Overexpression of lncRNA-MEG3 inhibits endometrial cell proliferation and invasion via miR-21-5p/DNMT3B/Twist

Abstract Recent studies have found that lncRNA-MEG3(MEG3) plays an important role in the development of EMs (Endometriosis), but the specific mechanism needs to be further explored. This study aimed to investigate the effect of MEG3 on the proliferation, invasion of EMs cells. The authors used RT-qPCR to detect the expression of MEG3 and miR-21-5p in EMs tissues and hESCs cells, MTT and Transwell to detect cell proliferation and invasion, western blotting assay to detect the expression of DNMT3B and Twist, MSP to detect the methylation of Twist. The present study's detection results showed that MEG3 was lowly expressed in EMs tissues and hESCs cells, and overexpression of MEG3 could down-regulate miR-21-5p and inhibit endometrial cell proliferation and invasion. In addition, overexpression of MEG3 upregulated the expression of DNMT3B and promoted the methylation of TWIST. In conclusion, the present findings suggest that MEG3 is downregulated in EMs tissues, and overexpression of MEG3 can promote the activity of DNA methyltransferase DNMT3B by downregulating miR-21-5p, thereby promoting the methylation of Twist, downregulating Twist level to inhibits hESCs cells proliferation and invasion.

Overexpression of lncRNA MEG3 inhibits proliferation and invasion of glioblastoma U251 cells / 南方医科大学学报

OBJECTIVE@#To investigate the effects of overexpression of long noncoding RNA (lncRNA) MEG3 on the proliferation and invasion of glioblastoma U251 cells by suppressing the expression of hypoxia inducible factor 1@*METHODS@#The expression of lncRNA MEG3 and HIF1@*RESULTS@#The expression of MEG3 was significantly lower and HIF1@*CONCLUSIONS@#MEG3 overexpression inhibits the proliferation and invasion of U251 cells through suppressing the expression of HIF1

Effect of lncRNA MEG3 on radiosensitivity of nasopharyngeal carcinoma cells by down-regulating miR-7-5p expression / 中华放射肿瘤学杂志

Objective To investigate the effect and underlying mechanism of lncRNA MEG3 on the radiosensitivity of nasopharyngeal carcinoma cells.Methods this experiment,overexpression control group,MEG3 overexpression group,miR-NC inhibition group,miR-7-5p inhibition group,overexpression control+4 Gy group,MEG3 overexpression+4 Gygroup,miR-NC inhibition+4 Gy group,miR-7-5p inhibition+4 Gy group,MEG3 overexpression + miR-NC overexpression group,MEG3 overexpression + miR-7-Sp overexpression group were established.The expression of miR-7-5p and MEG3 was detected by qRT-PCR.The radiosensitivity of nasopharyngeal carcinoma cells was measured by clone formation assay.Cell apoptosis was assessed by flow cytometry.The fluorescence activity was evaluated by dual luciferase reporter assay.Results MEG3 was lowly expressed in nasopharyngeal carcinoma tissues and cells.Overexpression of MEG3 and inhibition of miR-7-5p expression increased the radiosensitivity of nasopharyngeal carcinoma cells and promoted radiation-induced cell apoptosis.MEG3 could targetedly regulate the miR-7-5p expression.Overexpression of miR-7-5p reversed the effect of overexpression of MEG3 on the sensitization of nasopharyngeal carcinoma cells and the promotion of apoptosis induced by radiation exposure.Conclusions Overexpression of MEG3 increases the radiosensitivity of nasopharyngeal carcinoma cells and promotes radiation-induced cell apoptosis.The mechanism may be related to the down-regulation of miR-7-5p expression.

The effects of long non-coding RNA MEG3 on endoplasmic reticulum stress-induced colon cancer cell apoptosis and the growth of transplanted human colonic carcinoma in nude mice / 西安交通大学学报(医学版)

Objective: To investigate the effects of maternally expressed gene 3 (MEG3) on endoplasmic reticulum stress-induced colon cancer cell apoptosis and the growth of transplanted human colonic carcinoma in nude mice. Methods:Colon cancer cell lines with the lowest expression level of MEG3 were screened by RT-PCR; negative control cell lines were constructed and stable transfectants were screened. RT-PCR was performed for measuring the lncRNA level of MEG3, cell growth was measured by CCK8, cell apoptosis was determined by Hoechst. Western blot was used to determine the protein levels of Bcl-2, Bax, cleaved Caspase-9, p-PERK, ATF-4, p-EIF2α, CHOP, cleaved Caspase-12, p-AMPK, AMPK, p-mTOR, and mTOR. The expression of CHOP was silenced by si-CHOP, and then cell apoptosis was determined by Hoechst. Transplanted human colonic carcinoma in nude mice was established and tumor volume was measured, tumor growth was measured by IHC Ki67, cell apoptosis was determined by TUNNEL, Western blot was used to determine the protein levels of CHOP, cleaved Caspase-12, and cleaved Caspase-3. Results: The SW480 cell line had the lowest expression level of MEG3 and was used in subsequent experiments. In cytological experiments, compared with those in control group, the cell growth, protein levels of Bcl-2 and ratio of p-mTOR/mTOR were decreased significantly; the apoptosis rate, protein levels of Bax, cleaved Caspase-9, p-PERK, ATF-4, p-eIFα, CHOP and cleaved Caspase-12 and ratio of p-AMPK/AMPK increased notably; the expression of CHOP was silenced; the apoptosis induced by pc-MEG3 could be significantly decreased. In animal experiments, compared with control group, the tumor volume and number of positive cells of Ki67 decreased significantly; the apoptosis rate, protein levels of CHOP, cleaved Caspase-12 and cleaved Caspase-3 increased markedly. Conclusion: MEG3 can promote colon cancer cell apoptosis by endoplasmic reticulum stress, and CHOP may play a crucial role in the process. Furthermore, AMPK/mTOR is also involved in the regulation of apoptosis by MEG3.

DNMT1 protein promotes retinoblastoma proliferation by silencing MEG3 gene / 南方医科大学学报

OBJECTIVE@#To investigate whether DNMT1 protein induces retinoblastoma proliferation by silencing MEG3 gene.@*METHODS@#Two retinoblastoma cell lines (HXO-RB44 and SO-RB50) and a normal human retinal pigment epithelial (RPE) cell line were transfected with the plasmid pcDNA-DNMT1 or si-DNMT1 for up-regulating or interference of DNMT1 expression, and with pcDNA-MEG3 or si-MEG3 for up-regulating or interference of MEG3 expression. Western blotting was used to detect the changes in the expression of DNMT1 protein in the transfected cells, and CCK-8 and EdU assays were used to detect the changes in cell proliferation. Real-time quantitative PCR (qRT-PCR) was performed to detect MEG3 expression in SO-RB50 and HXO-RB44 cells after transfection, and the methylation level of MEG3 gene promoter after interference of DNMT1 expression was detected using methylation-specific PCR.@*RESULTS@#SO-RB50 and HXO-RB44 cells showed significantly increased expression of DNMT1 protein as compared with normal RPE cells ( < 0.05). In HXO-RB44 cells, transfection with pcDNADNMT1 resulted in significantly increased expression of DNMT1 protein, enhanced cell proliferation ability, and significantly reduced expression of MEG3 ( < 0.05). In SO-RB50 cells, transfection with si-DNMT1 significantly reduced the expression of DNMT1 protein, suppressed the cell proliferation, and increased MEG3 expression ( < 0.05). Interference of DNMT1 significantly reduced the methylation level of MEG3 gene promoter. After reversing the regulatory effect of DNMT1 on MEG3 gene, DNMT1 protein showed significantly weakened ability to regulate retinoblastoma cell proliferation ( < 0.05).@*CONCLUSIONS@#In retinoblastoma cells, the up-regulation of DNMT1 protein induces promoter methylation and inactivation of MEG3 gene and eventually leads to abnormal cell proliferation.

Effect of lncRNA MEG3 on the malignant biological behaviors of cervical cancer standard regimen for advanced colorectal cancer / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To explore the regulatory effect of lncRNA maternal imprinting gene 3 (MEG3) on proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of cervical cancer cells via miR-9-5p/SOCS5 axis. Methods: A total of 20 pairs of cancer and para-cancerous tissue specimens resected from cervical cancer patients in Chongqing Hospital of Traditional Chinese Medicine from January 2017 to June 2019 were collected for this study. Using liposome transfection technology, pcDNA3.1-MEG3,si-MEG3, miR-9-5p mimics, miR-9-5p inhibitor and their control plasmids were transfected into cervical cancer HeLa and SiHa cells respectively to construct overexpression and silence cell model. qPCR was used to detect the expression levels of MEG3, miR-9-5p and SOCS5 in cervical cancer tissues and cell lines. CCK-8 method and Transwell chamber method were used to detect cell proliferation, migration and invasion ability. The expression levels of E-cadherin and vimentin in cells were detected by cellular immunofluorescence experiments. Target genes were predicted through the Online Bioinformatics TargetScan database. Dual luciferase reporter gene assay was used to verify the targeting relationship between miR-9-5p and MEG3, SOCS5, respectively. Results: Compared with para-cancerous tissues and cervical epithelial HcerEpic cells, the expressions of MEG3 and SOCS5 were significantly down-regulated and the expression of miR-9-5p was significantly up-regulated in cervical cancer tissues and cell lines (all P<0.01). TargetScan database analysis and Dual luciferase reporter gene assay confirmed the targeting relationship between miR-9-5p and MEG3 or SOCS5. MEG3 and SOCS5 significantly inhibited while miR-9-5p significantly promoted cell proliferation, migration and invasion ability (all P<0.01). MEG3 and SOCS5 promoted E-cadherin expression and inhibited vimentin expression, while miR-9-5p inhibited E-cadherin expression and promoted vimentin expression (P<0.05 or P<0.01). Conclusion: lncRNA MEG3 regulates proliferation, migration, invasion and EMT of cervical cancer cells via miR-9-5p/SOCS5 axis.

Eros na constituição do objeto estético: fragmentos de uma escuta a fim de entender melhor o que eu quero dizer / Eros in constitution of the aesthetical object: fragments from a listening to better understand what I want to say / Eros en la constitución del objeto estético: fragmentos de una escucha para mejor entender lo que quiero decir / Eros dans la constitution de l'objet esthétique: fragments de l'écoute pour mieux comprendre ce que je veux dire

Neste trabalho faço uma exploração sobre o objeto estético, descrito por Meg Harris Williams como um processo da mentalidade estética. Tecendo associações entre poemas, experiências emocionais e sonhos, vou construindo um texto, em que as ideias nascidas são compreendidas como função dos objetos internos que, no recolhimento de sua câmera nupcial, criam símbolos, pensamentos oníricos e pensamentos de cuja matéria se fazem pensamentos.

In this paper I explore the aesthetic object described by Meg Harris Williams as a process of the aesthetic mindset. Weaving associations among poems, emotional experiences and dreams I build a text where the born ideas are understood as a function of the internal objects that, in the recollection of their "bridal camera", create symbols, dream thoughts and thoughts from whose matter thoughts are made.

En este artículo exploro el objeto estético descrito por Meg Harris Williams como un proceso de mentalidad estética. Tejiendo asociaciones entre poemas, experiencias emocionales y sueños construyo un texto donde las ideas nacidas se entienden como una función de los objetos internos que, en el recuerdo de su "cámara nupcial", crean símbolos, pensamientos y pensamientos de los sueños de los cuales están hechos los pensamientos.

Dans cet article, j'explore l'objet esthétique décrit par Meg Harris Williams en tant que processus de la mentalité esthétique. Tissant des associations entre poèmes, expériences émotionnelles et rêves, je construis un texte dans lequel les idées nées sont comprises comme une fonction des objets internes qui, dans le souvenir de leur "chambre nupciale", créent des symboles, des pensées de rêve et des pensées à partir desquelles des pensées sont créées.

lncRNA MEG3 inhibits the growth of hepatocellular carcinoma cells by sponging miR-9-5p to upregulate SOX11

The long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3), a tumor suppressor, is critical for the carcinogenesis and progression of different cancers, including hepatocellular carcinoma (HCC). To date, the roles of lncRNA MEG3 in HCC are not well illustrated. Therefore, this study used western blot and qRT-PCR to evaluate the expression of MEG3, miR-9-5p, and Sex determining Region Y-related HMG-box 11 (SOX11) in HCC tissues and cell lines. RNA pull-down and luciferase reporter assay were used to evaluate these molecular interactions. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and flow cytometry detected the viability and apoptosis of HCC cells, respectively. The results showed that MEG3 and SOX11 were poorly expressed but miR-9-5p was highly expressed in HCC. The expression levels of these molecules suggested a negative correlation between MEG3 and miR-9-5p and a positive correlation with SOX11, confirmed by Pearson's correlation analysis and biology experiments. Furthermore, MEG3 could combine with miR-9-5p, and SOX11 was a direct target of miR-9-5p. Moreover, MEG3 over-expression promoted cell apoptosis and growth inhibition in HCC cells through sponging miR-9-5p to up-regulate SOX11. Therefore, the interactions among MEG3, miR-9-5p, and SOX11 might offer a novel insight for understanding HCC pathogeny and provide potential diagnostic markers and therapeutic targets for HCC.

Edible active coatings incorporated with Cinnamomum cassia and Myristica fragrans essential oils to improve shelf-life of minimally processed apples / Revestimentos comestíveis ativos contendo óleos essenciais de Cinnamomum cassia e Myristica fragrans para aumentar a vida útil de maçãs minimamente processadas

ABSTRACT: The effect of the incorporation of cinnamon (Cinnamomum cassia) and nut meg (Myristicafragrans) essential oils in alginate-based edible coatings that were applied on minimally processed apples, is reported. The minimum inhibitory concentrations were 1.25mg.mL-1 (cinnamon) and 2.50mg.mL-1 (nutmeg), against both Escherichia coli and Penicillium commune. Over storage periods there was a significant reduction in the E. coli and P. commune counts compared to the control. The extent of enzymatic browning was also significantly reduced in the coated samples. In the coated minimally processed apples sensory tests, the flavor had the lowest rating of the properties analyzed, for both treatments, followed by aroma and firmness.

RESUMO: O efeito da incorporação dos óleos essenciais de canela (Cinnamomum cassia) e noz-moscada (Myristicafragrans) em revestimentos comestíveis à base de alginato, aplicados em maçãs minimamente processadas é apresentado. As concentrações inibitórias mínimas foram de 1,25mg.mL-1 (canela) e 2,50mg.mL-1 (noz-moscada), contra Escherichia colie Penicillium commune. Durante o armazenamento, houve redução significativa nas contagens de E.coli e P. Commune em comparação com o controle. A extensão do escurecimento enzimático também foi significativamente reduzida nas amostras revestidas. Nas análises sensoriais, o sabor dos óleos essenciais apresentou a menor classificação das propriedades analisadas, tanto para os óleos essenciais, quanto para aroma e firmeza.

Promoter methylation of MEG3 gene in hepatocellular carcinoma and its clinical significance / 肿瘤研究与临床

Objective To investigate promoter methylation state of MEG3 gene in hepatocellular carcinoma and its clinical significance. Methods Methylation-specific polymerase chain reaction (MSP) was performed to detect methylation of MEG3 promoter in 58 cases of hepatocellular carcinoma tissues and 20 cases of normal control from December 2014 to December 2016 in Shanxi Provincial Cancer Hospital, and to analyze the relationship between methylation and the clinicopathological features of the patients. Results The methylation incidence rate of MEG3 promoter in hepatocellular carcinoma tissues (55.2 %, 32/58) was higher than that in normal liver tissue (25.0 %, 5/20), and there was a significant statistical difference (χ2=6.72,P =0.02).There was no significant difference in the incidence of MEG3 methylation of the patients with different age, gender, α-fetoprotein levels, tumor number and differentiation (all P> 0.05). There was a significant difference in the incidence of MEG3 methylation of the patients with different tumors diameter, liver cirrhosis, hepatitis B surface antigen (HBsAg), TNM staging and distant metastasis (all P< 0.05). Conclusion Aberrant promoter methylation in MEG3 genes may be associated with the occurrence of hepatocellular carcinoma,tumor diameter,liver cirrhosis,HBsAg,TNM staging and distant metastasis.

Revision and redesign of the MEG standards / 中华医院管理杂志

Described in the paper are the outcomes and progress of the MEG standards in six years, along with the imperativeness and revision pathways of the standards for the purpose of further promoting the level of HIT development in China.

Melatonin prevents endothelial cell pyroptosis via regulation of long noncoding RNA MEG3/miR-223/NLRP3 axis / 中国药理学与毒理学杂志

OBJECTIVE To investigate the anti-pyroptotic effects of melatonin in atherosclerotic endothelium and to elucidate the potential mechanisms.METHODS ApoE-/-mice were randomly divid-ed into four groups (n=8): the normal-diet group (ND), the normal-diet group treated with melatonin (10 mg·kg-1)(ND+MLT),the high-fat-diet group(HFD),and the high-fat-diet group treated with melatonin (HFD+MLT).After 12 weeks,the expression levels of pyroptosis related genes including NLRP3,ASC, cleaved-caspase 1,GSDMD-N,IL-1β and IL-18 were examined in aortic endothelium by Western blotting, qRT-PCR and immunofluorescent staining.Besides,levels of MEG3 and miR-223 were also tested by qRT-PCR.The interaction between MEG3 and miR-223 was detected by luciferase assay.For in vitro study,human aortic endothelial cells(HAECs)were transiently transfected with miR-223 mimic,miR-223 inhibitor (AMO-223), MEG3-overexpressing plasmid or negative controls. After 6 h of transfection, the medium was replaced by fresh medium with or without ox-LDL(25 μg·mL-1)for 24 h and then treated with or without melatonin (10 μmol·L-1) for 48 h. Cell pyroptosis was evaluated by Hoechst 33342/PI staining and differentially expressed pyroptosis related genes. RESULTS Melatonin markedly reduced the atherosclerotic plaque in aorta of ApoE-/- mice. Meanwhile, melatonin also attenuated the expression NLRP3, ASC, cleaved-caspase1, NF-κB/GSDMD, GSDMD-N termini, IL-1β, and IL-18 in aortic endo-thelium.Consistent anti-pyroptotic effects were also observed in ox-LDL-treated HAECs.We found that lncRNAMEG3 enhanced pyroptosis in HAECs. Moreover, MEG3 acted as an endogenous sponge by sequence complementarity to suppress the function of miR-223 and to increase NLRP3expression and enhance endothelial cell pyroptosis. Furthermore, knockdown of miR-223 blocked the anti-pyroptotic actions of melatonin in ox-LDL-treated HAECs. CONCLUSION Melatonin prevents endothelial cell pyroptosis via MEG3/miR-223/NLRP3 axis in atherosclerosis and therefore melatonin replacement might be considered a new strategy for protecting endothelium against pyroptosis thereby for the treat-ment of atherosclerosis associated with pyroptosis.

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.

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.

Expression and clinical significance of MEG3 and GAS5 in the colorectal cancer / 中国现代普通外科进展

Objective:To detect the expression of long non-coding RNA (Long non-coding RNA,IncRNA) maternally expressed gene 3 (maternally expressed gene 3,MEG3),specific growth inhibitor 5 (Growth arrest-specific 5,GAS5) and to analyze the correlation between GAS5 and cyclin P21,E2F1,so as to investigate the mechanism of GAS5.Methods:From December 2014 to December 2015,63 consecutive Patients with colorectal cancer admitted to Qingdao Municipal Hospital for surgical treatment were included into our study.We collect colorectal cancer tissues and paired normal tissues.We tested the relative expression of MEG3,GAS5 genes by real-time quantitative PCR (RT-PCR),and Western blot was used to detect the expression of P21 and E2F1 in colorectal cancer and to evaluate their correlations with GAS5.Results:The expression of MEG3 in cancer (7.76 ± 1.38) was lower than that in normal tissues(9.52 ± 1.31)P＜0.052.The expression of GAS5 was decreased in cancer tissues (3.98 ± 1.15) relative to the normal (6.21 ± 1.33)P＜0.05.3.It showed that there were positive relationships between P21 and GAS5(r=0.410,P=0.001),and there were negative relationships between E2F1 and GAS5(r=-0.366,P=0.003).Conclusions:MEG3 and GAS5 were decreased in colorectal cancer,suggesting that they play inhibiting effects on the cancer.P21 and E2F1 are important target spots that GAS5 give play to the role of tumor suppressor.

LncRNA-MEG3 mediated apoptosis of retinoblastoma by regulating P53 pathway / 眼科新进展

Objective To investigate whether MEG3 involved in the development of retinoblastoma by down-regulating the expression of P53 protein.Methods The MEG3 expression of retinoblastoma tissues and corresponding non-tumor tissues were detected by quantitative real-time PCR (qRT-PCR).Retinoblastoma cell lines SO-RB50 or HXO-RB44 were transfected with pcDNA-MEG3 or siRNA-MEG3,after which cell apoptosis was tested by flow cytometry and P53 protein expression was tested by Western blot.Results MEG3 expression of retinoblastoma tissues was significantly reduced compared with corresponding non-tumor tissues(P =0.014).MEG3 level was significantly increased in pcDNA-MEG3 transfected SO-RB50 cells (P =0.002) and significantly decreased in siRNA-MEG3 transfected HXO-RB44 cells (P =0.004).Flow cytometry showed that the SO-RB50 cells apoptosis was significantly increased with the MEG3 over-expression(P ＜ 0.05),as well as the HXO-RB44 cells apoptosis was significantly decreased with the MEG3 knockdown(P ＜ 0.05),compared with the control group,respectively.Furthermore,Western blot showed that P53 protein level was significantly increased after SO-RB50 transfected with pcDNA-MEG3 (P ＜ 0.05),while significantly decreased after HXO-RB44 transfected with siRNA-MEG3 (P ＜ 0.05),compared with the control group,respectively.Conclusion MEG3 is down-regulated in retinoblastoma,affect the development of retinoblastoma,and may induce the retinoblastoma cell apoptosis by promoting the expression of P53 protein.

Statistical non-parametric mapping in sensor space

Establishing the significance of observed effects is a preliminary requirement for any meaningful interpretation of clinical and experimental Electroencephalography or Magnetoencephalography (MEG) data. We propose a method to evaluate significance on the level of sensors whilst retaining full temporal or spectral resolution. Input data are multiple realizations of sensor data. In this context, multiple realizations may be the individual epochs obtained in an evoked-response experiment, or group study data, possibly averaged within subject and event type, or spontaneous events such as spikes of different types. In this contribution, we apply Statistical non-Parametric Mapping (SnPM) to MEG sensor data. SnPM is a non-parametric permutation or randomization test that is assumption-free regarding distributional properties of the underlying data. The method, referred to as Maps SnPM, is demonstrated using MEG data from an auditory mismatch negativity paradigm with one frequent and two rare stimuli and validated by comparison with Topographic Analysis of Variance (TANOVA). The result is a time- or frequency-resolved breakdown of sensors that show consistent activity within and/or differ significantly between event or spike types. TANOVA and Maps SnPM were applied to the individual epochs obtained in an evoked-response experiment. The TANOVA analysis established data plausibility and identified latencies-of-interest for further analysis. Maps SnPM, in addition to the above, identified sensors of significantly different activity between stimulus types.

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.

Non-magnetic compliant finger sensor for continuous fine motor movement detection

A non-magnetic MEG compatible device has been developed that provides continuous force and velocity information. Combined with MEG, this device may find utility in characterizing brain regions associated with force and velocity relative to individual digits or movement pattern. 15 healthy right-handed participants were given visual cues to perform random finger movements on the prototype finger sensor for 21 s and then rest for 21 s (7 times). Respective finger flexion data were obtained, during 151-channel MEG brain scanning, by feeding the signal from finger sensor into four input Analog to Digital Converter (ADC) channels in the MEG hardware. The source activity was reconstructed in beta band using a Linearly Constrained Minimum Variance (LCMV) beamformer in the beta band. The ADC channels were used as regressors for a continuous time General Linear Model (GLM) and a Region of Interest (ROI) was identified to examine activity. MEG analysis showed bilateral activation in the primary motor cortex region. Because individual digits could be isolated in the ADC data, somatotopy of the fingers were observed consistent with the homunculus except pinky finger. The total span was calculated to be 5.5662 mm. The study confirms that the finger sensor is magnetically compatible with MEG measurements and may potentially provide a means to study complex sensorimotor functions. Improved isolation of individual digit information along with the use of machine learning algorithms can help retrieve more accurate results.

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.