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Brain Source Localization

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https://www.readbyqxmd.com/read/29028500/neural-network-topology-in-adhd-evidence-for-maturational-delay-and-default-mode-network-alterations
#1
T W P Janssen, A Hillebrand, A Gouw, K Geladé, R Van Mourik, A Maras, J Oosterlaan
OBJECTIVE: Attention-deficit/hyperactivity disorder (ADHD) has been associated with widespread brain abnormalities in white and grey matter, affecting not only local, but global functional networks as well. In this study, we explored these functional networks using source-reconstructed electroencephalography in ADHD and typically developing (TD) children. We expected evidence for maturational delay, with underlying abnormalities in the default mode network. METHODS: Electroencephalograms were recorded in ADHD (n=42) and TD (n=43) during rest, and functional connectivity (phase lag index) and graph (minimum spanning tree) parameters were derived...
September 23, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29026994/the-role-of-phasic-norepinephrine-modulations-during-task-switching-evidence-for-specific-effects-in-parietal-areas
#2
Nicole Wolff, Moritz Mückschel, Tjalf Ziemssen, Christian Beste
Cognitive flexibility is a major requirement for successful goal-directed behavior and their neurobiological underpinnings are becoming better understood. However, the role of the norepinephrine system during task switching is largely enigmatic, despite neurobiological considerations make it likely that the norepinephrine system likely plays an important role. Theoretical considerations also suggest that the norepinephrine system mainly modulates task-switching processes when these rely upon working memory mechanisms...
October 12, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/29026538/plasma-and-cerebrospinal-fluid-interleukin-1%C3%AE-during-lipopolysaccharide-induced-systemic-inflammation-in-ewes-implanted-or-not-with-slow-release-melatonin
#3
Janina Skipor, Marta Kowalewska, Aleksandra Szczepkowska, Anna Majewska, Tomasz Misztal, Marek Jalynski, Andrzej P Herman, Katarzyna Zabek
BACKGROUND: Interleukin-1β (IL-1β) is important mediator of inflammatory-induced suppression of reproductive axis at the hypothalamic level. At the beginning of inflammation, the main source of cytokines in the cerebrospinal fluid (CSF) is peripheral circulation, while over time, cytokines produced in the brain are more important. Melatonin has been shown to decrease pro-inflammatory cytokines concentration in the brain. In ewes, melatonin is used to advance the onset of a breading season...
2017: Journal of Animal Science and Biotechnology
https://www.readbyqxmd.com/read/29024165/clinical-yield-of-magnetoencephalography-distributed-source-imaging-in-epilepsy-a-comparison-with-equivalent-current-dipole-method
#4
Giovanni Pellegrino, Tanguy Hedrich, Rasheda Arman Chowdhury, Jeffery A Hall, Francois Dubeau, Jean-Marc Lina, Eliane Kobayashi, Christophe Grova
OBJECTIVE: Source localization of interictal epileptic discharges (IEDs) is clinically useful in the presurgical workup of epilepsy patients. It is usually obtained by equivalent current dipole (ECD) which localizes a point source and is the only inverse solution approved by clinical guidelines. In contrast, magnetic source imaging using distributed methods (dMSI) provides maps of the location and the extent of the generators, but its yield has not been clinically validated. We systematically compared ECD versus dMSI performed using coherent Maximum Entropy on the Mean (cMEM), a method sensitive to the spatial extent of the generators...
October 11, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29022597/genetic-effects-on-gene-expression-across-human-tissues
#5
Alexis Battle, Christopher D Brown, Barbara E Engelhardt, Stephen B Montgomery
Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci...
October 11, 2017: Nature
https://www.readbyqxmd.com/read/28990264/consistency-of-magnetoencephalographic-functional-connectivity-and-network-reconstruction-using-a-template-versus-native-mri-for-co-registration
#6
Linda Douw, Dagmar Nieboer, Cornelis J Stam, Prejaas Tewarie, Arjan Hillebrand
INTRODUCTION: Studies using functional connectivity and network analyses based on magnetoencephalography (MEG) with source localization are rapidly emerging in neuroscientific literature. However, these analyses currently depend on the availability of costly and sometimes burdensome individual MR scans for co-registration. We evaluated the consistency of these measures when using a template MRI, instead of native MRI, for the analysis of functional connectivity and network topology. METHODS: Seventeen healthy participants underwent resting-state eyes-closed MEG and anatomical MRI...
October 8, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28988244/evolution-of-sound-source-localization-circuits-in-the-nonmammalian-vertebrate-brainstem
#7
Peggy L Walton, Jakob Christensen-Dalsgaard, Catherine E Carr
The earliest vertebrate ears likely subserved a gravistatic function for orientation in the aquatic environment. However, in addition to detecting acceleration created by the animal's own movements, the otolithic end organs that detect linear acceleration would have responded to particle movement created by external sources. The potential to identify and localize these external sources may have been a major selection force in the evolution of the early vertebrate ear and in the processing of sound in the central nervous system...
2017: Brain, Behavior and Evolution
https://www.readbyqxmd.com/read/28983703/mapping-slow-waves-by-eeg-topography-and-source-localization-effects-of-sleep-deprivation
#8
Alessia Bersagliere, Roberto D Pascual-Marqui, Leila Tarokh, Peter Achermann
Slow waves are a salient feature of the electroencephalogram (EEG) during non-rapid eye movement (non-REM) sleep. The aim of this study was to assess the topography of EEG power and the activation of brain structures during slow wave sleep under normal conditions and after sleep deprivation. Sleep EEG recordings during baseline and recovery sleep after 40 h of sustained wakefulness were analyzed (eight healthy young men, 27 channel EEG). Power maps were computed for the first non-REM sleep episode (where sleep pressure is highest) in baseline and recovery sleep, at frequencies between 0...
October 5, 2017: Brain Topography
https://www.readbyqxmd.com/read/28981957/the-role-of-high-frequency-oscillations-in-epilepsy-surgery-planning
#9
REVIEW
David Gloss, Sarah J Nevitt, Richard Staba
BACKGROUND: Epilepsy is a serious brain disorder characterized by recurrent unprovoked seizures. Approximately two-thirds of seizures can be controlled with antiepileptic medications (Kwan 2000). For some of the others, surgery can completely eliminate or significantly reduce the occurrence of disabling seizures. Localization of epileptogenic areas for resective surgery is far from perfect, and new tools are being investigated to more accurately localize the epileptogenic zone (the zone of the brain where the seizures begin) and improve the likelihood of freedom from postsurgical seizures...
October 5, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28960497/using-spatiotemporal-source-separation-to-identify-prominent-features-in-multichannel-data-without-sinusoidal-filters
#10
Michael X Cohen
The number of simultaneously recorded electrodes in neuroscience is steadily increasing, providing new opportunities for understanding brain function, but also new challenges for appropriately dealing with the increase in dimensionality. Multivariate source-separation analysis methods have been particularly effective at improving signal-to-noise ratio while reducing the dimensionality of the data, and are widely used for cleaning, classifying, and source-localizing multichannel neural time series data. Most source-separation methods produce a spatial component (that is, a weighted combination of channels to produce one time series); here, this is extended to apply source-separation to a time series, with the idea of obtaining a weighted combination of successive time points, such that the weights are optimized to satisfy some criteria...
September 27, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28959193/the-brain-of-binge-drinkers-at-rest-alterations-in-theta-and-beta-oscillations-in-first-year-college-students-with-a-binge-drinking-pattern
#11
Eduardo López-Caneda, Fernando Cadaveira, Angeles Correas, Alberto Crego, Fernando Maestú, Socorro Rodríguez Holguín
Background: Previous studies have reported anomalous resting brain activity in the electroencephalogram (EEG) of alcoholics, often reflected as increased power in the beta and theta frequency bands. The effects of binge drinking, the most common pattern of excessive alcohol consumption during adolescence and youth, on brain activity at rest is still poorly known. In this study, we sought to assess the pattern of resting-state EEG oscillations in college-aged binge drinkers (BDs). Methods: Resting-state brain activity during eyes-open and eyes-closed conditions was recorded from 60 channels in 80 first-year undergraduate students (40 controls and 40 BDs)...
2017: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/28951350/estimating-cortical-column-sensory-networks-in-rodents-from-micro-electrocorticograph-%C3%AE-ecog-recordings
#12
Ricardo Pizarro, Tom Richner, Sarah Brodnick, Sanitta Thongpang, Justin Williams, Barry Van Veen
Micro-electrocorticograph (μECoG) arrays offer the flexibility to record local field potentials (LFPs) from the surface of the cortex, using high density electrodes that are sub-mm in diameter. Research to date has not provided conclusive evidence for the underlying signal generation of μECoG recorded LFPs, or if μECoG arrays can capture network activity from the cortex. We studied the pervading view of the LFP signal by exploring the spatial scale at which the LFP can be considered elemental. We investigated the underlying signal generation and ability to capture functional networks by implanting, μECoG arrays to record sensory-evoked potentials in four rats...
September 23, 2017: NeuroImage
https://www.readbyqxmd.com/read/28938855/eeg-resting-state-networks-microstates-source-localization
#13
Anna Custo, Dimitri van der Ville, William M Wells, Ioana M Tomescu, Christoph Michel
Using EEG to elucidate the spontaneous activation of brain resting state networks is non trivial as the signal of interest is of low amplitude and it is difficult to distinguish the underlying neural sources. Using the principles of electric field topographical analysis, it is possible to estimate the meta-stable states of the brain (i.e., the resting state topographies, so-called microstates). We estimated seven resting state topographies explaining the EEG dataset with k-means clustering (N=164, 256 electrodes)...
September 22, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28924008/primary-generators-of-visually-evoked-field-potentials-recorded-in-the-macaque-auditory-cortex
#14
Yoshinao Kajikawa, John F Smiley, Charles E Schroeder
Prior studies have reported "local" field potential (LFP) responses to faces in the macaque auditory cortex and have suggested that such face-LFPs may be substrates of audiovisual integration. However, while field potentials (FPs) may reflect the synaptic currents of neurons near the recording electrode, due to the use of a distant reference electrode, they often reflect those of synaptic activity occurring in distant sites as well. Thus, FP recordings within a given brain region (e.g., auditory cortex) may be "contaminated" by activity generated elsewhere in the brain...
September 18, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28921735/three-shades-of-grey-detecting-brain-abnormalities-in-children-with-autism-by-using-source-voxel-and-surface-based-morphometry
#15
Edoardo Pappaianni, Roma Siugzdaite, Sofie Vettori, Paola Venuti, Remo Job, Alessandro Grecucci
Autistic spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interactions, communication and stereotyped behavior. Recent evidence from neuroimaging supports the hypothesis that ASD deficits in adults may be related to abnormalities in a specific frontal-temporal network (Autism-specific Structural Network, ASN). To see whether these results extend to younger children and to better characterize these abnormalities, we applied three morphometric methods on brain grey matter of children with and without ASD...
September 16, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28920903/brain-control-of-an-external-device-by-extracting-the-highest-force-related-contents-of-local-field-potentials-in-freely-moving-rats
#16
Abed Khorasani, Reza Foodeh, Vahid Shalchyan, Mohammad Reza Daliri
A local field potential (LFP) signal is an alternative source to neural action potentials for decoding kinematic and kinetic information from the brain. Here we demonstrate that better extraction of force-related features from multichannel LFPs improves the accuracy of force decoding. We propose that applying canonical correlation analysis (CCA) filter on the envelopes of separate frequency bands (band-specific CCA) seperates non- task related information from the LFPs. The decoding accuracy of the continuous force signal based on the proposed method were compared with three feature reduction methods: 1) Band-specific principal component analysis (bandspecific PCA) method that extract the components which leads to maximum variance from envelopes of different frequency bands, 2) Correlation coefficient-based (CC-based) feature reduction that selects the best features from the envelopes sorted based on the absolute correlation coefficient between each envelope and the target force signal and 3) Mutual information -based (MI-based) feature reduction that selects the best features from the envelopes sorted based on the mutual information between each envelope and output force signal...
September 12, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28920893/a-functional-genetic-scheme-for-seizure-forecasting-in-canine-epilepsy
#17
E Bou Assi, D K Nguyen, S Rihana, M Sawan
OBJECTIVE: The objective of this work is the development of an accurate seizure forecasting algorithm that considers brain's functional connectivity for electrode selection. METHODS: We start by proposing Kmeans-directed transfer function, an adaptive functional connectivity method intended for seizure onset zone localization in bilateral intracranial EEG recordings. Electrodes identified as seizure activity sources and sinks are then used to implement a seizure-forecasting algorithm on long-term continuous recordings in dogs with naturallyoccurring epilepsy...
September 13, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28920892/computationally-efficient-algorithms-for-sparse-dynamic-solutions-to-the-eeg-source-localization-problem
#18
Elvira Pirondini, Behtash Babadi, Gabriel Obregon-Henao, Camilo Lamus, Wasim Q Malik, Matti S Hamalainen, Patrick L Purdon
OBJECTIVE: Electroencephalography (EEG) and magnetoencephalography (MEG) non-invasively record scalp electromagnetic fields generated by cerebral currents, revealing millisecond-level brain dynamics useful for neuroscience and clinical applications. Estimating the currents that generate these fields, i.e., source localization, is an ill-conditioned inverse problem. Solutions to this problem have focused on spatial continuity constraints, dynamic modeling, or sparsity constraints. The combination of these key ideas could offer significant performance improvements, but substantial computational costs pose a challenge for practical application of such approaches...
September 14, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28919388/altered-brain-functional-connectivity-induced-by-physical-exercise-may-improve-neuropsychological-functions-in-patients-with-benign-epilepsy
#19
Gyan Raj Koirala, Dongpyo Lee, Soyong Eom, Nam-Young Kim, Heung Dong Kim
OBJECTIVE: The objective of this study was to elucidate alteration in functional connectivity (FC) in patients with benign epilepsy with centrotemporal spikes (BECTS) as induced by physical exercise therapy and their correlation to the neuropsychological (NP) functions. METHODS: We analyzed 115 artifact- and spike-free 2-second epochs extracted from resting state EEG recordings before and after 5weeks of physical exercise in eight patients with BECTS. The exact Low Resolution Electromagnetic Tomography (eLORETA) was used for source reconstruction...
September 15, 2017: Epilepsy & Behavior: E&B
https://www.readbyqxmd.com/read/28917446/amplitude-modulation-rate-dependent-topographic-organization-of-the-auditory-steady-state-response-in-human-auditory-cortex
#20
Nathan Weisz, Chrysoula Lithari
Periodic modulations of an acoustic feature, such as amplitude over a certain frequency range, leads to phase locking of neural responses to the envelope of the modulation. Using electrophysiological methods this neural activity pattern, also called the auditory steady-state response (aSSR), is visible following frequency transformation of the evoked response as a clear spectral peak at the modulation frequency. Despite several studies employing the aSSR that show, for example, strongest responses for ∼40 Hz and an overall right-hemispheric dominance, it has not been investigated so far to what extent within auditory cortex different modulation frequencies elicit aSSRs at a homogenous source or whether the localization of the aSSR is topographically organized in a systematic manner...
September 11, 2017: Hearing Research
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