguang Zhao
Occurrence of language impairment in mesial temporal lobe epilepsy (mTLE) patients is common and left mTLE patients always exhibit a primary problem with access to names. To explore different neuropsychological profiles between left and right mTLE patients, the study investigated both structural and effective functional connectivity changes within the semantic cognition network between these two groups and those from normal controls. We found that gray matter atrophy of left mTLE patients was more severe than that of right mTLE patients in the whole brain and especially within the semantic cognition network in their contralateral hemisphere...
2016: Neural Plasticity
https://www.readbyqxmd.com/read/28012852/mapping-effective-connectivity-in-the-human-brain-with-concurrent-intracranial-electrical-stimulation-and-bold-fmri
#8
Hiroyuki Oya, Matthew A Howard, Vincent A Magnotta, Anton Kruger, Timothy D Griffiths, Louis Lemieux, David W Carmichael, Christopher I Petkov, Hiroto Kawasaki, Christopher K Kovach, Matthew J Sutterer, Ralph Adolphs
BACKGROUND: Understanding brain function requires knowledge of how one brain region causally influences another. This information is difficult to obtain directly in the human brain, and is instead typically inferred from resting-state fMRI. NEW METHOD: Here, we demonstrate the safety and scientific promise of a novel and complementary approach: concurrent electrical stimulation and fMRI (es-fMRI) at 3T in awake neurosurgical patients with implanted depth electrodes...
December 21, 2016: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28009080/disruptions-in-the-left-frontoparietal-network-underlie-resting-state-endophenotypic-markers-in-schizophrenia
#9
George Chahine, Anja Richter, Sarah Wolter, Roberto Goya-Maldonado, Oliver Gruber
Advances in functional brain imaging have improved the search for potential endophenotypic markers in schizophrenia. Here, we employed independent component analysis (ICA) and dynamic causal modeling (DCM) in resting state fMRI on a sample of 35 schizophrenia patients, 20 first-degree relatives and 35 control subjects. Analysis on ICA-derived networks revealed increased functional connectivity between the left frontoparietal network (FPN) and left temporal and parietal regions in schizophrenia patients (P < 0...
December 23, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/28004954/successful-and-unsuccessful-response-inhibitions-differentially-affect-the-effective-connectivity-between-insular-presupplementary-motor-and-striatal-areas
#10
Roberto Limongi, Francisco J Pérez
Successful response inhibition depends upon the delay between the cues that signal a response and its subsequent inhibition. Previous studies report activity in the right presupplementary motor area (rPreSMA), right anterior insula (rAI), and the right striatum (rSTR) when subjects attempt to inhibit responses. Although these regions are anatomically connected, how they interact during successful and unsuccessful inhibitions has not been studied. In this work, we used a temporal prediction task, functional MRI, and dynamic causal modeling to solve this question...
December 22, 2016: Behavioral Neuroscience
https://www.readbyqxmd.com/read/28004273/occipital-nerve-field-transcranial-direct-current-stimulation-normalizes-imbalance-between-pain-detecting-and-pain-inhibitory-pathways-in-fibromyalgia
#11
Dirk De Ridder, Sven Vanneste
Occipital nerve field (OCF) stimulation with subcutaneously implanted electrodes is used to treat headaches, more generalized pain, and even failed back surgery syndrome via unknown mechanisms. Transcranial direct current stimulation (tDCS) can predict the efficacy of implanted electrodes. The purpose of this study is to unravel the neural mechanisms involved in global pain suppression, mediated by occipital nerve field stimulation, within the realm of fibromyalgia. Nineteen patients with fibromyalgia underwent a placebo-controlled OCF tDCS...
December 21, 2016: Neurotherapeutics: the Journal of the American Society for Experimental NeuroTherapeutics
https://www.readbyqxmd.com/read/28003158/central-sensitization-related-changes-of-effective-and-functional-connectivity-in-the-rat-inflammatory-trigeminal-pain-model
#12
Tamás Spisák, Zsófia Pozsgay, Csaba Aranyi, Szabolcs Dávid, Pál Kocsis, Gabriella Nyitrai, Dávid Gajári, Miklós Emri, András Czurkó, Zsigmond Tamás Kincses
Central sensitization is a key mechanism in the pathology of several neuropathic pain disorders. We aimed to investigate the underlying brain connectivity changes in a rat model of chronic pain. Non-noxious whisker stimulation was used to evoke blood-oxygen-level-dependent (BOLD) responses in a block-design functional Magnetic Resonance Imaging (fMRI) experiment on 9.4T. Measurements were repeated two days and one week after injecting complete Freund's adjuvant into the rats' whisker pad. We found that acute pain reduced activation in the barrel cortex, most probably due to a plateau effect...
December 18, 2016: Neuroscience
https://www.readbyqxmd.com/read/28001074/mesoscopic-correlation-functions-in-heterogeneous-ionic-liquids
#13
Henning Weiss, Julian Mars, Hailong Li, Gunnar Kircher, Oxana Ivanova, Artem Feoktystov, Olaf Soltwedel, Markus Bier, Markus Mezger
A common feature of ionic liquids composed of cations with long aliphatic side chains is structural heterogeneities on the nanometer length scale. This so-called microphase separation arises from the clustering of aliphatic moieties. The temperature dependence of the liquid bulk structure was studied by small-angle X-ray and neutron scattering for a set of methylimidazolium ([C18C1im](+), [C22C1im](+)) based ionic liquids with tris(pentafluoroethyl)trifluorophosphate ([FAP](-)), bis(trifluoromethylsulfonyl)imide ([NTf2](-)), and bis(nonafluorobutylsulfonyl)imide ([NNf2](-)) anions...
January 12, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/27998996/effective-amygdala-prefrontal-connectivity-predicts-individual-differences-in-successful-emotion-regulation
#14
Carmen Morawetz, Stefan Bode, Juergen Baudewig, Hauke R Heekeren
The ability to voluntarily regulate our emotional response to threatening and highly arousing stimuli by using cognitive reappraisal strategies is essential for our mental and physical well-being. This might be achieved by prefrontal brain regions (e.g., inferior frontal gyrus, IFG) down-regulating activity in the amygdala. It is unknown, to which degree effective connectivity within the emotion-regulation network is linked to individual differences in reappraisal skills. Using psychophysiological interaction (PPI) analyses of functional magnetic resonance imaging data, we examined changes in inter-regional connectivity between the amygdala and IFG with other brain regions during reappraisal of emotional responses and used emotion regulation success as an explicit regressor...
December 20, 2016: Social Cognitive and Affective Neuroscience
https://www.readbyqxmd.com/read/27951437/engagement-of-the-left-extrastriate-body-area-during-body-part-metaphor-comprehension
#15
Simon Lacey, Randall Stilla, Gopikrishna Deshpande, Sinan Zhao, Careese Stephens, Kelly McCormick, David Kemmerer, K Sathian
Grounded cognition explanations of metaphor comprehension predict activation of sensorimotor cortices relevant to the metaphor's source domain. We tested this prediction for body-part metaphors using functional magnetic resonance imaging while participants heard sentences containing metaphorical or literal references to body parts, and comparable control sentences. Localizer scans identified body-part-specific motor, somatosensory and visual cortical regions. Both subject- and item-wise analyses showed that, relative to control sentences, metaphorical but not literal sentences evoked limb metaphor-specific activity in the left extrastriate body area (EBA), paralleling the EBA's known visual limb-selectivity...
December 9, 2016: Brain and Language
https://www.readbyqxmd.com/read/27913429/heritability-of-the-effective-connectivity-in-the-resting-state-default-mode-network
#16
Junhai Xu, Xuntao Yin, Haitao Ge, Yan Han, Zengchang Pang, Baolin Liu, Shuwei Liu, Karl Friston
The default mode network (DMN) is thought to reflect endogenous neural activity, which is considered as one of the most intriguing phenomena in cognitive neuroscience. Previous studies have found that key regions within the DMN are highly interconnected. Here, we characterized the genetic influences on causal or directed information flow within the DMN during the resting state. In this study, we recruited 46 pairs of twins and collected fMRI imaging data using a 3.0 T scanner. Dynamic causal modeling was conducted for each participant, and a structural equation model was used to calculate the heritability of DMN in terms of its effective connectivity...
November 23, 2016: Cerebral Cortex
https://www.readbyqxmd.com/read/27895566/allostatic-self-efficacy-a-metacognitive-theory-of-dyshomeostasis-induced-fatigue-and-depression
#17
Klaas E Stephan, Zina M Manjaly, Christoph D Mathys, Lilian A E Weber, Saee Paliwal, Tim Gard, Marc Tittgemeyer, Stephen M Fleming, Helene Haker, Anil K Seth, Frederike H Petzschner
This paper outlines a hierarchical Bayesian framework for interoception, homeostatic/allostatic control, and meta-cognition that connects fatigue and depression to the experience of chronic dyshomeostasis. Specifically, viewing interoception as the inversion of a generative model of viscerosensory inputs allows for a formal definition of dyshomeostasis (as chronically enhanced surprise about bodily signals, or, equivalently, low evidence for the brain's model of bodily states) and allostasis (as a change in prior beliefs or predictions which define setpoints for homeostatic reflex arcs)...
2016: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/27881959/effective-connectivity-within-the-mesocorticolimbic-system-during-resting-state-in-cocaine-users
#18
Suchismita Ray, Xin Di, Bharat B Biswal
Objective: Although effective connectivity between brain regions has been examined in cocaine users during tasks, no effective connectivity study has been conducted on cocaine users during resting-state. In the present functional magnetic resonance imaging study, we examined effective connectivity in resting-brain, between the brain regions within the mesocorticolimbic dopamine system, implicated in reward and motivated behavior, while the chronic cocaine users and controls took part in a resting-state scan by using a spectral Dynamic causal modeling (spDCM) approach...
2016: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/27870851/a-normalization-framework-for-emotional-attention
#19
Xilin Zhang, Shruti Japee, Zaid Safiullah, Nicole Mlynaryk, Leslie G Ungerleider
The normalization model of attention proposes that attention can affect performance by response- or contrast-gain changes, depending on the size of the stimulus and attention field. Here, we manipulated the attention field by emotional valence, negative faces versus positive faces, while holding stimulus size constant in a spatial cueing task. We observed changes in the cueing effect consonant with changes in response gain for negative faces and contrast gain for positive faces. Neuroimaging experiments confirmed that subjects' attention fields were narrowed for negative faces and broadened for positive faces...
November 2016: PLoS Biology
https://www.readbyqxmd.com/read/27868393/atypical-effective-connectivity-of-thalamo-cortical-circuits-in-autism-spectrum-disorder
#20
Heng Chen, Lucina Q Uddin, Youxue Zhang, Xujun Duan, Huafu Chen
Autism spectrum disorder (ASD) is a neurodevelopment disorder characterized by atypical connectivity within and across multiple brain systems. We aimed to explore information transmission from the sensory periphery to information processing centers of the brain across thalamo-cortical circuits in ASD. A large multicenter dataset from the autism brain imaging data exchange was utilized. A thalamus template derived from the Automatic Anatomic Labeling atlas was subdivided into six subregions corresponding to six cortical regions using a "winner-takes-all" strategy...
November 2016: Autism Research: Official Journal of the International Society for Autism Research
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