Temporal Unfolding of Racial Ingroup Bias in Neural Responses to Perceived Dynamic Pain in Others / 神经科学通报·英文版

In this study, we investigated how empathic neural responses unfold over time in different empathy networks when viewing same-race and other-race individuals in dynamic painful conditions. We recorded magnetoencephalography signals from Chinese adults when viewing video clips showing a dynamic painful (or non-painful) stimulation to Asian and White models' faces to trigger painful (or neutral) expressions. We found that perceived dynamic pain in Asian models modulated neural activities in the visual cortex at 100 ms-200 ms, in the orbitofrontal and subgenual anterior cingulate cortices at 150 ms-200 ms, in the anterior cingulate cortex around 250 ms-350 ms, and in the temporoparietal junction and middle temporal gyrus around 600 ms after video onset. Perceived dynamic pain in White models modulated activities in the visual, anterior cingulate, and primary sensory cortices after 500 ms. Our findings unraveled earlier dynamic activities in multiple neural circuits in response to same-race (vs other-race) individuals in dynamic painful situations.

Magnetoencephalography in clinical practice / Magnetoencefalografia na prática clínica

ABSTRACT Magnetoencephalography (MEG) is a neurophysiological technique that measures the magnetic fields associated with neuronal activity in the brain. It is closely related but distinct from its counterpart electroencephalography (EEG). The first MEG was recorded more than 50 years ago and has technologically evolved over this time. It is now well established in clinical practice particularly in the field of epilepsy surgery and functional brain mapping. However, underutilization and misunderstanding of the clinical applications of MEG is a challenge to more widespread use of this technology. A fundamental understanding of the neurophysiology and physics of MEG is discussed in this article as well as practical issues related to implementation, analysis, and clinical applications. The future of MEG and some potential clinical applications are briefly reviewed.

RESUMO A magnetoencefalografia (MEG) é uma técnica neurofisiológica que mede os campos magnéticos associados à atividade neuronal no cérebro. A técnica é distinta da eletroencefalografia (EEG), porém está intimamente relacionada a ela. A primeira foi registrada há mais de 50 anos e evoluiu tecnologicamente ao longo do tempo. Está agora bem estabelecida na prática clínica, particularmente nos campos da cirurgia de epilepsia e mapeamento cerebral funcional. No entanto, a subutilização e a incompreensão das aplicações clínicas da MEG são um desafio para o uso mais amplo dessa tecnologia. Suas bases neurofisiológica e física são discutidas neste artigo, bem como questões práticas relacionadas à sua implementação, análise e aplicações clínicas. O futuro da MEG e algumas aplicações clínicas potenciais são brevemente revistos.

Key technologies for intelligent brain-computer interaction based on magnetoencephalography / 生物医学工程学杂志

Brain-computer interaction (BCI) is a transformative human-computer interaction, which aims to bypass the peripheral nerve and muscle system and directly convert the perception, imagery or thinking activities of cranial nerves into actions for further improving the quality of human life. Magnetoencephalogram (MEG) measures the magnetic field generated by the electrical activity of neurons. It has the unique advantages of non-contact measurement, high temporal and spatial resolution, and convenient preparation. It is a new BCI driving signal. MEG-BCI research has important brain science significance and potential application value. So far, few documents have elaborated the key technical issues involved in MEG-BCI. Therefore, this paper focuses on the key technologies of MEG-BCI, and details the signal acquisition technology involved in the practical MEG-BCI system, the design of the MEG-BCI experimental paradigm, the MEG signal analysis and decoding key technology, MEG-BCI neurofeedback technology and its intelligent method. Finally, this paper also discusses the existing problems and future development trends of MEG-BCI. It is hoped that this paper will provide more useful ideas for MEG-BCI innovation research.

Research progress of magnetoencephalography in neurological paroxysmal disease / 上海交通大学学报（医学版）

Neurological paroxysmal disease is a large group of clinical syndrome with a characteristic of sudden, recurrent, self-limiting. Clinically, routine biochemical or imaging examinations are usually with no significant abnormalities in the interictal period. However, magnetoencephalography (MEG), as an important electrophysiological tool in studying brain magnetic signals and monitoring brain electric activity, has highly temporal and spatial resolution for its noninvasive measurement of human brain with superconducting quantum interference. Therefore, it has been gradually used in researching for functional activities and mechanisms of the neuropsychiatric disorders and the advanced brain activity. There mainly reviewed the application and studies of MEG in epilepsy, paroxysmal kinesigenic dyskinesias and migraine.

Clinical value of combined magnetic resonance DWI and PWI in diagnosis of cerebral infarction at different stages / 中华老年心脑血管病杂志

Objective To stuy the clinical value of combined DWI and PWI in diagnosis of cerebral infarction (CI) at different stages.Methods One hundred and sixty-eight elderly CI patients were divided into hyperacute phase group (n =32),acute phase group (n =64),subacute phase group (n=45) and chronic phase group (n=27).Their DWI and PWI parameters and abnormal brain regions were compared.Results The ADC on DWI for injured lateral brain tissue was significantly lower than that on DWI for unjured lateral brain tissue in hyperacute phase group and acute phase group (0.39±0.08 vs 0.83±0.03;0.32±0.07 vs 0.91±0.05,P＜0.01).However,the ADC on DWI for the injured lateral brain tissue was significantly higher than that on DWI for the uninjured lateral brain tissue in subacute phase group and chronic phase group (1.54±0.34 vs 0.85±0.07,2.01±1.29 vs 0.90±0.05,P＜0.01).The PWI showed that the CBV was smaller and the CBF was slower while the MTT and TTP were longer in CI patients at different stages.DWI＜PWI,DWI＞PWI,and DWI=PWI in abnormal signal region were more frequently detected in hyperacute phase,acute phase subacute phase and chronic phase respectively.Conclusion PWI can show ischemic penumbra while DWI can highlight infarct foci in CI patients.Combined PWI and DWI can display the CBF in CI patients at different stages,and can thus provide reference for the clinical treatment of CI.

Study on functional connectivity between the subgenual anterior cingulate cortes and limbic cortices in predicting the efficacy of early antidepressant treatment outcome / 中华行为医学与脑科学杂志

Objective To explore the role of functional connectivity( FC) between the subgenual anterior cingulate cortes(sgACC) and limbic cortices in predicting the efficacy of early antidepressant treat-ment. Methods Resting state magnetoencephalography( MEG) data were collected from 32 patients with major depressive disorder(MDD) and 20 matched healthy control subjects at baseline.According to whether the HAMD17total score reduction rate reached 50% after 2 weeks,the patients were divided into responder group and non-responder group.The difference of the FC,the relationship between the FC and the change rate of HAMD17were explored. Results Compared with controls,MDD patients showed decreased connectivity of the sgACC with the right hippocampus(MNI coordinate:x＝30,y＝－3,z＝－24; F＝5.11,P＝0.028),the right amygdala(MNI coordinate:x＝22,y＝－2,z＝－15; F＝6.90,P＝0.012) and the left amygdala(MNI coordi- nate:x＝－24,y＝－6,z＝－16; F＝5.75,P＝0.020).Compared with non-responders,the connectivity of the sgACC with the right hippocampus(MNI coordinate:x＝30,y＝－3,z＝－24;F＝8.74,P＝0.0065),the right a-mygdala(MNI coordinate:x＝22,y＝－2,z＝－15; F＝12.417,P＝0.0016) were higher in responders.Pretreat-ment connectivity of the sgACC with the right hippocampus(r＝－0.50,P＝0.0066),the right amygdala(r＝－0.56,P＝0.0018) were negatively correlated with clinical improvement.ROC analyses confirmed the value of the connectivity of sgACC with the right hippocampus(area under curve(AUC)＝0.71,P＝0.042),the right amygdala(AUC＝0.73,P＝0.029) in classifying responders versus non-responders in 2 weeks of treatment. Conclusion The decreased FC of the sgACC with the right hippocampus and the right amygdala at baseline is associated with a better improvement,which can potentially serve as a treatment outcome biomarker in ear-ly curative effect of depression.

Observation of Auditory Perceptual and Visuo-Spatial Characteristic of a Patient with Hemangiopericytoma in Occipital Lobe: A Magnetoencephalography (MEG) Study / Jurnal Sains Kesihatan Malaysia

@#The present study discussed functional reorganization and alteration in respond to the slow-growing tumour,hemangiopericytoma in the occipital cortex. Visual evoked field (VEF) and auditory evoked field (AEF) usingmagnetoencephalography (MEG) was used to evaluate the source localization and brain activity. Results of VEF sourcelocalization show a typical brain waves. Brain activity of the occipital lobe demonstrate low activation in the ipsilateralto the tumour. However, result shows the activation on the contralateral hemisphere was high and bigger in activationvolume. AEF result shows an identical source localization and both side of the temporal lobe are activated. This resultsuggests that there is a positive plasticity in auditory cortex and slow-growing tumour can induce functional reorganizationand alteration to the brain.

Assessing Neuroplasticity Using Magnetoencephalography (MEG) in Patient with Left-Temporo-Parietal Pilocytic Astrocytomas Treated with Endoscopic Surgery / Jurnal Sains Kesihatan Malaysia

@#Neuroplasticity has been subjected to a great deal of research in the last century. Recently, significant emphasis has beenplaced on the global effect of localized plastic changes throughout the central nervous system, and on how these changesintegrate in a pathological context. The present study aimed to demonstrate the functional cortical reorganization beforeand after surgery using magnetoencephalography (MEG) in a participant with brain tumor. Results of Visual EvokedMagnetic Field (VEF) based on functional MEG study revealed significantly different of MEG N100 waveforms before andafter surgery. Larger and additional new locations for visual activation areas after the surgery were found suggestingneuroplasticity. The present study highlight a physiological plasticity in a teenage brain and the alterations regardingneural plasticity and network remodeling described in pathological contexts in higher-order visual association areas.

MEG and EEG dipole clusters from extended cortical sources

Data from magnetoencephalography (MEG) and electroencephalography (EEG) suffer from a rather limited signal-to-noise-ratio (SNR) due to cortical background activities and other artifacts. In order to study the effect of the SNR on the size and distribution of dipole clusters reconstructed from interictal epileptic spikes, we performed simulations using realistically shaped volume conductor models and extended cortical sources with different sensor configurations. Head models and cortical surfaces were derived from an averaged magnetic resonance image dataset (Montreal Neurological Institute). Extended sources were simulated by spherical patches with Gaussian current distributions on the folded cortical surface. Different patch sizes were used to investigate cancellation effects from opposing walls of sulcal foldings and to estimate corresponding changes in MEG and EEG sensitivity distributions. Finally, white noise was added to the simulated fields and equivalent current dipole reconstructions were performed to determine size and shape of the resulting dipole clusters. Neuronal currents are oriented perpendicular to the local cortical surface and show cancellation effects of source components on opposing sulcal walls. Since these mostly tangential aspects from large cortical patches cancel out, large extended sources exhibit more radial components in the head geometry. This effect has a larger impact on MEG data as compared to EEG, because in a spherical head model radial currents do not yield any magnetic field. Confidence volumes of single reconstructed dipoles from simulated data at different SNRs show a good correlation with the extension of clusters from repeated dipole reconstructions. Size and shape of dipole clusters reconstructed from extended cortical sources do not only depend on spike and timepoint selection, but also strongly on the SNR of the measured interictal MEG or EEG data. In a linear approximation the size of the clusters is proportional to the inverse SNR.

A wearable system for adaptation to left–right reversed audition tested in combination with magnetoencephalography

Exposure of humans to unusual spaces is effective to observe the adaptive strategy for an environment. Though adaptation to such spaces has been typically tested with vision, little has been examined about adaptation to left–right reversed audition, partially due to the apparatus for adaptation. Thus, it is unclear if the adaptive effects reach early auditory processing. Here, we constructed a left–right reversed stereophonic system using only wearable devices and asked two participants to wear it for 4 weeks. Every week, the magnetoencephalographic responses were measured under the selective reaction time task, where they immediately distinguished between sounds delivered to either the left or the right ear with the index finger on the compatible or incompatible side. The constructed system showed high performance in sound localization and achieved gradual reduction of a feeling of strangeness. The N1m intensities for the response-compatible sounds tended to be larger than those for the response-incompatible sounds until the third week but decreased on the fourth week, which correlated with the initially shorter and longer reaction times for the compatible and incompatible conditions, respectively. In the second week, disruption of the auditory-motor connectivity was observed with the largest N1m intensities and the longest reaction times, irrespective of compatibility. In conclusion, we successfully produced a high-quality space of left–right reversed audition using our system. The results suggest that a 4-week exposure to the reversed audition causes optimization of the auditory-motor coordination according to the new rule, which eventually results in the modulation of early auditory processing.

Functional role of somatosensory system to control voluntary movement / 体力科学

<p>A motor program for controlling one’s own movement requires sensory signals from the target body parts. Information for movement is provided by sensory feedback such as visual and somatosensory information. Previous studies indicated that cortical activity related to sensory response and perception is modified by movement executing mechanisms. The integration of sensory information and motor command is critical for motor control and recognition of one movement. However, this raises the issue of how central nervous system integrates motor command and sensory information whenever the intended movement is in progress. Preceding and during voluntary movement, the efference copy in relation to motor signal from motor related areas modified the information processing in somatosensory areas. This review introduces the research topics of sensorimotor integration and new findings according to recent studies of the somatosensory system in relation to sports science.</p>

Functional Neuroimaging in Neuro-Otology / 대한평형의학회지

Neuro-otologic symptoms such as dizziness, hearing loss, or tinnitus give rise to peripheral change-induced neuroplasticity or central pathology-induced structural or functional changes. In this regard, functional neuroimaging modalities such as positron emission tomography (PET), functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), quantitative electroencephalography (qEEG), or functional near infrared spectroscopy have provided researchers with possibility to observe neuro-otologic disease-induced central functional changes. Among these methods, PET and fMRI are advantageous over qEEG or MEG with regard to spatial resolution, while qEEG and MEG are advantageous over PET or fMRI with regard to temporal resolution. Also, fMRI or MEG is not suitable for patients with implanted devices, whereas PET is not ideal for repetitive measures due to radiation hazard. In other words, as these modalities are complementary to one another, researchers should choose optimum imaging modality on a case by case basis. Hereinafter, representative functional neuroimaging modalities and their application to neuro-otologic research will be summarized.

Multi-frequency magnetoencephalography study on alterations of resting-state neural networks in females with migraine at attack stage / 临床神经病学杂志

Objective To explore the alterations of resting-state neural networks in females with migraine at attack stage in low-and high-frequency ranges compared to healthy controls. Methods Resting-state magnetoencephalography data from 20 females with migraine ( migraine group ) and 20 age-and gender-matched healthy controls ( control group ) were collected to compute the neural network parameters through graph theory analysis.Independent samples t test was used to compare the difference of the network parameters between the two groups.The Pearson coefficient was used to assess the relationship between the abnormal network parameters and clinical manifestations of migraine.Results Compared with control group, females in migraine group at attack stage showed increased functional connectivity in the 0.1 -1 Hz, 4 -8 Hz, 12 -30 Hz, 30 -80 Hz band; increased shortest path length in the 80-250 Hz band; increased clustering coefficient and degree in the 0.1 -1 Hz band;decreased clustering coefficient and degree in the 4 -8 Hz, 12 -30 Hz band ( P<0.05 -0.01 ) .The functional connectivity of females with migraine at attack stage was positively correlated with number of years with migraine in the 12-30 Hz ( r=0.56, P=0.01 ) .Conclusion These results indicate that inherent neural networks are significantly impaired in low-and high-frequency ranges in females with migraine at attack stage and may contribute to the clinical manifestations of this disorder.

The primary explore of the damage of the executive control network in major depressive disorder:a dynamic causal model on magnetoencephalography / 中华行为医学与脑科学杂志

Objective To investigate the interconnection of the executive control network in major depressive disorder when they recognized the sad facial stimuli,and to discuss the aberrant mechanism of emotion processing.Methods Twenty major depressive patients and 20 well-matched healthy volunteers participated in the experiment.The brain actions of all subjects were recorded by the magnetoencephalography (MEG) when they were required to distinguish the emotion face.Based on prior knowledge,the interested brain area consisted of the primary visual cortex (V1),the orbitofrontal cortex(OFC),the dorsolateral prefrontal cortex (DLPFC),the anterior cingulated cortex (ACC).Then constructing three competing models to select an optimal model by the method of dynamic causal model(DCM),finally the differences of the effective connections of the optimal model between the depressed patients and healthy controls were analyzed.Results According to the results of Bayesian model selection (BMS),model 1 had the most exceedance probability of 0.80 with the features that there were bidirectional modulatory connections between the OFC,ACC and DLPFC.Given the best model,the parameters of effective connectivity of the optimal model were extracted,and then two-sample t-test over the model 1 was adopted.The modulatory effective connectivity from the OFC to the DLPFC in both hemisphere(t=-2.73,P=0.0096;t=-3.01,P=0.0046) and the OFC to the ACC (t=-2.93,P=0.0057) in the left hemisphere were significantly reduced in MDD.Conclusion There exists abnormal function of executive control network in depressed patients,the decreased effective connections between the OFC and the DLPFC,as well as the OFC and the ACC,may have correlation with the negative

The post cingulate's role in triggering voluntary swallowing / 中华物理医学与康复杂志

Objective To investigate the function of the post cingulate in triggering voluntary swallowing by examining the activated areas in the brain of dysphagic patients with and without delayed pharyngeal swallowing using magnetoencephalography.Methods Videofluoroscopy was used to detect the latency of pharyngeal swallowing of 6 dysphagic patients.Magnetoencephalography (MEG) was used to monitor the whole course of voluntary swallowing,and an equivalent current dipole was applied to the activated areas of the brain 2500 ms before the subconscious electromyographic signals appeared.Magnetic resonance imaging (MRI) was performed just after the magnetoencephalography.A magnetic source image (MSI) was generated by overlaying the MRI and MEG results.Results The MSIs of five of the patients were derived.Three had delayed initiation of pharyngeal swallowing (with the latency being 0.03-0.12 s) and the other two showed normal latency during pharyngeal swallowing.In the former 3 patients,the post cingulate was activated at 1426 ms,1138 ms and 1675 ms before the burst of electromyography signals,which was later than that of the anterior cingulate and the insular cingulate.The 2 patients without delayed pharyngeal swallowing had their post cingulate activated at 1971 ms and 2483 ms before or at almost the same time as the anterior cingulate and insular.Conclusion Post cingulate activation occurs later than that of the anterior cingulate and insular in patients with delayed pharyngeal swallowing,the reverse of normal swallowing.This result indicates that the post cingulate may play an important role in triggering voluntary swallowing.

Magnetoencephalography Phantom Comparison and Validation: Hospital Universiti Sains Malaysia (HUSM) Requisite

Background: Magnetoencephalography (MEG) has been extensively used to measure small-scale neuronal brain activity. Although it is widely acknowledged as a sensitive tool for deciphering brain activity and source localisation, the accuracy of the MEG system must be critically evaluated. Typically, on-site calibration with the provided phantom (Local phantom) is used. However, this method is still questionable due to the uncertainty that may originate from the phantom itself. Ideally, the validation of MEG data measurements would require cross-site comparability. Method: A simple method of phantom testing was used twice in addition to a measurement taken with a calibrated reference phantom (RefPhantom) obtained from Elekta Oy of Helsinki, Finland. The comparisons of two main aspects were made in terms of the dipole moment (Qpp) and the difference in the dipole distance from the origin (d) after the tests of statistically equal means and variance were confirmed. Result: The result of Qpp measurements for the LocalPhantom and RefPhantom were 978 (SD24) nAm and 988 (SD32) nAm, respectively, and were still optimally within the accepted range of 900 to 1100 nAm. Moreover, the shifted d results for the LocalPhantom and RefPhantom were 1.84 mm (SD 0.53) and 2.14 mm (SD 0.78), respectively, and these values were below the maximum acceptance range of within 5.0 mm of the nominal dipole location. Conclusion: The local phantom seems to outperform the reference phantom as indicated by the small standard error of the former (SE 0.094) compared with the latter (SE 0.138). The result indicated that HUSM MEG system was in excellent working condition in terms of the dipole magnitude and localisation measurements as these values passed the acceptance limits criteria of the phantom test.

The MEG and clinical features of bipolar depression / 中国神经精神疾病杂志

Objective To explore the resting state cortical activity and frontal asymmetry in alpha oscillations in bipolar depressive patients and its relationship with clinical symptoms. Methods Twelve bipolar depressive patients (pa?tient group) and twenty-four well-matched healthy volunteer (control group) were underwent whole head MEG recording. Individual spectral power and frontal asymmetry index were calculated by using permutation test to discover the differenc?es in δ, θ, α1, α2, α3, β bands between the two groups among the regions of interested (bilateral central, frontal lobe, temporal lobe, parietal lobe, occipital lobe). The correlation analysis were used to analyze the association between power of brain regions with significant difference and the Hamilton depression rating scale17 scores as well as factor items in patients. Results Compared with the control group, the activity of various regions was increased in the patient group as follows:theδband in the left central and left occipital lobes, theθband in the left occipital lobe, theβband in left cen?tral, right frontal, left parietal lobe and right parietal lobe. The power ofα2 andα3 frequency bands was decreased in the bilateral temporal lobes (P<0.05, uncorrected). A negative correlation was observed between the right temporalα3 power and recognition item scores for bipolar depression (P<0.05). Conclusion The present study suggests that bipolar depres?sive patients have impaired neural activity at many bands and the symptom of cognitive impairment may be associated with dysfunction ofα3 band.

Magnetoencefalografía: mapeo de la dinámica espaciotemporal de la actividad neuronal / Magnetoencephalography: mapping the spatiotemporal dynamics of neuronal activity

La magnetoencefalografía es una técnica de neuroimagen no invasiva que mide, con gran exactitud temporal, los campos magnéticos en la superficie de la cabeza producidos por corrientes neuronales en regiones cerebrales. Esta técnica es sumamente útil en la investigación básica y clínica, porque además permite ubicar el origen de la actividad neural en el cerebro. En esta revisión se abordan aspectos básicos de la biofísica del método y se discuten los hallazgos sobre procesos como la percepción del habla, la atención auditiva y la integración de la información visual y auditiva, que son importantes en la investigación. Igualmente, se ilustran sus ventajas, sus limitaciones y las nuevas tendencias en la investigación con magnetoencefalografía.

Magnetoencephalography is a noninvasive imaging technique that measures the magnetic fields on the surface of the head --produced by neuronal currents in brain regions -- and provides highly accurate temporal information. Magnetoencephalography is extremely useful in basic and clinical research as it can also locate the sources of neural activity in the brain. This review chiefly approaches biophysics-related aspects of the method; findings are also discussed on issues such as speech perception, auditory attention and integration of visual-auditory information, which are quintessential in this type of research. Lastly, this review discusses the benefits and limitations of magnetoencephalography and outlines new trends in research with this technique.

Advances in multimodality neuroimaging studies of autism spectrum disorders / 中华实用儿科临床杂志

Autism spectrum disorders (ASD) is a complex,behaviorally defined,mental disorder with uncertain causes although it is more likely caused by the interaction of genetic and environmental factors.ASD's heterogeneity in pathology and phenotype makes it difficult to accurately diagnose individual patients.Therefore,it is an urgent need to develop effective tools for screening susceptible individuals for early diagnosis and treatment.This paper reviews recent neuroimaging and imaging genetic studies of ASD.The existing results indicate that proper combination of multimodal neuroimaging techniques and genetic technology is expected to reveal the pathological mechanism of ASD and might help find objective biomarkers for achieving an early and accurate diagnosis of ASD.

Extraction method of the magnetoencephalography somatosensory evoked signals based on the MP decomposition / 中国医学装备

Objective:Matching pursuit algorithm(MAP),for its good parametric characterization, is applied in Magnetoencephalography(MEG) to study time-frequency distribution. Methods:This paper proposes to apply a high-resolution time-frequency analysis algorithm, the matching pursuit (MP), to extract detailed time-frequency components of SEF signals. Results: Experimental results on cortical SEF signals of several normal subjects show that a series of stable SEF time components can be identified using the MP decomposition algorithm. Conclusion:This study shows that there is a set of stable and minute time-frequency componentsin SEF signals, which are revealed by the MP decomposition. These stable SEF components have specific localizations in the time domain and may provide a reliable index for clinical research of brain function and brain disease pathogenesis.