Neurology & clinical neurophysiology : NCN最新文献_第3页

Technique for the direct measurement of DC-like magnetic biosignals demonstrated by the cold reflex of the abdomen. 直接测量由腹部冷反射证明的直流电样磁生物信号的技术。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

A Schnabel, F Thiel, W Mueller, M Burghoff

引用次数: 0

Volumetric estimation of functional brain regions in small children using spatially filtered magnetoencephalography: differentiating thumb from middle finger. 使用空间过滤脑磁图对儿童脑功能区域的体积估计:区分拇指和中指。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

J Xiang, S Holowka, H Qiao, B Sun, S Chuang

{"title":"Volumetric estimation of functional brain regions in small children using spatially filtered magnetoencephalography: differentiating thumb from middle finger.","authors":"J Xiang, S Holowka, H Qiao, B Sun, S Chuang","doi":"","DOIUrl":"","url":null,"abstract":"It is difficult to localize the somatosensory cortex in children under 6 years using magnetoencephalography (MEG) with conventional median nerve stimulation. One main reason is that MEG data recorded from small children have poor signal-to-noise ratio due to their small heads and short hands. To find a better approach, this study investigated neuromagnetic activities following finger stimulation using spatially filtered MEG. Four healthy children have been studied with a whole cortex MEG system. Electric stimulation was applied to the thumb and the middle fingers with two Digital Rings. Two trials were recorded for each hand. Focal increases of spectral power were localized using spectrogram and synthetic aperture magnetometry (SAM). A clear response at a latency of 21 ms was identified in 3 children (3/4). Dipole modeling localized the somatosensory cortex in 2 children (2/4). SAM successfully localized the somatosensory cortex in 4 children (4/4). Interestingly, the functional region estimated for the thumb was significantly larger than that of the middle finger (p < 0.01). However, it is possible that this effect is due to a larger source amplitude rather than larger source volume. Our results demonstrated that the developed approach could map the somatosensory cortex in children ranging in age from 3 to 6. To our knowledge, this is the first report using non-invasive methods to provide quantitative data indicating that the functional area of the thumb is larger than that of the middle finger in small children.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"110"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The MMN is a derivative of the auditory N100 response. MMN是听觉N100反应的衍生物。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

P J C May, H Tiitinen

引用次数: 0

Fetal magnetocardiography: the clinician's viewpoint. 胎儿心脏磁图:临床医生的观点。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

N Sreeram, K Brockmeier

引用次数: 0

Evaluation of magnetocardiography indices in patients with cardiac diseases. 心脏病患者心磁图指标的评价。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

M M Budnyk, V I Kozlovsky, L A Stadnyuk, O M Zahrabova, T M Ryzhenko, T V Getman

{"title":"Evaluation of magnetocardiography indices in patients with cardiac diseases.","authors":"M M Budnyk, V I Kozlovsky, L A Stadnyuk, O M Zahrabova, T M Ryzhenko, T V Getman","doi":"","DOIUrl":"","url":null,"abstract":"The purpose of this work was to reveal pathological electrophysiological changes in patients with different cardiological diseases by means of magnetocardiographic (MCG) mapping. MCG mapping was performed with a 7-channel magnetocardiograph without a magnetically shielded room. We divided the 159 subjects studied into seven groups: 44 healthy controls, 42 patients with coronary artery disease (CAD), 11 patients affected with myocardiac infarction (MI), 11 with hypertension (HT), 14 with silent ischemia (SI), 13 with heart failure (HF), 14 with fibrillation (FB), and 10 patients after stunning of coronary arteries (ST). All patients were examined using a standard 12-lead electrocardiogram (ECG), biochemical analyses, and loading tests (bicycle-ergometry); some were also studied by holter monitoring, echocardiography, electrophysiological test, and coronary angiography. Morphological and correlation analyses of MCG maps were performed. Moreover, a number of quantitative MCG indices, which reflect the distribution of the excitation in the heart, were proposed. We observed that some indices demonstrated efficiency in recognition of pathologic activity for 5 diseases: CAD, MI, HT, HF, SI and FB.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"111"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multimodal imaging of somatosensory evoked cortical activity. 体感觉诱发皮层活动的多模态成像。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

C Ramon, J Haueisen, T Richards, K Maravilla

引用次数: 0

Advanced electronics for the CTF MEG system. CTF MEG系统的先进电子设备。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

J McCubbin, J Vrba, P Spear, D McKenzie, R Willis, R Loewen, S E Robinson, A A Fife

{"title":"Advanced electronics for the CTF MEG system.","authors":"J McCubbin, J Vrba, P Spear, D McKenzie, R Willis, R Loewen, S E Robinson, A A Fife","doi":"","DOIUrl":"","url":null,"abstract":"Development of the CTF MEG system has been advanced with the introduction of a computer processing cluster between the data acquisition electronics and the host computer. The advent of fast processors, memory, and network interfaces has made this innovation feasible for large data streams at high sampling rates. We have implemented tasks including anti-alias filter, sample rate decimation, higher gradient balancing, crosstalk correction, and optional filters with a cluster consisting of 4 dual Intel Xeon processors operating on up to 275 channel MEG systems at 12 kHz sample rate. The architecture is expandable with additional processors to implement advanced processing tasks which may include e.g., continuous head localization/motion correction, optional display filters, coherence calculations, or real time synthetic channels (via beamformer). We also describe an electronics configuration upgrade to provide operator console access to the peripheral interface features such as analog signal and trigger I/O. This allows remote location of the acoustically noisy electronics cabinet and fitting of the cabinet with doors for improved EMI shielding. Finally, we present the latest performance results available for the CTF 275 channel MEG system including an unshielded SEF (median nerve electrical stimulation) measurement enhanced by application of an adaptive beamformer technique (SAM) which allows recognition of the nominal 20-ms response in the unaveraged signal.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"69"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24895648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Localization of interictal spikes using SAM(g2) and dipole fit. 利用SAM（g2）和偶极子拟合定位间隙尖峰。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

S E Robinson, S S Nagarajan, M Mantle, V Gibbons, H Kirsch

{"title":"Localization of interictal spikes using SAM(g2) and dipole fit.","authors":"S E Robinson, S S Nagarajan, M Mantle, V Gibbons, H Kirsch","doi":"","DOIUrl":"","url":null,"abstract":"SAM(g2) is an automated analysis that transforms the MEG data into a functional image of spike-like activity, giving the source waveforms for those locations. Since the source waveforms estimated by SAM have higher signal-to-noise ratio (SNR) than does the raw MEG data, it is possible to automatically mark the location and timing of each spike for comparisons with dipole fit procedures. Both SAM(g2) and equivalent current dipole (ECD) fits were used to analyze MEG interictal spike recordings in 10 patients with cortical dysplasias and medial temporal lobe epilepsy. The ECD fit locations obtained by manual spike classification and latency marking were compared with those found by automated SAM(g2) procedures. When the SNR of interictal activity was high (compared to the background) with a clear single focus, there was excellent agreement between the ECD cluster location and the SAM(g2) maximum. However, when the SNR of spikes was low, manual single ECD location scatter was larger than SAM(g2) reconstructions. When multiple independent interictal spike loci were present, there was some disagreement between SAM(g2) and ECD scatter in the cases of low SNR spikes. When SAM(g2) indicated multiple coupled spike loci, the residual variance for the dipole fit was high and its scatter unacceptably large--even for multiple dipole models. This study demonstrates that SAM(g2) is equivalent to ECD fit for localizing interictal spikes when there is a single locus and good SNR. Further studies are required to validate cases in which there are multiple spike loci or poor SNR.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"74"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4041981/pdf/nihms-23495.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25185830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spatiotemporal brain activity in mental rotation. 心理旋转中的时空大脑活动。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

H Kawamichi, Y Kikuchi, S Ueno, S Yoshizawa

{"title":"Spatiotemporal brain activity in mental rotation.","authors":"H Kawamichi, Y Kikuchi, S Ueno, S Yoshizawa","doi":"","DOIUrl":"","url":null,"abstract":"There are many higher-order cognitive processes whose neural mechanisms are hard to study by using nonhuman primates. The mental rotation task is one of the best studied of these. We investigated the spatiotemporal brain activity underlying mental rotation of different kinds of stimuli by measuring the magnetoencephalogram of subjects performing two kinds of mental rotation tasks. Visual stimuli in one experiment consisted of hand shapes presented at various orientations, and those in the other consisted of a set of alphabetic characters and their mirror images presented at various orientations. All stimuli were presented in the left visual field. Activity associated with visual stimulus processing was estimated in the lateral occipital lobe, basal occipitotemporal area, and inferior temporal gyrus. Activities related to higher visual processing were differed between the two kinds of stimuli we used. For the hand shape experiment, we found right inferior parietal lobule activity at 200-300 ms after the stimulus presentation. For the alphabetic characters, activity was found in the left superior temporal region at about 300 ms. Furthermore, activity related to mental stimulation in the inferior parietal lobule and premotor area were seen in the both experiments. In the experiments with hands, the premotor activity showed left-hemispheric dominance. However, in the experiments with alphabetic characters, the laterality of the premotor activity did not show left-hemispheric dominance. We inferred this difference was influenced by the subjects' familiarity with the mental rotation of visual stimuli.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"66"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Forward solution ambiguity for fMEG model. fMEG模型的正向解模糊。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

J Vrba, S E Robinson, J McCubbin

{"title":"Forward solution ambiguity for fMEG model.","authors":"J Vrba, S E Robinson, J McCubbin","doi":"","DOIUrl":"","url":null,"abstract":"Accurate knowledge of the electromagnetic model of the fetal brain is required for quantitative fetal MEG (fMEG) signal analysis. The model is defined by the fetal head position, assuming that volume currents are confined to it. Head position can be located by 3D ultrasound. Since the ultrasound is presently not integrated with fMEG, there is a potential for fetal head motion when the mother moves between the two instruments. To interpret the fMEG data without accurate information about the fetal head position, a model search must be undertaken to localize not only the fMEG source within the fetal head, but also the fetal head within the maternal abdomen. Such model search results in multiple solutions with different source amplitudes, but with roughly the same fit errors [Vrba, 2004]. We show that this behaviour is caused by the forward solution ambiguity. For a given measurement, there is a large region within the maternal abdomen within which all fetal head centers produce reasonably good explanation of the observed signal. The source positions within these different fetal heads are different, but the resulting signals are indistinguishable in the presence of even a small noise. Similar ambiguity also exists in adult MEG, where it usually does not pose a problem because the head position is well known.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"87"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0