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dynamic brain connectivity

John D Murray, Murat Demirtaş, Alan Anticevic
Noninvasive neuroimaging has revolutionized the study of the organization of the human brain and how its structure and function are altered in psychiatric disorders. A critical explanatory gap lies in our mechanistic understanding of how systems-level neuroimaging biomarkers emerge from underlying synaptic-level perturbations associated with a disease state. We describe an emerging computational psychiatry approach leveraging biophysically based computational models of large-scale brain dynamics and their potential integration with clinical and pharmacological neuroimaging...
July 19, 2018: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
James R Riehl, Ben J Palanca, ShiNung Ching
Characterizing anesthesia-induced alterations to brain network dynamics provides a powerful framework to understand the neural mechanisms of unconsciousness. To this end, increased attention has been directed at how anesthetic drugs alter the functional connectivity between brain regions as defined through neuroimaging. However, the effects of anesthesia on temporal dynamics at functional network scales is less well understood. Here, we examine such dynamics in view of the free-energy principle, which postulates that brain dynamics tend to promote lower energy (more organized) states...
2018: Network neuroscience
Ahmet S Ozcan, Mehmet S Ozcan
Structural plasticity, characterized by the formation and elimination of synapses, plays a big role in learning and long-term memory formation in the brain. The majority of the synapses in the neocortex occur between the axonal boutons and dendritic spines. Therefore, understanding the dynamics of the dendritic spine growth and elimination can provide key insights to the mechanisms of structural plasticity. In addition to learning and memory formation, the connectivity of neural networks affects cognition, perception, and behavior...
2018: Frontiers in Synaptic Neuroscience
Fadi N Karameh, Ziad Nahas
Model-based network discovery measures, such as the brain effective connectivity, require fitting of generative process models to measurements obtained from key areas across the network. For distributed dynamic phenomena, such as generalized seizures and slow-wave sleep, studying effective connectivity from real-time recordings is significantly complicated since (i) outputs from only a subnetwork can be practically measured, and (ii) exogenous subnetwork inputs are unobservable. Model fitting, therefore, constitutes a challenging blind module identification or model inversion problem for finding both the parameters and the many unknown inputs of the subnetwork...
August 4, 2018: Brain Topography
L J Gabard-Durnam, J O'Muircheartaigh, H Dirks, D C Dean, N Tottenham, S Deoni
Although the amygdala's role in shaping social behavior is especially important during early post-natal development, very little is known of amygdala functional development before childhood. To address this gap, this study uses resting-state fMRI to examine early amygdalar functional network development in a cross-sectional sample of 80 children from 3-months to 5-years of age. Whole brain functional connectivity with the amygdala, and its laterobasal and superficial sub-regions, were largely similar to those seen in older children and adults...
July 21, 2018: Developmental Cognitive Neuroscience
Catie Chang, Shella Keilholz, Robyn Miller, Mark Woolrich
No abstract text is available yet for this article.
July 31, 2018: NeuroImage
Cátia F Lourenço, Ana Ledo, Miguel Caetano, Rui M Barbosa, João Laranjinha
Neurovascular and neurometabolic coupling are critical and complex processes underlying brain function. Perturbations in the regulation of these processes are, likely, early dysfunctional alterations in pathological brain aging and age-related neurodegeneration. Evidences support the role of nitric oxide (•NO) as a key messenger both in neurovascular coupling, by signaling from neurons to blood vessels, and in neurometabolic coupling, by modulating O2 utilization by mitochondria. In the present study, we investigated the functionality of neurovascular and neurometabolic coupling in connection to •NO signaling and in association to cognitive performance during aging...
2018: Frontiers in Physiology
Weina Li, Jiuquan Zhang, Chaoyang Zhou, Wensheng Hou, Jun Hu, Hua Feng, Xiaolin Zheng
Purpose: Amyotrophic lateral sclerosis (ALS) is a motor neuro-degenerative disorder that also damages extra-motor neural pathways. A significant proportion of existing evidence describe alterations in the strengths of functional connectivity, whereas the changes in the density of these functional connections have not been explored. Therefore, our study seeks to identify ALS-induced alternations in the resting-state functional connectivity density (FCD). Methods: Two groups comprising of 38 ALS patients and 35 healthy participants (age and gender matched) were subjected to the resting-state functional magnetic resonance imaging (MRI) scanning...
2018: Frontiers in Aging Neuroscience
Noriya Watanabe, Jamil P Bhanji, Hideki Ohira, Mauricio R Delgado
Preparing for a challenging task can increase physiological arousal, in particular when potential incentives are large (e.g., a solo musical performance in front of an audience). Here, we examine how potential reward and its influence on arousal, measured by pupil dynamics, are represented in the brain while preparing for a challenging task. We further ask how neural representations during preparation relate to actual performance. Trials resulting in performance failure were characterized by increased pupil dilation as a function of increasing reward magnitude during preparation...
July 27, 2018: Cerebral Cortex
Saber Sami, Nitin Williams, Laura E Hughes, Thomas E Cope, Timothy Rittman, Ian T S Coyle-Gilchrist, Richard N Henson, James B Rowe
The disruption of brain networks is characteristic of neurodegenerative dementias. However, it is controversial whether changes in connectivity reflect only the functional anatomy of disease, with selective vulnerability of brain networks, or the specific neurophysiological consequences of different neuropathologies within brain networks. We proposed that the oscillatory dynamics of cortical circuits reflect the tuning of local neural interactions, such that different pathologies are selective in their impact on the frequency spectrum of oscillations, whereas clinical syndromes reflect the anatomical distribution of pathology and physiological change...
August 1, 2018: Brain: a Journal of Neurology
Jamila Andoh, Reiko Matsushita, Robert J Zatorre
Non-invasive brain stimulation (NIBS) has been widely used as a research tool to modulate cortical excitability of motor as well as non-motor areas, including auditory or language-related areas. NIBS, especially transcranial magnetic stimulation (TMS) and transcranial direct current stimulation, have also been used in clinical settings, with however variable therapeutic outcome, highlighting the need to better understand the mechanisms underlying NIBS techniques. TMS was initially used to address causality between specific brain areas and related behavior, such as language production, providing non-invasive alternatives to lesion studies...
2018: Frontiers in Neuroscience
Md Faijul Amin, Sergey M Plis, Adam Chekroud, Devon Hjelm, Eswar Damaraju, Hyo Jong Lee, Juan R Bustillo, KyungHyun Cho, Godfrey D Pearlson, Vince D Calhoun
This work presents a novel approach to finding linkage/association between multimodal brain imaging data, such as structural MRI (sMRI) and functional MRI (fMRI). Motivated by the machine translation domain, we employ a deep learning model, and consider two different imaging views of the same brain like two different languages conveying some common facts. That analogy enables finding linkages between two modalities. The proposed translation-based fusion model contains a computing layer that learns "alignments" (or links) between dynamic connectivity features from fMRI data and static gray matter patterns from sMRI data...
July 25, 2018: NeuroImage
Zareen Amtul, Carmen Frías, Jasmine Randhawa, David J Hill, Edith J Arany
The hippocampus, a brain region vital for memory and learning, is sensitive to the damage caused by ischemic/hypoxic stroke and is one of the main regions affected by Alzheimer's disease. The pathological changes that might occur in the hippocampus and its connections, because of cerebral injury in a distant brain region, such as the striatum, have not been examined. Therefore, in the present study, we evaluated the combined effects of endothelin-1-induced ischemia (ET1) in the striatum and β-amyloid (Aβ) toxicity on hippocampal pathogenesis, dictated by the anatomical and functional intra- and inter-regional hippocampal connections to the striatum...
July 28, 2018: Molecular Neurobiology
Michelle N Servaas, Claire Kos, Nicolás Gravel, Remco J Renken, Jan-Bernard C Marsman, Marie-José van Tol, André Aleman
The aim of this study was to investigate whether apathy in schizophrenia is associated with rigidity in behavior and brain functioning. To this end, we studied associations between variability in dynamic functional connectivity (DFC) in relevant functional brain networks, apathy, and variability in physical activity in schizophrenia. Thirty-one patients with schizophrenia, scoring high on apathy, were included and wore an actigraph. Activity variability was calculated on the activity counts using the root of the Mean Squared Successive Difference (MSSD)...
July 24, 2018: Schizophrenia Bulletin
Suprateek Kundu, Jin Ming, Jordan Pierce, Jennifer McDowell, Ying Guo
A common assumption in the study of brain functional connectivity is that the brain network is stationary. However it is increasingly recognized that the brain organization is prone to variations across the scanning session, fueling the need for dynamic connectivity approaches. One of the main challenges in developing such approaches is that the frequency and change points for the brain organization are unknown, with these changes potentially occurring frequently during the scanning session. In order to provide greater power to detect rapid connectivity changes, we propose a fully automated two-stage approach which pools information across multiple subjects to estimate change points in functional connectivity, and subsequently estimates the brain networks within each state phase lying between consecutive change points...
July 23, 2018: NeuroImage
Seyed Amir Hosseini, Abbas Sohrabpour, Mehmet Akcakaya, Bin He
: Adaptive beamformer methods, which have been extensively used for functional brain imaging using EEG/MEG signals, are sensitive to model mismatches. We propose a robust minimum variance beamformer (RMVB) technique, which explicitly incorporates the uncertainty of the lead field matrix into estimation of spatial-filter weights that are subsequently used to perform the imaging. : The uncertainty of the lead field is modeled by ellipsoids in the RMVB method; these hyper-ellipsoids (ellipsoids in higher dimensions) define regions of uncertainty for a given nominal lead field vector...
July 24, 2018: IEEE Transactions on Bio-medical Engineering
László Tóth, Dávid Szöllősi, Katalin Kis-Petik, István Adorján, Ferenc Erdélyi, Mihály Kálmán
The immediate alterations following lesions cannot be investigated by using fixed tissues. Here, we employed two-photon microscopy to study the alterations to the permeability of blood-brain barrier and to glio-vascular connections in vivo during the first minutes following cortical lesions in mice. Four models were used: (1) cryogenic lesion, (2) photodisruption using laser pulses, (3) photothrombosis, and (4) bilateral carotid ligation. Sulforhodamine101 was used for supravital labeling of astrocytes and dextran-bound fluorescein isothiocyanate for the assessment of extravasation...
July 26, 2018: Journal of Histochemistry and Cytochemistry: Official Journal of the Histochemistry Society
Sebastian Moguilner, Adolfo M García, Ezequiel Mikulan, Eugenia Hesse, Indira García-Cordero, Margherita Melloni, Sabrina Cervetto, Cecilia Serrano, Eduar Herrera, Pablo Reyes, Diana Matallana, Facundo Manes, Agustín Ibáñez, Lucas Sedeño
The search for biomarkers of neurodegenerative diseases via fMRI functional connectivity (FC) research has yielded inconsistent results. Yet, most FC studies are blind to non-linear brain dynamics. To circumvent this limitation, we developed a "weighted Symbolic Dependence Metric" (wSDM) measure. Using symbolic transforms, we factor in local and global temporal features of the BOLD signal to weigh a robust copula-based dependence measure by symbolic similarity, capturing both linear and non-linear associations...
July 25, 2018: Scientific Reports
Gojko Žarić, Inge Timmers, Patty Gerretsen, Gorka Fraga González, Jurgen Tijms, Maurits W van der Molen, Leo Blomert, Milene Bonte
Atypical structural properties of the brain's white matter bundles have been associated with failing reading acquisition in developmental dyslexia. Because these white matter properties may show dynamic changes with age and orthographic depth, we examined fractional anisotropy (FA) along 16 white matter tracts in 8- to 11-year-old dyslexic (DR) and typically reading (TR) children learning to read in a fairly transparent orthography (Dutch). Our results showed higher FA values in the bilateral anterior thalamic radiations of DRs and FA values of the left thalamic radiation scaled with behavioral reading-related scores...
2018: Frontiers in Psychology
Grégoire Vergotte, Stéphane Perrey, Muthuraman Muthuraman, Stefan Janaqi, Kjerstin Torre
In behavioral neuroscience, the adaptability of humans facing different constraints has been addressed on one side at the brain level, where a variety of functional networks dynamically support the same performance, and on the other side at the behavioral level, where fractal properties in sensorimotor variables have been considered as a hallmark of adaptability. To bridge the gap between the two levels of observation, we have jointly investigated the changes of network connectivity in the sensorimotor cortex assessed by modularity analysis and the properties of motor variability assessed by multifractal analysis during a prolonged tapping task...
2018: Frontiers in Physiology
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