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Brain Source Localization

Yongtian He, Trieu Phat Luu, Kevin Nathan, Sho Nakagome, Jose L Contreras-Vidal
We present a mobile brain-body imaging (MoBI) dataset acquired during treadmill walking in a brain-computer interface (BCI) task. The data were collected from eight healthy subjects, each having three identical trials. Each trial consisted of three conditions: standing, treadmill walking, and treadmill walking with a closed-loop BCI. During the BCI condition, subjects used their brain activity to control a virtual avatar on a screen to walk in real-time. Robust procedures were designed to record lower limb joint angles (bilateral hip, knee, and ankle) using goniometers synchronized with 60-channel scalp electroencephalography (EEG)...
April 24, 2018: Scientific Data
Dmitry V Zaretsky, Andrej A Romanovsky, Maria V Zaretskaia, Yaroslav I Molkov
Tissue temperature increases, when oxidative metabolism is boosted. The source of nutrients and oxygen for this metabolism is the blood. The blood also cools down the tissue, and this is the only cooling mechanism, when direct dissipation of heat from the tissue to the environment is insignificant, e.g. , in the brain. While this concept is relatively simple, it has not been described quantitatively. The purpose of the present work was to answer two questions: 1) to what extent can oxidative metabolism make the organ tissue warmer than the body core, and, 2) how quickly are changes in the local metabolism reflected in the temperature of the tissue? Our theoretical analysis demonstrates that, at equilibrium, given that heat exchange with the organ is provided by the blood, the temperature difference between the organ tissue and the arterial blood is proportional to the arteriovenous difference in oxygen content, does not depend on the blood flow, and cannot exceed 1...
2018: Temperature: Multidisciplinary Biomedical Journal
Dardo Tomasi, Nora D Volkow
The origin of the "resting-state" brain activity recorded with functional magnetic resonance imaging (fMRI) is still uncertain. Here we provide evidence for the neurovascular origins of the amplitude of the low-frequency fluctuations (ALFF) and the local functional connectivity density (lFCD) by comparing them with task-induced blood-oxygen level dependent (BOLD) responses, which are considered a proxy for neuronal activation. Using fMRI data for 2 different tasks (Relational and Social) collected by the Human Connectome Project in 426 healthy adults, we show that ALFF and lFCD have linear associations with the BOLD response...
April 13, 2018: Cerebral Cortex
Angelica Quercia, Filippo Zappasodi, Giorgia Committeri, Michele Ferrara
Sleep and wakefulness are no longer to be considered as discrete states. During wakefulness brain regions can enter a sleep-like state (off-periods) in response to a prolonged period of activity (local use-dependent sleep). Similarly, during nonREM sleep the slow-wave activity, the hallmark of sleep plasticity, increases locally in brain regions previously involved in a learning task. Recent studies have demonstrated that behavioral performance may be impaired by off-periods in wake in task-related regions...
2018: Frontiers in Human Neuroscience
Simeng Zhang, Allison T Connolly, Lauren Madden, Jerrold L Vitek, Matthew D Johnson
Local field potential (LFP) recordings along a deep brain stimulation (DBS) lead can provide useful feedback for titrating DBS therapy. However, conventional DBS leads with four cylindrical macroelectrodes likely undersample the spatial distribution of sinks and sources in a given brain region. In this study, we investigated the spectral power and spatial feature sizes of LFP activity in non-human primate subthalamic nucleus and globus pallidus using chronically implanted 32-channel directional DBS arrays.
 Approach: Subthalamic nucleus and globus pallidus LFP signals were recorded from directional DBS arrays in the resting state and during a reach-and-retrieval task in two non-human primates in naïve and parkinsonian conditions...
April 13, 2018: Journal of Neural Engineering
Yi Tan, Tommy Tsan-Yuk Lam, Lea A Heberlein-Larson, Sandra C Smole, Albert J Auguste, Scott Hennigan, Rebecca A Halpin, Nadia Fedorova, Vinita Puri, Timothy B Stockwell, Meghan H Shilts, Theodore Andreadis, Philip M Armstrong, Robert B Tesh, Scott C Weaver, Thomas R Unnasch, Alexander T Ciota, Laura D Kramer, Suman R Das
Eastern equine encephalitis virus (EEEV) has a high case-fatality rate in horses and humans, and Florida has been hypothesized to be the source of EEEV epidemics for the northeastern U.S. To test this hypothesis, we sequenced complete genomes of 433 EEEV strains collected within the U.S. from 1934 to 2014. Phylogenetic analysis suggested EEEV evolves relatively slowly and that transmission is enzootic in Florida, characterized by higher genetic diversity and long-term local persistence. In contrast, EEEV in New York and Massachusetts were characterized by lower genetic diversity, multiple introductions, and shorter local persistence...
April 4, 2018: Journal of Virology
Courtney Sobieski, Natasha Warikoo, Hong-Jin Shu, Steven Mennerick
Neurons require a nearly constant supply of ATP. Glucose is the predominant source of brain ATP, but the direct effects of prolonged glucose deprivation on neuronal viability and function remain unclear. In sparse rat hippocampal microcultures, neurons were surprisingly resilient to 16 h glucose removal in the absence of secondary excitotoxicity. Neuronal survival and synaptic transmission were unaffected by prolonged removal of exogenous glucose. Inhibition of lactate transport decreased microculture neuronal survival during concurrent glucose deprivation, suggesting that endogenously released lactate is important for tolerance to glucose deprivation...
2018: PloS One
Ileana Quiñones, Nicola Molinaro, Simona Mancini, Juan Andrés Hernández-Cabrera, Horacio Barber, Manuel Carreiras
The current fMRI study was designed to investigate whether the processing of different gender-related cues embedded in nouns affects the computation of agreement dependencies and, if so, where this possible interaction is mapped in the brain. We used the Spanish gender agreement system, which makes it possible to manipulate two different factors: the agreement between different sentence constituents (i.e., by contrasting congruent versus incongruent determiner-noun pairs) and the formal (i.e., orthographical/morphological) and/or lexical information embedded in the noun -i...
March 29, 2018: NeuroImage
Gavin M Bidelman
Frequency-following responses (FFRs) are neurophonic potentials that provide a window into the encoding of complex sounds (e.g., speech/music), auditory disorders, and neuroplasticity. While the neural origins of the FFR remain debated, renewed controversy has reemerged after demonstration that FFRs recorded via magnetoencephalography (MEG) are dominated by cortical rather than brainstem structures as previously assumed. Here, we recorded high-density (64 ch) FFRs via EEG and applied state-of-the art source imaging techniques to multichannel data (discrete dipole modeling, distributed imaging, independent component analysis, computational simulations)...
March 28, 2018: NeuroImage
Pieter van Mierlo, Gregor Strobbe, Vincent Keereman, Gwénael Birot, Stefanie Gadeyne, Markus Gschwind, Evelien Carrette, Alfred Meurs, Dirk Van Roost, Kristl Vonck, Margitta Seeck, Serge Vulliémoz, Paul Boon
Objective: We investigated the performance of automatic spike detection and subsequent electroencephalogram (EEG) source imaging to localize the epileptogenic zone (EZ) from long-term EEG recorded during video-EEG monitoring. Methods: In 32 patients, spikes were automatically detected in the EEG and clustered according to their morphology. The two spike clusters with most single events in each patient were averaged and localized in the brain at the half-rising time and peak of the spike using EEG source imaging...
September 2017: Epilepsia Open
Eslam Taha, Fathi Djouider, Essam Banoqitah
The objective of this work is to study the dosimetric performances of bismuth oxide nanoparticles implanted in tumors in cancer radiotherapy. GEANT4 based Monte Carlo numerical simulations were performed to assess dose enhancement distributions in and around a 1 × 1 × 1 cm3 tumor implanted with different concentrations of bismuth oxide and irradiated with low energies125 I,131 Cs, and103 Pd radioactive sources. Dose contributions were considered from photoelectrons, Auger electrons, and characteristic X-rays...
March 26, 2018: Australasian Physical & Engineering Sciences in Medicine
Johannes Vorwerk, Robert Oostenveld, Maria Carla Piastra, Lilla Magyari, Carsten H Wolters
BACKGROUND: Accurately solving the electroencephalography (EEG) forward problem is crucial for precise EEG source analysis. Previous studies have shown that the use of multicompartment head models in combination with the finite element method (FEM) can yield high accuracies both numerically and with regard to the geometrical approximation of the human head. However, the workload for the generation of multicompartment head models has often been too high and the use of publicly available FEM implementations too complicated for a wider application of FEM in research studies...
March 27, 2018: Biomedical Engineering Online
Vladimir Ljubojevic, Paul Luu, Patrick Robert Gill, Lee-Anne Beckett, Kaori Takehara-Nishiuchi, Eve De Rosa
A critical function of attention is to support a state of readiness to enhance stimulus detection, independent of stimulus modality. The nucleus basalis magnocellularis (NBM) is the major source of the neurochemical acetylcholine (ACh) for frontoparietal cortical networks thought to support attention. We examined a potential supramodal role of ACh in a frontoparietal cortical attentional network supporting target detection. We recorded local field potentials (LFP) in the prelimbic frontal (PFC) and the posterior parietal (PPC) cortices to assess whether ACh contributed to a state of readiness to alert rats to an impending presentation of visual or olfactory targets in one of five locations...
March 23, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Quanying Liu, Marco Ganzetti, Nicole Wenderoth, Dante Mantini
Resting state networks (RSNs) in the human brain were recently detected using high-density electroencephalography (hdEEG). This was done by using an advanced analysis workflow to estimate neural signals in the cortex and to assess functional connectivity (FC) between distant cortical regions. FC analyses were conducted either using temporal (tICA) or spatial independent component analysis (sICA). Notably, EEG-RSNs obtained with sICA were very similar to RSNs retrieved with sICA from functional magnetic resonance imaging data...
2018: Frontiers in Neuroinformatics
Satoshi Kuroki, Takamasa Yoshida, Hidekazu Tsutsui, Mizuho Iwama, Reiko Ando, Takayuki Michikawa, Atsushi Miyawaki, Toshio Ohshima, Shigeyoshi Itohara
Multisensory integration (MSI) is a fundamental emergent property of the mammalian brain. During MSI, perceptual information encoded in patterned activity is processed in multimodal association cortex. The systems-level neuronal dynamics that coordinate MSI, however, are unknown. Here, we demonstrate intrinsic hub-like network activity in the association cortex that regulates MSI. We engineered calcium reporter mouse lines based on the fluorescence resonance energy transfer sensor yellow cameleon (YC2.60) expressed in excitatory or inhibitory neurons...
March 13, 2018: Cell Reports
Eline R Kupers, Helena X Wang, Kaoru Amano, Kendrick N Kay, David J Heeger, Jonathan Winawer
Currently, non-invasive methods for studying the human brain do not routinely and reliably measure spike-rate-dependent signals, independent of responses such as hemodynamic coupling (fMRI) and subthreshold neuronal synchrony (oscillations and event-related potentials). In contrast, invasive methods-microelectrode recordings and electrocorticography (ECoG)-have recently measured broadband power elevation in field potentials (~50-200 Hz) as a proxy for locally averaged spike rates. Here, we sought to detect and quantify stimulus-related broadband responses using magnetoencephalography (MEG)...
2018: PloS One
Kensuke Sekihara, Yoshiaki Adachi, Hiroshi K Kubota, Chang Cai, Srikantan S Nagarajan
Magnetoencephalography (MEG)
 has a well-recognized weakness at detecting deeper brain activities. This paper proposes a novel algorithm for selective detection of deep sources by suppressing interference signals from superficial sources in magnetoencephalographic (MEG) measurements. 
 Approach: The proposed algorithm combines the beamspace preprocessing method with the dual signal space projection (DSSP) interference suppression method. A prerequisite of the proposed algorithm is prior knowledge of the location of the deep sources...
March 12, 2018: Journal of Neural Engineering
Shruti G Vij, Jason S Nomi, Dina R Dajani, Lucina Q Uddin
Development and aging are associated with functional changes in the brain across the lifespan. These changes manifest in a variety of spatial and temporal features of resting state functional MRI (rs-fMRI) but have seldom been explored exhaustively. We present a comprehensive study assessing age-related changes in spatial and temporal features of blind-source separated components identified by independent vector analysis (IVA) in a cross-sectional lifespan sample (ages 6-85 years). We show that while large-scale network configurations remain consistent throughout the lifespan, changes persist in both local and global organization of these networks...
March 6, 2018: NeuroImage
Jesper D Nielsen, Kristoffer H Madsen, Oula Puonti, Hartwig R Siebner, Christian Bauer, Camilla Gøbel Madsen, Guilherme B Saturnino, Axel Thielscher
Anatomically realistic volume conductor models of the human head are important for accurate forward modeling of the electric field during transcranial brain stimulation (TBS), electro- (EEG) and magnetoencephalography (MEG). In particular, the skull compartment exerts a strong influence on the field distribution due to its low conductivity, suggesting the need to represent its geometry accurately. However, automatic skull reconstruction from structural magnetic resonance (MR) images is difficult, as compact bone has a very low signal in magnetic resonance imaging (MRI)...
March 5, 2018: NeuroImage
M Palau-Baduell, B Salvado-Salvado, M A Idiazabal-Alecha, A Fernandez-Teruel, T Ortiz
INTRODUCTION: The perisylvian areas, located around the Sylvian fissure, are constituted by frontal, temporal and parietal brain regions. These are connected forming specialized neural networks and play a primary role in the development of linguistic skills and social cognition. These areas are a possible neuronal substrate of cognitive and behavioral impairments in patients with autism spectrum disorders (ASD). AIM: To locate and quantify epileptiform activity sources through magnetoencephalography in frontal perisylvian areas in children with idiopathic ASD...
March 1, 2018: Revista de Neurologia
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