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Magnetoencephalography

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https://www.readbyqxmd.com/read/28325030/application-of-meg-coherence-in-lateralization-of-mtle
#1
Mohammad R Nazem-Zadeh, Susan M Bowyer, John E Moran, Esmaeil Davoodi-Bojd, Andrew Zillgitt, Hassan Bagher-Ebadian, Fariborz Mahmoudi, Kost V Elisevich, Hamid Soltanian-Zadeh
Magnetoencephalography (MEG) is a noninvasive imaging method for localization of focal epileptiform activity in patients with epilepsy. This study investigates the cerebral functional abnormalities quantified by MEG coherence laterality in mesial temporal lobe epilepsy (mTLE). Resting state MEG data was analyzed using MEG coherence source imaging (MEG-CSI) method to determine the coherence in 54 anatomical sites in 12 adult mTLE patients and 12 age- and gender-matched controls. MEG coherence laterality, after Bonferroni adjustment, showed significant differences for right versus left mTLE in insular cortex and both lateral orbitofrontal and superior temporal gyri (p<;0...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28319873/magnetoencephalography-with-temporal-spread-imaging-to-visualize-propagation-of-epileptic-activity
#2
Sumiya Shibata, Masao Matsuhashi, Takeharu Kunieda, Yukihiro Yamao, Rika Inano, Takayuki Kikuchi, Hisaji Imamura, Shigetoshi Takaya, Riki Matsumoto, Akio Ikeda, Ryosuke Takahashi, Tatsuya Mima, Hidenao Fukuyama, Nobuhiro Mikuni, Susumu Miyamoto
OBJECTIVE: We describe temporal spread imaging (TSI) that can identify the spatiotemporal pattern of epileptic activity using Magnetoencephalography (MEG). METHODS: A three-dimensional grid of voxels covering the brain is created. The array-gain minimum-variance spatial filter is applied to an interictal spike to estimate the magnitude of the source and the time (Ta) when the magnitude exceeds a predefined threshold at each voxel. This calculation is performed through all spikes...
January 30, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28316771/disconnection-from-others-in-autism-is-more-than-just-a-feeling-whole-brain-neural-synchrony-in-adults-during-implicit-processing-of-emotional-faces
#3
Rocco Mennella, Rachel C Leung, Margot J Taylor, Benjamin T Dunkley
BACKGROUND: Socio-emotional difficulties in autism spectrum disorder (ASD) are thought to reflect impaired functional connectivity within the "social brain". Nonetheless, a whole-brain characterization of the fast responses in functional connectivity during implicit processing of emotional faces in adults with ASD is lacking. METHODS: The present study used magnetoencephalography to investigate early responses in functional connectivity, as measured by interregional phase synchronization, during implicit processing of angry, neutral and happy faces...
2017: Molecular Autism
https://www.readbyqxmd.com/read/28316456/functional-connectivity-of-the-pedunculopontine-nucleus-and-surrounding-region-in-parkinson-s-disease
#4
Ashwani Jha, Vladimir Litvak, Samu Taulu, Wesley Thevathasan, Jonathan A Hyam, Tom Foltynie, Patricia Limousin, Marko Bogdanovic, Ludvic Zrinzo, Alexander L Green, Tipu Z Aziz, Karl Friston, Peter Brown
Deep brain stimulation of the pedunculopontine nucleus and surrounding region (PPNR) is a novel treatment strategy for gait freezing in Parkinson's disease (PD). However, clinical results have been variable, in part because of the paucity of functional information that might help guide selection of the optimal surgical target. In this study, we use simultaneous magnetoencephalography and local field recordings from the PPNR in seven PD patients, to characterize functional connectivity with distant brain areas at rest...
January 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28290271/diminished-modulation-of-preparatory-sensorimotor-mu-rhythm-predicts-attention-deficit-hyperactivity-disorder-severity
#5
N Ter Huurne, D Lozano-Soldevilla, M Onnink, C Kan, J Buitelaar, O Jensen
BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is characterized by problems in regulating attention and in suppressing disruptive motor activity, i.e. hyperactivity and impulsivity. We recently found evidence that aberrant distribution of posterior α band oscillations (8-12 Hz) is associated with attentional problems in ADHD. The sensorimotor cortex also produces strong 8-12 Hz band oscillations, namely the μ rhythm, and is thought to have a similar inhibitory function...
March 14, 2017: Psychological Medicine
https://www.readbyqxmd.com/read/28286918/altered-effective-connectivity-network-in-childhood-absence-epilepsy-a-multi-frequency-meg-study
#6
Caiyun Wu, Jing Xiang, Wenwen Jiang, Shuyang Huang, Yuan Gao, Lu Tang, Yuchen Zhou, Di Wu, Qiqi Chen, Zheng Hu, Xiaoshan Wang
Using multi-frequency magnetoencephalography (MEG) data, we investigated whether the effective connectivity (EC) network of patients with childhood absence epilepsy (CAE) is altered during the inter-ictal period in comparison with healthy controls. MEG data from 13 untreated CAE patients and 10 healthy controls were recorded. Correlation analysis and Granger causality analysis were used to construct an EC network at the source level in eight frequency bands. Alterations in the spatial pattern and topology of the network in CAE were investigated by comparing the patients with the controls...
March 12, 2017: Brain Topography
https://www.readbyqxmd.com/read/28283563/a-rapid-subcortical-amygdala-route-for-faces-irrespective-of-spatial-frequency-and-emotion
#7
Jessica McFadyen, Martial Mermillod, Jason B Mattingley, Veronika Halász, Marta I Garrido
There is significant controversy over the existence and function of a direct subcortical visual pathway to the amygdala. It is thought that this pathway rapidly transmits low spatial frequency information to the amygdala independently of the cortex and yet the directionality of this function has never been determined. We used magnetoencephalography to measure neural activity while human participants discriminated the gender of neutral and fearful faces filtered for low or high spatial frequencies. We applied dynamic causal modelling to demonstrate that the most likely underlying neural network consisted of a pulvinar-amygdala connection that was uninfluenced by spatial frequency or emotion, and a cortical-amygdala connection that conveyed high spatial frequencies...
March 10, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28282963/multimodal-brain-imaging-with-magnetoencephalography-a-method-for-measuring-blood-pressure-and-cardiorespiratory-oscillations
#8
Teemu Myllylä, Norman Zacharias, Vesa Korhonen, Aleksandra Zienkiewicz, Hermann Hinrichs, Vesa Kiviniemi, Martin Walter
Studies with magnetoencephalography (MEG) are still quite rarely combined simultaneously with methods that can provide a metabolic dimension to MEG investigations. In addition, continuous blood pressure measurements which comply with MEG compatibility requirements are lacking. For instance, by combining methods reflecting neurovascular status one could obtain more information on low frequency fluctuations that have recently gained increasing interest as a mediator of functional connectivity within brain networks...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28281494/role-of-magnetoencephalography-and-stereo-electroencephalography-in-the-presurgical-evaluation-in-patients-with-drug-resistant-epilepsy
#9
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/28279670/normal-voice-processing-after-posterior-superior-temporal-sulcus-lesion
#10
Guo Jiahui, Lúcia Garrido, Ran R Liu, Tirta Susilo, Jason J S Barton, Bradley Duchaine
The right posterior superior temporal sulcus (pSTS) shows a strong response to voices, but the cognitive processes generating this response are unclear. One possibility is that this activity reflects basic voice processing. However, several fMRI and magnetoencephalography findings suggest instead that pSTS serves as an integrative hub that combines voice and face information. Here we investigate whether right pSTS contributes to basic voice processing by testing Faith, a patient whose right pSTS was resected, with eight behavioral tasks assessing voice identity perception and recognition, voice sex perception, and voice expression perception...
March 6, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28271041/the-cortical-signature-of-symptom-laterality-in-parkinson-s-disease
#11
Elizabeth Heinrichs-Graham, Pamela M Santamaria, Howard E Gendelman, Tony W Wilson
Patients with Parkinson's disease (PD) often present with unilateral motor symptoms that eventually spread to the other side. This symptom lateralization is diagnostically important, as it serves to distinguish PD from other motor disorders with overlapping symptom profiles. Further, recent studies have shown that the side of symptom onset is important for prognosis, as there are differences in the rate of disease progression and the incidence of secondary symptoms between right- and left-dominant (RD, LD) patients...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28270567/whole-brain-neural-dynamics-of-probabilistic-reward-prediction
#12
Dominik R Bach, Mkael Symmonds, Gareth Barnes, Raymond J Dolan
Predicting future reward is paramount to performing an optimal action. While a number of brain areas are known to encode such predictions, a detailed account of how the associated representations evolve over time is lacking. Here, we address this question using human magnetoencephalography (MEG) and multivariate analyses of instantaneous activity in reconstructed sources. We over-trained participants on a simple instrumental reward learning task where geometric cues predicted a distribution of possible rewards, from which a sample was revealed 2000 ms later...
March 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28269286/alpha-band-rhythm-suppression-during-memory-recall-reflecting-memory-performance
#13
Koichi Yokosawa, Keisuke Kimura, Ryota Chitose, Takuya Momiki, Shinya Kuriki
Alpha-band rhythm is thought to be involved in memory processes, similarly to other spontaneous brain rhythms. Ten right-handed healthy volunteers participated in our proposed sequential short-term memory task that provides a serial position effect in accuracy rate. We recorded alpha-band rhythms by magnetoencephalography during performance of the task and observed that the amplitude of the rhythm was suppressed dramatically in the memory recall period. The suppressed region was estimated to be in the occipital lobe, suggesting that alpha-band rhythm is suppressed by activation of the occipital attentional network...
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
#14
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
#15
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/28268430/analysis-of-magnetoencephalography-signals-from-alzheimer-s-disease-patients-using-granger-causality
#16
Celia Juan-Cruz, Carlos Gomez, Jesus Poza, Alberto Fernandez, Roberto Hornero
The aim of this study was to analyze resting-state magnetoencephalography (MEG) activity in Alzheimer's disease (AD) by means of Granger Causality (GC), an effective connectivity measure that provides an estimation of the information flow between brain regions. For this task, five minutes of MEG recordings were acquired with a 148-channel whole-head magnetometer from 36 AD patients and 26 healthy controls. Abnormalities in AD connectivity were found in the five typical frequency bands: delta (δ, 1-4 Hz), theta (θ, 4-8 Hz), alpha (α, 8-13 Hz), beta (β, 13-30 Hz), and gamma (γ, 30-65 Hz)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268122/the-right-hemisphere-is-highlighted-in-connected-natural-speech-production-and-perception
#17
Anna Maria Alexandrou, Timo Saarinen, Sasu Mäkelä, Jan Kujala, Riitta Salmelin
Current understanding of the cortical mechanisms of speech perception and production stems mostly from studies that focus on single words or sentences. However, it has been suggested that processing of real-life connected speech may rely on additional cortical mechanisms. In the present study, we examined the neural substrates of natural speech production and perception with magnetoencephalography by modulating three central features related to speech: amount of linguistic content, speaking rate and social relevance...
March 4, 2017: NeuroImage
https://www.readbyqxmd.com/read/28259857/auditory-training-changes-temporal-lobe-connectivity-in-wernicke-s-aphasia-a-randomised-trial
#18
Zoe Vj Woodhead, Jennifer Crinion, Sundeep Teki, Will Penny, Cathy J Price, Alexander P Leff
INTRODUCTION: Aphasia is one of the most disabling sequelae after stroke, occurring in 25%-40% of stroke survivors. However, there remains a lack of good evidence for the efficacy or mechanisms of speech comprehension rehabilitation. TRIAL DESIGN: This within-subjects trial tested two concurrent interventions in 20 patients with chronic aphasia with speech comprehension impairment following left hemisphere stroke: (1) phonological training using 'Earobics' software and (2) a pharmacological intervention using donepezil, an acetylcholinesterase inhibitor...
March 4, 2017: Journal of Neurology, Neurosurgery, and Psychiatry
https://www.readbyqxmd.com/read/28258363/theta-rhythm-makes-the-world-go-round-dissociative-effects-of-tms-theta-versus-alpha-entrainment-of-right-ptpj-on-embodied-perspective-transformations
#19
Gerard Gooding-Williams, Hongfang Wang, Klaus Kessler
Being able to imagine another person's experience and perspective of the world is a crucial human ability and recent reports suggest that humans "embody" another's viewpoint by mentally rotating their own body representation into the other's orientation. Our recent Magnetoencephalography (MEG) data further confirmed this notion of embodied perspective transformations and pinpointed the right posterior temporo-parietal junction (pTPJ) as the crucial hub in a distributed network oscillating at theta frequency (3-7 Hz)...
March 3, 2017: Brain Topography
https://www.readbyqxmd.com/read/28253445/preparatory-attention-in-visual-cortex
#20
REVIEW
Elisa Battistoni, Timo Stein, Marius V Peelen
Top-down attention is the mechanism that allows us to selectively process goal-relevant aspects of a scene while ignoring irrelevant aspects. A large body of research has characterized the effects of attention on neural activity evoked by a visual stimulus. However, attention also includes a preparatory phase before stimulus onset in which the attended dimension is internally represented. Here, we review neurophysiological, functional magnetic resonance imaging, magnetoencephalography, electroencephalography, and transcranial magnetic stimulation (TMS) studies investigating the neural basis of preparatory attention, both when attention is directed to a location in space and when it is directed to nonspatial stimulus attributes (content-based attention) ranging from low-level features to object categories...
March 2, 2017: Annals of the New York Academy of Sciences
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