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Magnetoencephalography

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https://www.readbyqxmd.com/read/28635497/desynchronisation-of-auditory-steady-state-responses-related-to-changes-in-interaural-phase-differences-an-objective-measure-of-binaural-hearing
#1
Charlotte Vercammen, Astrid van Wieringen, Jan Wouters, Tom Francart
OBJECTIVE: Binaural processing can be measured objectively as a desynchronisation of phase-locked neural activity to changes in interaural phase differences (IPDs). This was reported in a magnetoencephalography study for 40 Hz amplitude modulated tones. The goal of this study was to measure this desynchronisation using electroencephalography and explore the outcomes for different modulation frequencies. DESIGN: Auditory steady-state responses (ASSRs) were recorded to pure tones, amplitude modulated at 20, 40 or 80 Hz...
February 14, 2017: International Journal of Audiology
https://www.readbyqxmd.com/read/28626250/association-between-changes-in-visual-evoked-magnetic-fields-and-non-motor-features-in-parkinson-s-disease
#2
Yoshiro Fujisawa, Tomomi Minato, Jun-Ichi Uemura, Minoru Hoshiyama, Hirohisa Watanabe, Masaaki Hirayama
Visual dysfunction can be caused by several abnormalities, including dysfunctions in the visual cortex and retina. Our aim was to investigate changes in visual evoked brain responses in the primary visual cortex associated with Parkinson's disease (PD). Sixteen healthy control subjects and ten patients with PD participated in this study. We assessed the visual evoked magnetic field (VEF) using magnetoencephalography (MEG). Checkerboard pattern reversal (CPR) and monotonous grating pattern (MGP) stimulations were used...
February 2017: Nagoya Journal of Medical Science
https://www.readbyqxmd.com/read/28626018/dissecting-the-function-of-hippocampal-oscillations-in-a-human-anxiety-model
#3
Saurabh Khemka, Gareth Barnes, Raymond J Dolan, Dominik R Bach
Neural oscillations in hippocampus and medial prefrontal cortex (mPFC) are a hallmark of rodent anxiety models that build on conflict between approach and avoidance. Yet, the function of these oscillations, and their expression in humans, remain elusive. Here, we used magnetoencephalography (MEG) to investigate neural oscillations in a task that simulated approach-avoidance conflict, wherein 23 male and female human participants collected monetary tokens under a threat of virtual predation. Probability of threat was learned beforehand by direct experience...
June 16, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28623753/precuneal-epilepsy-clinical-features-and-surgical-outcome
#4
Adil Harroud, Olivier Boucher, Thi Phuoc Yen Tran, Louis Harris, Jeffery Hall, François Dubeau, Ismail Mohamed, Alain Bouthillier, Dang Khoa Nguyen
OBJECTIVE: The precuneus is a complex and highly connected structure located in the medial portion of the superior parietal lobule. The clinical presentation of precuneal epilepsy is poorly characterized, mostly because these patients have seldom been distinguished from those with other types of parietal lobe epilepsy. The present study aims to improve the understanding of precuneal epilepsy by detailing its clinical features and surgical outcomes. METHODS: Six previously unreported cases of drug-resistant precuneal epilepsy investigated between 2002 and 2014 were retrospectively studied...
June 14, 2017: Epilepsy & Behavior: E&B
https://www.readbyqxmd.com/read/28623727/current-clinical-magnetoencephalography-practice-across-europe-are-we-closer-to-use-meg-as-an-established-clinical-tool
#5
Xavier De Tiège, Daniel Lundqvist, Sándor Beniczky, Stefano Seri, Ritva Paetau
PURPOSE: This comprehensive survey aims at characterizing the current clinical use of magnetoencephalography (MEG) across European MEG centres. METHODS: Forty-four MEG centres across Europe were contacted in May 2015 via personalized e-mail to contribute to survey. The web-based survey was available on-line for 1 month and the MEG centres that did not respond were further contacted to maximize participation. RESULTS: Among the 57% of responders, 12 centres from 10 different countries reported to use MEG for clinical applications...
June 8, 2017: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/28622627/changes-in-nonhuman-primate-brain-function-following-chronic-alcohol-consumption-in-previously-na%C3%A3-ve-animals
#6
Jared A Rowland, Jennifer R Stapleton-Kotloski, Greg E Alberto, April T Davenport, Robert J Kotloski, David P Friedman, Dwayne W Godwin, James B Daunais
INTRODUCTION: Chronic alcohol abuse is associated with neurophysiological changes in brain activity; however, these changes are not well localized in humans. Non-human primate models of alcohol abuse enable control over many potential confounding variables associated with human studies. The present study utilized high-resolution magnetoencephalography (MEG) to quantify the effects of chronic EtOH self-administration on resting state (RS) brain function in vervet monkeys. METHODS: Adolescent male vervet monkeys were trained to self-administer ethanol (n=7) or an isocaloric malto-dextrin solution (n=3)...
May 30, 2017: Drug and Alcohol Dependence
https://www.readbyqxmd.com/read/28622527/alzheimer-s-disease-the-state-of-the-art-in-resting-state-magnetoencephalography
#7
REVIEW
M M A Engels, W M van der Flier, C J Stam, A Hillebrand, Ph Scheltens, E C W van Straaten
Alzheimer's disease (AD) is accompanied by functional brain changes that can be detected in imaging studies, including electromagnetic activity recorded with magnetoencephalography (MEG). Here, we systematically review the studies that have examined resting-state MEG changes in AD and identify areas that lack scientific or clinical progress. Three levels of MEG analysis will be covered: (i) single-channel signal analysis, (ii) pairwise analyses over time series, which includes the study of interdependencies between two time series and (iii) global network analyses...
May 21, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28622421/how-to-record-high-frequency-oscillations-in-epilepsy-a-practical-guideline
#8
REVIEW
Maeike Zijlmans, Gregory A Worrell, Matthias Dümpelmann, Thomas Stieglitz, Andrei Barborica, Marcel Heers, Akio Ikeda, Naotaka Usui, Michel Le Van Quyen
OBJECTIVE: Technology for localizing epileptogenic brain regions plays a central role in surgical planning. Recent improvements in acquisition and electrode technology have revealed that high-frequency oscillations (HFOs) within the 80-500 Hz frequency range provide the neurophysiologist with new information about the extent of the epileptogenic tissue in addition to ictal and interictal lower frequency events. Nevertheless, two decades after their discovery there remain questions about HFOs as biomarkers of epileptogenic brain and there use in clinical practice...
June 16, 2017: Epilepsia
https://www.readbyqxmd.com/read/28621621/indications-technique-and-safety-profile-of-insular-stereoelectroencephalography-electrode-implantation-in-medically-intractable-epilepsy
#9
Soha Alomar, Jeffrey P Mullin, Saksith Smithason, Jorge Gonzalez-Martinez
OBJECTIVE Insular epilepsy is relatively rare; however, exploring the insular cortex when preoperative workup raises the suspicion of insular epilepsy is of paramount importance for accurate localization of the epileptogenic zone and achievement of seizure freedom. The authors review their clinical experience with stereoelectroencephalography (SEEG) electrode implantation in patients with medically intractable epilepsy and suspected insular involvement. METHODS A total of 198 consecutive cases in which patients underwent SEEG implantation with a total of 1556 electrodes between June 2009 and April 2013 were reviewed...
June 16, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28619655/comparison-of-the-spatial-resolution-of-source-imaging-techniques-in-high-density-eeg-and-meg
#10
T Hedrich, G Pellegrino, E Kobayashi, J M Lina, C Grova
BACKGROUND: The present study aims at evaluating and comparing electrical and magnetic distributed source imaging methods applied to high-density Electroencephalography (hdEEG) and Magnetoencephalography (MEG) data. We used resolution matrices to characterize spatial resolution properties of Minimum Norm Estimate (MNE), dynamic Statistical Parametric Mapping (dSPM), standardized Low-Resolution Electromagnetic Tomography (sLORETA) and coherent Maximum Entropy on the Mean (cMEM, an entropy-based technique)...
June 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/28617862/evaluating-age-related-change-in-lip-somatosensation-using-somatosensory-evoked-magnetic-fields
#11
Hiroki Hihara, Hiroyasu Kanetaka, Akitake Kanno, Satoko Koeda, Nobukazu Nakasato, Ryuta Kawashima, Keiichi Sasaki
Somatosensory evoked fields (SEFs) to electrical stimulation on the right and left sides of the lower lip were measured using magnetoencephalography and compared in the bilateral hemispheres of 31 healthy normal young and 29 healthy normal elderly subjects to evaluate age-related change in lip somatosensation. The initial peak of the response around 13 ms, designated as N13m, and the second peak of the response, designated as P21m, were investigated. The N13m response, which was detected in 22 of 62 hemispheres in young adults and 37 of 58 hemispheres in elderly adults, showed significantly prolonged latency and increased equivalent current dipole (ECD) moment in the elderly adults...
2017: PloS One
https://www.readbyqxmd.com/read/28615963/frequency-dependent-changes-in-sensorimotor-and-pain-affective-systems-induced-by-empathy-for-pain
#12
Yoshimasa Motoyama, Katsuya Ogata, Sumio Hoka, Shozo Tobimatsu
BACKGROUND: Empathy for pain helps us to understand the pain of others indirectly. To better comprehend the processing of empathic pain, we report the frequency-dependent modulation of cortical oscillations induced by watching movies depicting pain using high-density electroencephalography (EEG), magnetoencephalography (MEG), and motor evoked potentials (MEP). METHODS: Event-related desynchronization of EEG and MEG was assessed while participants viewed videos of painful (needle) or neutral (cotton swab) situations...
2017: Journal of Pain Research
https://www.readbyqxmd.com/read/28612661/is-there-an-association-between-mismatch-negativity-and-cortical-thickness-in-schizophrenia-patients
#13
Jiyoon J Seol, Minah Kim, Kwang Hyuk Lee, Ji-Won Hur, Kang Ik K Cho, Tae Young Lee, Chun Kee Chung, Jun Soo Kwon
INTRODUCTION: Mismatch negativity (MMN) is thought to reflect preattentive, automatic auditory processing. Reduced MMN amplitude is among the most robust findings in schizophrenia research. MMN generators have been shown to be located in the temporal and frontal cortices, which are key areas in the pathophysiology of schizophrenia. This study investigated whether frontotemporal cortical thickness was associated with reduced MMN current source density (CSD) strength in patients with schizophrenia...
June 1, 2017: Clinical EEG and Neuroscience: Official Journal of the EEG and Clinical Neuroscience Society (ENCS)
https://www.readbyqxmd.com/read/28611613/simultaneous-processing-of-noun-cue-and-to-be-produced-verb-in-verb-generation-task-electromagnetic-evidence
#14
Anna V Butorina, Anna A Pavlova, Anastasia Y Nikolaeva, Andrey O Prokofyev, Denis P Bondarev, Tatiana A Stroganova
A long-standing but implicit assumption is that words strongly associated with a presented cue are automatically activated in the memory through rapid spread of activation within brain semantic networks. The current study was aimed to provide direct evidence of such rapid access to words' semantic representations and to investigate its neural sources using magnetoencephalography (MEG) and distributed source localization technique. Thirty-three neurotypical subjects underwent the MEG recording during verb generation task, which was to produce verbs related to the presented noun cues...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28607165/the-cumulative-effects-of-predictability-on-synaptic-gain-in-the-auditory-processing-stream
#15
Ryszard Auksztulewicz, Nicolas Barascud, Gerald Cooray, Anna Christina Nobre, Maria Chait, Karl Friston
Stimulus predictability can lead to substantial modulations of brain activity, such as shifts in sustained magnetic field amplitude, measured with magnetoencephalography. Here, we provide a mechanistic explanation of these effects using MEG data acquired from healthy human volunteers (N=13, 7 female). In a source-level analysis of induced responses, we established the effects of orthogonal predictability manipulations of rapid tone-pip sequences (namely, sequence regularity and alphabet size) along the auditory processing stream...
June 8, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28591842/children-with-cerebral-palsy-hyper-gate-somatosensory-stimulations-of-the-foot
#16
Max J Kurz, Alex I Wiesman, Nathan M Coolidge, Tony W Wilson
We currently have a substantial knowledge gap in our understanding of the neurophysiological underpinnings of the sensory perception deficits often reported in the clinic for children with cerebral palsy (CP). In this investigation, we have begun to address this knowledge gap by using magnetoencephalography (MEG) brain imaging to evaluate the sensory gating of neural oscillations in the somatosensory cortices. A cohort of children with CP (Gross Motor Function Classification System II-III) and typically developing children underwent paired-pulse electrical stimulation of the tibial nerve during MEG...
June 7, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28580720/learned-control-of-inter-hemispheric-connectivity-effects-on-bimanual-motor-performance
#17
Diljit Singh Kajal, Christoph Braun, Jürgen Mellinger, Matthew D Sacchet, Sergio Ruiz, Eberhard Fetz, Niels Birbaumer, Ranganatha Sitaram
Bimanual movements involve the interactions between both primary motor cortices. These interactions are assumed to involve phase-locked oscillatory brain activity referred to as inter-hemispheric functional coupling. So far, inter-hemispheric functional coupling has been investigated as a function of motor performance. These studies report mostly a negative correlation between the performance in motor tasks and the strength of functional coupling. However, correlation might not reflect a causal relationship...
June 5, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28580622/heightened-amygdala-responsiveness-in-s-carriers-of-5-httlpr-genetic-polymorphism-reflects-enhanced-cortical-rather-than-subcortical-inputs-an-meg-study
#18
Qian Luo, Tom Holroyd, Derek Mitchell, Henry Yu, Xi Cheng, Colin Hodgkinson, Gang Chen, Daniel McCaffrey, David Goldman, R James Blair
Short allele carriers (S-carriers) of the serotonin transporter gene (5-HTTLPR) show an elevated amygdala response to emotional stimuli relative to long allele carriers (LL-homozygous). However, whether this reflects increased responsiveness of the amygdala generally or interactions between the amygdala and the specific input systems remains unknown. It is argued that the amygdala receives input via a quick subcortical and a slower cortical pathway. If the elevated amygdala response in S-carriers reflects generally increased amygdala responding, then group differences in amygdala should be seen across the amygdala response time course...
June 5, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28577876/a-preliminary-study-on-the-neural-oscillatory-characteristics-of-motor-preparation-prior-to-dysfluent-and-fluent-utterances-in-adults-who-stutter
#19
Anna Mersov, Douglas Cheyne, Cecilia Jobst, Luc De Nil
PURPOSE: Recent literature on speech production in adults who stutter (AWS) has begun to investigate the neural mechanisms characterizing speech-motor preparation prior to speech onset. Compelling evidence has suggested that stuttering is associated with atypical processing within cortical and sub-cortical motor networks, particularly in the beta frequency range, that is effective before speech production even begins. Due to low stuttering frequency in experimental settings, however, the literature has so far predominantly reported on fluent speech production in AWS...
May 17, 2017: Journal of Fluency Disorders
https://www.readbyqxmd.com/read/28576731/quantify-neuromagnetic-network-changes-from-pre-ictal-to-ictal-activities-in-absence-seizures
#20
Caiyun Wu, Jing Xiang, Jintao Sun, Shuyang Huang, Lu Tang, Ailiang Miao, Yuchen Zhou, Qiqi Chen, Zheng Hu, Xiaoshan Wang
OBJECTIVE: The cortico-thalamo-cortical network plays a key role in childhood absence epilepsy (CAE). However, the exact interaction between the cortex and the thalamus remains incompletely understood. This study aimed to investigate the dynamic changes of frequency-dependent neural networks during the initialization of absence seizures. METHODS: Magnetoencephalography data from 14 patients with CAE were recorded during and between seizures at a sampling rate of 6000Hz and analyzed in seven frequency bands...
May 31, 2017: Neuroscience
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