Neurology & clinical neurophysiology : NCN最新文献_第4页

Auditory evoked field responses in the left hemisphere to morphosyntactic violations in Korean sentence. 朝鲜语句子中形态句法违反的左半球听觉诱发场反应。

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

H Kwon, J M Kim, Y H Lee, K Kim, Y K Park, K Nam, S Kuriki

引用次数: 0

Auditory cortex responses to the transition from monophonic to pseudo-stereo sound. 听觉皮层对从单声道到伪立体声过渡的反应。

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

B Ross, At T Herdman, A Wollbrink, C Pantev

引用次数: 0

Effect of word familiarity on visually evoked magnetic fields. 词汇熟悉度对视觉诱发磁场的影响。

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

N Harada, S Iwaki, S Nakagawa, M Yamaguchi, M Tonoike

{"title":"Effect of word familiarity on visually evoked magnetic fields.","authors":"N Harada, S Iwaki, S Nakagawa, M Yamaguchi, M Tonoike","doi":"","DOIUrl":"","url":null,"abstract":"This study investigated the effect of word familiarity of visual stimuli on the word recognizing function of the human brain. Word familiarity is an index of the relative ease of word perception, and is characterized by facilitation and accuracy on word recognition. We studied the effect of word familiarity, using \"Hiragana\" (phonetic characters in Japanese orthography) characters as visual stimuli, on the elicitation of visually evoked magnetic fields with a word-naming task. The words were selected from a database of lexical properties of Japanese. The four \"Hiragana\" characters used were grouped and presented in 4 classes of degree of familiarity. The three components were observed in averaged waveforms of the root mean square (RMS) value on latencies at about 100 ms, 150 ms and 220 ms. The RMS value of the 220 ms component showed a significant positive correlation (F=(3/36); 5.501; p=0.035) with the value of familiarity. ECDs of the 220 ms component were observed in the intraparietal sulcus (IPS). Increments in the RMS value of the 220 ms component, which might reflect ideographical word recognition, retrieving \"as a whole\" were enhanced with increments of the value of familiarity. The interaction of characters, which increased with the value of familiarity, might function \"as a large symbol\"; and enhance a \"pop-out\" function with an escaping character inhibiting other characters and enhancing the segmentation of the character (as a figure) from the ground.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"34"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184685","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

Effect of sodium valproate on neuromagnetic responses to chromatic flicker: implication for photosensitivity. 丙戊酸钠对色光闪烁神经磁反应的影响:对光敏性的影响。

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

K Watanabe, R Sayres, S Shimojo, T Imada, K Nihei

{"title":"Effect of sodium valproate on neuromagnetic responses to chromatic flicker: implication for photosensitivity.","authors":"K Watanabe, R Sayres, S Shimojo, T Imada, K Nihei","doi":"","DOIUrl":"","url":null,"abstract":"The effect of oral administration of sodium valproate in normal subjects was evaluated using whole-scalp magnetoencephalography, with results compared to the effect of sodium valproate in photosensitive children. Neuromagnetic responses to 10 Hz equiluminant red-green and red-blue flicker were measured before and after 5 days of sodium valproate administration. For the red-green flicker, relative power spectra at the stimulus frequency (10 Hz) were attenuated with medication in most brain regions. However, for the red-blue flicker, the 10-Hz power in the occipital region was enhanced with medication, while it was reduced in other regions. These results qualitatively resembled those in photosensitive children. The present findings suggest that (1) combinational chromatic sensitivity can be a critical factor for cortical excitability, that (2) the effect of sodium valproate is qualitatively similar in normal and photosensitive subjects, and that (3) the effect of sodium valproate on cortical excitability is not simply to suppress the stimulus-synchronized occipital activity, but rather to inhibit the spread of cortical activity from the occipital region to other regions.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"61"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184686","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

Spatial distribution of cardiac magnetic vector fields acquired from 3120 SQUID positions. 从3120个SQUID位置获取心脏磁场的空间分布。

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

U Steinhoff, A Schnabel, M Burghoff, T Freibier, F Thiel, H Koch, L Trahms

{"title":"Spatial distribution of cardiac magnetic vector fields acquired from 3120 SQUID positions.","authors":"U Steinhoff, A Schnabel, M Burghoff, T Freibier, F Thiel, H Koch, L Trahms","doi":"","DOIUrl":"","url":null,"abstract":"An extended measurement of the magnetic vector field of the human heart is presented. It is acquired by sequential recordings, shifting a 16 SQUID vector magnetometer across 195 positions over a healthy subject's thorax. The magnetocardiographic (MCG) signals were synchronized using a simultaneously measured ECG channel. The registration of the field extends over a volume of 1000 mm x 600 mm x 420 mm sampled at 3120 SQUID positions. We present diagrams of the vector amplitude of selected points in 6 planes at increasing distances from the frontal thorax. Each plane contains 76 vector points. Additionally, we measured the vector field at 126 points lateral to the chest. At the edge points of the measurement volume, the absolute value of the magnetic vector signal amplitude exceeds 0.3 pT in all measurement points. The dataset provides an excellent base to study dedicated MCG detection or rejection methods. Examples where rejection of the heart signal is necessary are magnetoencephalography, magnetoneurography and fetal MCG. The knowledge of the spatio-temporal distribution of the magnetic vector field of the heart supports the development and comparison of multi-SQUID systems and will be used to create new MCG interpretation and representation algorithms.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"59"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25185575","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

Cortical oscillations modulated by congruent and incongruent audiovisual stimuli. 由一致和不一致的视听刺激调节的皮质振荡。

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

A T Herdman, T Fujioka, W Chau, B Ross, C Pantev, T W Picton

{"title":"Cortical oscillations modulated by congruent and incongruent audiovisual stimuli.","authors":"A T Herdman, T Fujioka, W Chau, B Ross, C Pantev, T W Picton","doi":"","DOIUrl":"","url":null,"abstract":"Congruent or incongruent grapheme-phoneme stimuli are easily perceived as one or two linguistic objects. The main objective of this study was to investigate the changes in cortical oscillations that reflect the processing of congruent and incongruent audiovisual stimuli. Graphemes were Japanese Hiragana characters for four different vowels (/a/, /o/, /u/, and /i/). They were presented simultaneously with their corresponding phonemes (congruent) or non-corresponding phonemes (incongruent) to native-speaking Japanese participants. Participants' reaction times to the congruent audiovisual stimuli were significantly faster by 57 ms as compared to reaction times to incongruent stimuli. We recorded the brain responses for each condition using a whole-head magnetoencephalograph (MEG). A novel approach to analysing MEG data, called synthetic aperture magnetometry (SAM), was used to identify event-related changes in cortical oscillations involved in audiovisual processing. The SAM contrast between congruent and incongruent responses revealed greater event-related desynchonization (8-16 Hz) bilaterally in the occipital lobes and greater event-related synchronization (4-8 Hz) in the left transverse temporal gyrus. Results from this study further support the concept of interactions between the auditory and visual sensory cortices in multi-sensory processing of audiovisual objects.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"15"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25185582","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

Boston and the history of biomagnetism. 波士顿和生物磁学的历史。

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

David Cohen

引用次数: 0

Optimal sensor distribution for measuring the tangential field components in MCG. 测量MCG中切向场分量的最佳传感器分布。

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

K Kim, Y H Lee, H Kwon, J M Kim, I S Kim, Y K Park

{"title":"Optimal sensor distribution for measuring the tangential field components in MCG.","authors":"K Kim, Y H Lee, H Kwon, J M Kim, I S Kim, Y K Park","doi":"","DOIUrl":"","url":null,"abstract":"We discuss the optimal arrangement of detectors for a 52-channel magnetocardiogram (MCG) system measuring tangential components of the cardiac magnetic fields. Nowadays, most MCG instruments are designed to cover the whole heart area to maximize the information available from the myocardial magnetic field in a simultaneous measurement. In such a system, detectors should be spread over a sufficiently wide area. However, an increased diameter of the cooling dewar will result in more heat-loss and higher production and maintenance costs. Therefore, we reviewed the spatial sampling theory to determine the proper interval between detectors, and we decided on the number of channels to cover the whole heart area. In order to fit the detector array on the cylindrical dewar economically, we removed the detectors at the corners of the square array. Through simulations using the confidence region method, we verified that our design of the detector array is enough to obtain adequate information from the heart. Simulations also suggested that tangential-component MCG measurement can localize deep current dipoles better than normal-component measurement with the same confidence volume; therefore, we conclude that measurement of the tangential component is more suitable to an MCG system than the normal component.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"60"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184977","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

Topographic classification of EEG patterns in Huntington's disease. 亨廷顿氏病脑电图模式的地形分类。

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

R Bellotti, F De Carlo, R Massafra, M de Tommaso, V Sciruicchio

{"title":"Topographic classification of EEG patterns in Huntington's disease.","authors":"R Bellotti, F De Carlo, R Massafra, M de Tommaso, V Sciruicchio","doi":"","DOIUrl":"","url":null,"abstract":"The aim of this study is to perform a topographic classification of electroencephalographic (EEG) patterns in subjects affected by the Huntington's disease (HD). The alpha activity is a discriminating feature for HD, as its amplitude reduction turns out to be a clear mark of the illness. When used as input variable to a supervised neural network, a good classification of pathological patterns and control ones is achieved with high values of sensitivity and specificity. It should be useful to get more insight into the local discriminating capabilities of the alpha rhythm by implementing a neural network approach to classify EEG patterns extracted from groups of channels corresponding to specific regions of the scalp. Receiver operating characteristic (ROC) curve analysis enables one to label each region with the value of the area under the curve, thus providing a local significance for HD classification. A reduction of the area when processing regions of the scalp, with respect to the whole, suggests that all channels provide significant contribution to HD pattern discrimination. These results can be interpreted as an effect of an abnormal subcortical modulation of the alpha rhythm, due to the dysfunctional action of the thalamus on the cortical activities. In a further study, morphometric features of thalamus and basal ganglia, evaluated by MRI, will be matched with the electrophysiological findings.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"37"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184672","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 new SQUID biosusceptometer at Oakland: first year of experience. 奥克兰新的SQUID生物感官计:第一年的经验。

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

E B Fung, R Fischer, Z Pakbaz, R L Fagaly, E Vichinsky, T N Starr, T Ewing, D N Paulson, W V Hassenzahl, P Harmatz

{"title":"The new SQUID biosusceptometer at Oakland: first year of experience.","authors":"E B Fung, R Fischer, Z Pakbaz, R L Fagaly, E Vichinsky, T N Starr, T Ewing, D N Paulson, W V Hassenzahl, P Harmatz","doi":"","DOIUrl":"","url":null,"abstract":"Liver iron measurements using biosusceptometers have been validated on two low-TC SQUID (Superconducting Quantum Interference Device) systems (New York and Hamburg) built in the 1980's. Recently, two new instruments have been installed in Torino, Italy (2001), and Oakland, California (2003). The design of the Oakland system is similar to those in Hamburg and Torino. Improvements were made to adjust for significant environmental noise, moreover, an active electronic noise cancellation, a computer controlled water coupling reference system using a pressure feedback and a faster data acquisition system using software lockin amplifiers have been implemented. All 3 systems (Hamburg, Torino, Oakland) are using the same standardized operational protocol. Presented herein are the data collected from 276 patients measured with the SQUID biosusceptometer at Oakland since installation. The results from 149 patients with beta-thalassemia (beta-Thal, age: 2-66 y), 76 patients with sickle-cell disease (SCD, age: 5-55 y), 35 patients with various rare diseases (RD, age: 2-80 y), and 16 patients with hereditary hemochromatosis (HHC, age: 6-74 y) are reported. The liver iron concentration in the different groups are 222 - 7570 (beta-Thal), 518 - 7918 (SCD), 511 - 6234 (RD), 258 - 2041 (HHC) microg/g-liver (in vivo wet weight). The long-term reproducibility (12 months) in a patient on constant treatment regimen demonstrated a mean liver iron of 1141 +/- 133 microg/g-liver. The new SQUID Ferritometer located on the US West coast will give more patients access to this non-invasive liver iron assessment.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"5"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25184674","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