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Brain Source Localization

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https://www.readbyqxmd.com/read/28327613/robust-and-fast-characterization-of-oct-based-optical-attenuation-using-a-novel-frequency-domain-algorithm-for-brain-cancer-detection
#1
Wu Yuan, Carmen Kut, Wenxuan Liang, Xingde Li
Cancer is known to alter the local optical properties of tissues. The detection of OCT-based optical attenuation provides a quantitative method to efficiently differentiate cancer from non-cancer tissues. In particular, the intraoperative use of quantitative OCT is able to provide a direct visual guidance in real time for accurate identification of cancer tissues, especially these without any obvious structural layers, such as brain cancer. However, current methods are suboptimal in providing high-speed and accurate OCT attenuation mapping for intraoperative brain cancer detection...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28326645/local-changes-in-the-wake-electroencephalogram-precedes-lane-departures
#2
Christer Ahlstrom, Sabina Jansson, Anna Anund
The objective of this exploratory study is to investigate if lane departures are associated with local sleep, measured via source-localized electroencephalography (EEG) theta power in the 5-9 Hz frequency range. Thirty participants drove in an advanced driving simulator, resulting in 135 lane departures at high levels of self-reported sleepiness. These lane departures were compared to matching non-departures at the same sleepiness level within the same individual. There was no correspondence between lane departures and global theta activity...
March 22, 2017: Journal of Sleep Research
https://www.readbyqxmd.com/read/28323161/seeg-dipole-source-localization-based-on-an-empirical-bayesian-approach-taking-into-account-forward-model-uncertainties
#3
S Le Cam, R Ranta, V Caune, G Korats, L Koessler, L Maillard, V Louis-Dorr
Electromagnetic brain source localization consists in the inversion of a forward model based on a limited number of potential measurements. A wide range of methods has been developed to regularize this severely ill-posed problem and to reduce the solution space, imposing spatial smoothness, anatomical constraint or sparsity of the activated source map. This last criteria, based on physiological assumptions stating that in some particular events (e.g., epileptic spikes, evoked potential) few focal area of the brain are simultaneously actives, has gained more and more interest...
March 17, 2017: NeuroImage
https://www.readbyqxmd.com/read/28322859/decoding-the-encoding-of-functional-brain-networks-an-fmri-classification-comparison-of-non-negative-matrix-factorization-nmf-independent-component-analysis-ica-and-sparse-coding-algorithms
#4
Jianwen Xie, Pamela K Douglas, Ying Nian Wu, Arthur L Brody, Ariana E Anderson
BACKGROUND: Brain networks in fMRI are typically identified using spatial independent component analysis (ICA), yet other mathematical constraints provide alternate biologically-plausible frameworks for generating brain networks. Non-negative Matrix Factorization (NMF) would suppress negative BOLD signal by enforcing positivity. Spatial sparse coding algorithms (L1 Regularized Learning and K-SVD) would impose local specialization and a discouragement of multitasking, where the total observed activity in a single voxel originates from a restricted number of possible brain networks...
March 17, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28303098/ielectrodes-a-comprehensive-open-source-toolbox-for-depth-and-subdural-grid-electrode-localization
#5
Alejandro O Blenkmann, Holly N Phillips, Juan P Princich, James B Rowe, Tristan A Bekinschtein, Carlos H Muravchik, Silvia Kochen
The localization of intracranial electrodes is a fundamental step in the analysis of invasive electroencephalography (EEG) recordings in research and clinical practice. The conclusions reached from the analysis of these recordings rely on the accuracy of electrode localization in relationship to brain anatomy. However, currently available techniques for localizing electrodes from magnetic resonance (MR) and/or computerized tomography (CT) images are time consuming and/or limited to particular electrode types or shapes...
2017: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/28300640/consistency-of-eeg-source-localization-and-connectivity-estimates
#6
Keyvan Mahjoory, Vadim V Nikulin, Loïc Botrel, Klaus Linkenkaer-Hansen, Marco M Fato, Stefan Haufe
As the EEG inverse problem does not have a unique solution, the sources reconstructed from EEG and their connectivity properties depend on forward and inverse modeling parameters such as the choice of an anatomical template and electrical model, prior assumptions on the sources, and further implementational details. In order to use source connectivity analysis as a reliable research tool, there is a need for stability across a wider range of standard estimation routines. Using resting state EEG recordings of N=65 participants acquired within two studies, we present the first comprehensive assessment of the consistency of EEG source localization and functional/effective connectivity metrics across two anatomical templates (ICBM152 and Colin27), three electrical models (BEM, FEM and spherical harmonics expansions), three inverse methods (WMNE, eLORETA and LCMV), and three software implementations (Brainstorm, Fieldtrip and our own toolbox)...
March 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/28281494/role-of-magnetoencephalography-and-stereo-electroencephalography-in-the-presurgical-evaluation-in-patients-with-drug-resistant-epilepsy
#7
REVIEW
V Jayabal, Ashok Pillai, S Sinha, N Mariyappa, P Satishchandra, S Gopinath, Kurupath Radhakrishnan
In selected patients with drug-resistant focal epilepsies (DRFE), who otherwise are likely to be excluded from epilepsy surgery (ES) because of the absence of a magnetic resonance imaging (MRI)-demonstrable lesion or discordant anatomo-electro-clinical (AEC) data, magnetoencephalography (MEG) may help to generate an AEC hypothesis and stereo-electroencephalography (SEEG) may help to verify the hypothesis and proceed with ES. The sensitivity of MEG is much better in localizing the spiking zone in relation to lateral temporal and extratemporal cortical regions compared to the mesial temporal structures...
2017: Neurology India
https://www.readbyqxmd.com/read/28279193/human-mesenchymal-stromal-cells-inhibit-tumor-growth-in-orthotopic-glioblastoma-xenografts
#8
Simone Pacioni, Quintino Giorgio D'Alessandris, Stefano Giannetti, Liliana Morgante, Valentina Coccè, Arianna Bonomi, Mariachiara Buccarelli, Luisa Pascucci, Giulio Alessandri, Augusto Pessina, Lucia Ricci-Vitiani, Maria Laura Falchetti, Roberto Pallini
BACKGROUND: Mesenchymal stem/stromal cells (MSCs) represent an attractive tool for cell-based cancer therapy mainly because of their ability to migrate to tumors and to release bioactive molecules. However, the impact of MSCs on tumor growth has not been fully established. We previously demonstrated that murine MSCs show a strong tropism towards glioblastoma (GBM) brain xenografts and that these cells are able to uptake and release the chemotherapeutic drug paclitaxel (PTX), maintaining their tropism towards the tumor...
March 9, 2017: Stem Cell Research & Therapy
https://www.readbyqxmd.com/read/28275720/hetereogeneity-in-neuronal-intrinsic-properties-a-possible-mechanism-for-hub-like-properties-of-the-rat-anterior-cingulate-cortex-during-network-activity
#9
Natalie E Adams, Jason S Sherfey, Nancy J Kopell, Miles A Whittington, Fiona E N LeBeau
The anterior cingulate cortex (ACC) is vital for a range of brain functions requiring cognitive control and has highly divergent inputs and outputs, thus manifesting as a hub in connectomic analyses. Studies show diverse functional interactions within the ACC are associated with network oscillations in the β (20-30 Hz) and γ (30-80 Hz) frequency range. Oscillations permit dynamic routing of information within cortex, a function that depends on bandpass filter-like behavior to selectively respond to specific inputs...
January 2017: ENeuro
https://www.readbyqxmd.com/read/28271441/modulation-of-locus-coeruleus-activity-by-novel-oddball-stimuli
#10
Ruth M Krebs, Haeme R P Park, Klaas Bombeke, Carsten N Boehler
It has long been known from animal literature that the locus coeruleus (LC), the source region of noradrenergic neurons in the brain, is sensitive to unexpected, novel, and other salient events. In humans, however, direct assessment of LC activity has proven to be challenging due to its small size and difficult localization, which is why noradrenergic activity has often been assessed using more indirect measures such as electroencephalography (EEG) and pupil recordings. Here, we combined high-resolution functional magnetic resonance imaging (fMRI) with a special anatomical sequence to assess neural activity in the LC in response to different types of salient stimuli in an oddball paradigm (novel neutral oddballs, novel emotional oddballs, and familiar target oddballs)...
March 7, 2017: Brain Imaging and Behavior
https://www.readbyqxmd.com/read/28269289/multi-direction-hand-movement-classification-using-eeg-based-source-space-analysis
#11
Vikram Shenoy Handiru, A P Vinod, Cuntai Guan
Recent advances in the brain-computer interfaces (BCIs) have demonstrated the inference of movement related activity using non-invasive EEG. However, most of the sensorspace approaches that study sensorimotor rhythms using EEG do not reveal the underlying neurophysiological phenomenon while executing or imagining the movement with finer control. Therefore, there is a need to examine feature extraction techniques in the cortical source space which can provide more information about the task compared to sensor-space...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28269283/kernel-temporal-enhancement-approach-for-loreta-source-reconstruction-using-eeg-data
#12
Cristian A Torres-Valencia, M Claudia Joana Santamaria, Mauricio A Alvarez
Reconstruction of brain sources from magnetoencephalography and electroencephalography (M/EEG) data is a well known problem in the neuroengineering field. A inverse problem should be solved and several methods have been proposed. Low Resolution Electromagnetic Tomography (LORETA) and the different variations proposed as standardized LORETA (sLORETA) and the standardized weighted LORETA (swLORETA) have solved the inverse problem following a non-parametric approach, that is by setting dipoles in the whole brain domain in order to estimate the dipole positions from the M/EEG data and assuming some spatial priors...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28269176/multivariate-autoregressive-model-constrained-by-anatomical-connectivity-to-reconstruct-focal-sources
#13
Brahim Belaoucha, Mouloud Kachouane, Theodore Papadopoulo
In this paper, we present a framework to reconstruct spatially localized sources from Magnetoencephalography (MEG)/Electroencephalography (EEG) using spatiotemporal constraint. The source dynamics are represented by a Multivariate Autoregressive (MAR) model whose matrix elements are constrained by the anatomical connectivity obtained from diffusion Magnetic Resonance Imaging (dMRI). The framework assumes that the whole brain dynamic follows a constant MAR model in a time window of interest. The source activations and the MAR model parameters are estimated iteratively...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268291/comparison-of-imaging-modalities-and-source-localization-algorithms-in-locating-the-induced-activity-during-deep-brain-stimulation-of-the-stn
#14
K G Mideksa, A Singh, N Hoogenboom, H Hellriegel, H Krause, A Schnitzler, G Deuschl, J Raethjen, G Schmidt, M Muthuraman
One of the most commonly used therapy to treat patients with Parkinson's disease (PD) is deep brain stimulation (DBS) of the subthalamic nucleus (STN). Identifying the most optimal target area for the placement of the DBS electrodes have become one of the intensive research area. In this study, the first aim is to investigate the capabilities of different source-analysis techniques in detecting deep sources located at the sub-cortical level and validating it using the a-priori information about the location of the source, that is, the STN...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268290/graph-fractional-order-total-variation-eeg-source-reconstruction
#15
Ying Li, Jing Qin, Stanley Osher, Wentai Liu
EEG source imaging is able to reconstruct sources in the brain from scalp measurements with high temporal resolution. Due to the limited number of sensors, it is very challenging to locate the source accurately with high spatial resolution. Recently, several total variation (TV) based methods have been proposed to explore sparsity of the source spatial gradients, which is based on the assumption that the source is constant at each subregion. However, since the sources have more complex structures in practice, these methods have difficulty in recovering the current density variation and locating source peaks...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28260394/evidence-for-behaviorally-segregated-spatio-temporally-overlapping-subnetworks-in-phantom-sound-perception
#16
Anusha Mohan, Nicole Moreno, Jae-Jin Song, Dirk De Ridder, Sven Vanneste
One of the most intriguing questions in neuroscience is to understand the mechanism of information transfer between different brain areas. Recently, network theory has gained traction and is at the forefront of providing a possible explanation to not only the mechanism of information transfer, but also in the identification of different neuropathologies. The perception of a phantom ringing in the ear called tinnitus, similar to other neuropathologies, has been shown to be accompanied by aberrant functional connectivity between different brain areas...
March 6, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28257807/temporal-and-spatial-localization-of-prediction-error-signals-in-the-visual-brain
#17
Patrick Johnston, Jonathan Robinson, Athanasios Kokkinakis, Samuel Ridgeway, Michael Simpson, Sam Johnson, Jordy Kaufman, Andrew W Young
It has been suggested that the brain pre-empts changes in the environment through generating predictions, although real-time electrophysiological evidence of prediction violations in the domain of visual perception remain elusive. In a series of experiments we showed participants sequences of images that followed a predictable implied sequence or whose final image violated the implied sequence. Through careful design we were able to use the same final image transitions across predictable and unpredictable conditions, ensuring that any differences in neural responses were due only to preceding context and not to the images themselves...
February 28, 2017: Biological Psychology
https://www.readbyqxmd.com/read/28256510/local-entrainment-of-oscillatory-activity-induced-by-direct-brain-stimulation-in-humans
#18
Julià L Amengual, Marine Vernet, Claude Adam, Antoni Valero-Cabré
In a quest for direct evidence of oscillation entrainment, we analyzed intracerebral electroencephalographic recordings obtained during intracranial electrical stimulation in a cohort of three medication-resistant epilepsy patients tested pre-surgically. Spectral analyses of non-epileptogenic cerebral sites stimulated directly with high frequency electrical bursts yielded episodic local enhancements of frequency-specific rhythmic activity, phase-locked to each individual pulse. These outcomes reveal an entrainment of physiological oscillatory activity within a frequency band dictated by the rhythm of the stimulation source...
March 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28242317/studying-brain-microstructure-with-magnetic-susceptibility-contrast-at-high-field
#19
Jeff H Duyn
A rapidly developing application of high field MRI is the study of brain anatomy and function with contrast based on the magnetic susceptibility of tissues. To study the subtle variations in susceptibility contrast between tissues and with changes in brain activity, dedicated scan techniques such as susceptibility-weighted MRI and blood-oxygen level dependent functional MRI have been developed. Particularly strong susceptibility contrast has been observed with systems that operate at 7T and above, and their recent widespread use has led to an improved understanding of contributing sources and mechanisms...
February 24, 2017: NeuroImage
https://www.readbyqxmd.com/read/28235893/single-neurons-in-the-avian-auditory-cortex-encode-individual-identity-and-propagation-distance-in-naturally-degraded-communication-calls
#20
Solveig C Mouterde, Julie E Elie, Nicolas Mathevon, Frédéric E Theunissen
One of the most complex tasks performed by sensory systems is "scene analysis": the interpretation of complex signals as behaviorally relevant objects. The study of this problem, universal to species and sensory modalities, is particularly challenging in audition, where sounds from various sources and localizations, degraded by propagation through the environment, sum to form a single acoustical signal. Here we investigated in a songbird model, the zebra finch, the neural substrate for ranging and identifying a single source...
February 24, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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