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tensor network

Peter W Fettes, Massieh Moayedi, Katharine Dunlop, Farrokh Mansouri, Fidel Vila-Rodriguez, Peter Giacobbe, Karen D Davis, Raymond W Lam, Sidney H Kennedy, Zafiris J Daskalakis, Daniel M Blumberger, Jonathan Downar
BACKGROUND: Approximately 30% of patients with major depressive disorder develop treatment-nonresponsive depression (TNRD); novel interventions targeting the substrates of this illness population are desperately needed. Convergent evidence from lesion, stimulation, connectivity, and functional neuroimaging studies implicates the frontopolar cortex (FPC) as a particularly important region in TNRD pathophysiology; regions functionally connected to the FPC, once identified, could present favorable targets for novel brain stimulation treatments...
April 2018: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
Eleonora Tavazzi, Niels Bergsland, Davide Cattaneo, Elisa Gervasoni, Maria Marcella Laganà, Ottavia Dipasquale, Cristina Grosso, Francesca Lea Saibene, Francesca Baglio, Marco Rovaris
BACKGROUND: Rehabilitation seems to promote brain plasticity, but objective measures of efficacy are lacking and there is a limited understanding of the mechanisms underlying functional recovery. OBJECTIVE: To study functional and structural brain changes induced by gait rehabilitation. METHODS: We enrolled MS inpatients (EDSS 4.5-6.5) undergoing a 4-week neurorehabilitation. Several clinical measures were obtained, including: 2-min walk test (2MWT), dynamic gait index (DGI), Berg balance scale (BBS)...
April 7, 2018: Journal of Neurology
Melisa Carrasco, Jamie Perin, Jacky M Jennings, Charlamaine Parkinson, Maureen M Gilmore, Raul Chavez-Valdez, An N Massaro, Raymond C Koehler, Frances J Northington, Aylin Tekes, Jennifer K Lee
BACKGROUND: Deviation of mean arterial blood pressure (MAP) from the range that optimizes cerebral autoregulatory vasoreactivity (optimal MAP) could increase neurological injury from hypoxic-ischemic encephalopathy (HIE). We tested whether a global magnetic resonance imaging (MRI) brain injury score and regional diffusion tensor imaging (DTI) are associated with optimal MAP in neonates with HIE. METHODS: Twenty-five neonates cooled for HIE were monitored with the hemoglobin volume index...
April 2, 2018: Pediatric Neurology
Yujun Gao, Jinou Zheng, Yaping Li, Danni Guo, Mingli Wang, Xiangxiang Cui, Wei Ye
Patients with temporal lobe epilepsy (TLE) often suffer from alertness alterations. However, specific regions connected with alertness remain controversial, and whether these regions have structural impairment is also elusive. This study aimed to investigate the characteristics and neural mechanisms underlying the functions and structures of alertness network in patients with right-sided temporal lobe epilepsy (rTLE) by performing the attentional network test (ANT), resting-state functional magnetic resonance imaging (R-SfMRI), and diffusion tensor imaging (DTI)...
April 2018: Medicine (Baltimore)
Julie M Hall, James M Shine, Kaylena A Ehgoetz Martens, Moran Gilat, Kathryn M Broadhouse, Jennifer Y Y Szeto, Courtney C Walton, Ahmed A Moustafa, Simon J G Lewis
Freezing of gait (FOG) is a common symptom in advanced Parkinson's disease (PD). Despite current advances, the neural mechanisms underpinning this disturbance remain poorly understood. To this end, we investigated the structural organisation of the white matter connectome in PD freezers and PD non-freezers. We hypothesized that freezers would show an altered network architecture, which could hinder the effective information processing that characterizes the disorder. Twenty-six freezers and twenty-four well-matched non-freezers were included in this study...
April 3, 2018: Journal of Neurology
Domenico Felice, Carlo Cafaro, Stefano Mancini
Research on the use of information geometry (IG) in modern physics has witnessed significant advances recently. In this review article, we report on the utilization of IG methods to define measures of complexity in both classical and, whenever available, quantum physical settings. A paradigmatic example of a dramatic change in complexity is given by phase transitions (PTs). Hence, we review both global and local aspects of PTs described in terms of the scalar curvature of the parameter manifold and the components of the metric tensor, respectively...
March 2018: Chaos
Zhuang Song, Michelle E Farrell, Xi Chen, Denise C Park
The fornix and parahippocampal cingulum are 2 major limbic tracts in the core memory network of the hippocampus. Although these fiber tracts are known to degrade with Alzheimer's disease (AD), little is known about their vulnerability in the asymptomatic phase of AD. In this longitudinal study of cognitively normal adults, we assessed amyloid-beta (Aβ) plaques using positron emission tomography and white matter microstructure using diffusion tensor imaging. We found that an increase of neocortical Aβ burden over time was associated with an increase of radial diffusivity in the fornix but not in the parahippocampal cingulum...
March 6, 2018: Neurobiology of Aging
Eva Rikandi, Teemu Mäntylä, Maija Lindgren, Tuula Kieseppä, Jaana Suvisaari, Tuukka T Raij
BACKGROUND: Functional connectivity is altered in psychotic disorders. Multiple findings concentrate on the default mode network, anchored on the precuneus-posterior cingulate cortex (PC-PCC). However, the nature of the alterations varies between studies and connectivity alterations have not been studied during an ecologically valid natural stimulus. In the present study, we investigated the functional and structural connectivity of a PC-PCC region, where functioning differentiated first-episode psychosis patients from control subjects during free viewing of a movie in our earlier study...
March 24, 2018: Schizophrenia Research
Shi-Jun Li, Yi Wang, Long Qian, Gang Liu, Shuang-Feng Liu, Li-Ping Zou, Ji-Shui Zhang, Nan Hu, Xiao-Qiao Chen, Sheng-Yuan Yu, Sheng-Li Guo, Ke Li, Mian-Wang He, Hai-Tao Wu, Jiang-Xia Qiu, Lei Zhang, Yu-Lin Wang, Xin Lou, Lin Ma
Purpose To investigate the topologic architecture of white matter connectivity networks in preschool-aged children with a diagnosis of autism spectrum disorder (ASD) versus typical development (TD). Materials and Methods Forty-two participants were enrolled, including 21 preschool children with ASD (14 male children and seven female children; mean age, 4.56 years ± 0.97 [standard deviation]) and 21 children with TD (11 males and 10 females; mean age, 5.13 years ± 0.82). The diagnosis of ASD was determined according to the Diagnostic and Statistical Manual of Mental Disorders Global Assessment of Functioning scores (mean score, 8...
March 27, 2018: Radiology
Yang Li, Xinqiang Gao, Biao Jie, Pew-Thian Yap, Min-Jeong Kim, Chong-Yaw Wee, Dinggang Shen
Hyper-connectivity network is a network where every edge is connected to more than two nodes, and can be naturally denoted using a hyper-graph. Hyper-connectivity brain network, either based on structural or functional interactions among the brain regions, has been used for brain disease diagnosis. However, the conventional hyper-connectivity network is constructed solely based on single modality data, ignoring potential complementary information conveyed by other modalities. The integration of complementary information from multiple modalities has been shown to provide a more comprehensive representation about the brain disruptions...
September 2017: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
Panlong Li, Han Shan, Shengxiang Liang, Binbin Nie, Shaofeng Duan, Qi Huang, Tianhao Zhang, Xi Sun, Ting Feng, Lin Ma, Baoci Shan, Demin Li, Hua Liu
Retrosplenial cortex (RSC) plays a key role in various cognitive functions. The fiber connectivity of RSC had been reported in rodent and primate studies by tracer injection methods To explore structural and functional connectivity of two sub-regions of RSC, Brodmann area (BA)29 and BA30, we constructed fiber connectivity networks of two sub-regions by diffusion tensor imaging (DTI) tractography based on diffusion magnetic resonance imaging (MRI) and functional connectivity networks by resting-state functional MRI...
March 9, 2018: Neuroscience Letters
Gaia Olivo, Francesco Latini, Lyle Wiemerslage, Elna-Marie Larsson, Helgi B Schiöth
Background : Neurovascular coupling is associated with white matter (WM) structural integrity, and it is regulated by specific subtypes of dopaminergic receptors. An altered activity of such receptors, highly expressed in reward-related regions, has been reported in carriers of obesity-risk alleles of the fat mass and obesity associated ( FTO ) gene. Among the reward-related regions, the thalamus and the nucleus accumbens are particularly vulnerable to blood pressure dysregulation due to their peculiar anatomo-vascular characteristics, and have been consistently reported to be altered in early-stage obesity...
2018: Frontiers in Human Neuroscience
Ilaria Boscolo Galazzo, Lorenza Brusini, Silvia Obertino, Mauro Zucchelli, Cristina Granziera, Gloria Menegaz
Recent tract-based analyses provided evidence for the exploitability of 3D-SHORE microstructural descriptors derived from diffusion MRI (dMRI) in revealing white matter (WM) plasticity. In this work, we focused on the main open issues left: (1) the comparative analysis with respect to classical tensor-derived indices, i.e., Fractional Anisotropy (FA) and Mean Diffusivity (MD); and (2) the ability to detect plasticity processes in gray matter (GM). Although signal modeling in GM is still largely unexplored, we investigated their sensibility to stroke-induced microstructural modifications occurring in the contralateral hemisphere...
2018: Frontiers in Neuroscience
Marialuisa Cavelti, Tilo Kircher, Arne Nagels, Werner Strik, Philipp Homan
Formal thought disorder (FTD) is a core feature of schizophrenia, a marker of illness severity and a predictor of outcome. The underlying neural mechanisms are still a matter of debate. This study aimed at 1) reviewing the literature on the neural correlates of FTD in schizophrenia, and 2) testing the hypothesis that FTD correlates with structural and functional aberrations in the language network. Medline, PsychInfo, and Embase were searched for neuroimaging studies, which applied a clinical measure to assess FTD in adults with schizophrenia and were published in English or German in peer-reviewed journals until December 2016...
March 3, 2018: Schizophrenia Research
Peiying Ruan, Morihiro Hayashida, Tatsuya Akutsu, Jean-Philippe Vert
BACKGROUND: Since many proteins become functional only after they interact with their partner proteins and form protein complexes, it is essential to identify the sets of proteins that form complexes. Therefore, several computational methods have been proposed to predict complexes from the topology and structure of experimental protein-protein interaction (PPI) network. These methods work well to predict complexes involving at least three proteins, but generally fail at identifying complexes involving only two different proteins, called heterodimeric complexes or heterodimers...
February 19, 2018: BMC Bioinformatics
Raluca Pascalau, Roxana Popa Stănilă, Silviu Sfrângeu, Bianca Szabo
BACKGROUND: The limbic tracts are involved in crucial cerebral functions such as memory, emotion and behavior. The complex architecture of the limbic circuit makes it harder to approach compared to other white matter networks. Our study aims to describe the three-dimensional anatomy of the limbic white matter by use of two complementary study methods, namely ex vivo fiber dissection and in vivo MRI based tractography. METHODS: Three fiber dissection protocols were performed using blunt wooden instruments and a surgical microscope on formalin fixed brains prepared according to the Klingler method...
February 28, 2018: World Neurosurgery
Olga Tymofiyeva, Eva Henje Blom, Tiffany C Ho, Colm G Connolly, Daniel Lindqvist, Owen M Wolkowitz, Jue Lin, Kaja Z LeWinn, Matthew D Sacchet, Laura K M Han, Justin P Yuan, Sarina P Bhandari, Duan Xu, Tony T Yang
BACKGROUND: Adolescent anxiety and depression are highly prevalent psychiatric disorders that are associated with altered molecular and neurocircuit profiles. Recently, increased mitochondrial DNA copy number (mtDNA-cn) has been found to be associated with several psychopathologies in adults, especially anxiety and depression. The associations between mtDNA-cn and anxiety and depression have not, however, been investigated in adolescents. Moreover, to date there have been no studies examining associations between mtDNA-cn and brain network alterations in mood disorders in any age group...
February 17, 2018: Journal of Affective Disorders
Betul Pamuk, Philip B Allen, Maria Victoria Fernandez-Serra
Nuclear quantum effects lead to an anomalous shift of the volume of hexagonal ice; heavy ice has a larger volume than light ice. Furthermore, this anomaly in ice increases with temperature and persists in liquid water up to the boiling point. To gain more insight, we study nuclear quantum effects on the density and compressibility of several ice-like structures and crystalline ice phases. By calculating the anisotropic contributions to the stain tensor, we analyze how the compressibility changes along different directions in hexagonal ice, and find that hexagonal ice is softer along the x-y plane than the z-direction...
February 28, 2018: Journal of Physical Chemistry. B
Javier Gomez-Pilar, Rodrigo de Luis-García, Alba Lubeiro, Nieves de Uribe, Jesús Poza, Pablo Núñez, Marta Ayuso, Roberto Hornero, Vicente Molina
Spectral entropy (SE) allows comparing task-related modulation of electroencephalogram (EEG) between patients and controls, i.e. spectral changes of the EEG associated to task performance. A SE modulation deficit has been replicated in different schizophrenia samples. To investigate the underpinnings of SE modulation deficits in schizophrenia, we applied graph-theory to EEG recordings during a P300 task and fractional anisotropy (FA) data from diffusion tensor imaging in 48 patients (23 first episodes) and 87 healthy controls...
2018: NeuroImage: Clinical
Woo Young Im, Ji Hye Ha, Eun Joo Kim, Keun-Ah Cheon, Jaeil Cho, Dong-Ho Song
Objective: It is known that many of the cognitive and social deficits associated with autism can arise from abnormal functional connectivity between brain networks. This aberrant functional connectivity in autism spectrum disorders (ASD) can be explained by impaired integrity of white matter tracts that link distant regions of the networks. Methods: We investigated white matter in 9 children with high-function autism (HFA) compared to 13 typically developing controls using diffusion tensor imaging (DTI)...
February 28, 2018: Psychiatry Investigation
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