Detecting functional asymmetries through the dipole moment of magnetoencephalography

Tsutada, Tsuyoshi; Ikeda, Hitoshi; Tsuyuguchi, Naohiro; Hattori, Hideji; Shimogawara, Masahiro; Shimada, Hiroyuki; Miki, Takami

doi:10.1016/s0022-510x(02)00076-x

Cited by 10 publications

(7 citation statements)

References 9 publications

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“…Recently, some clinical studies have been conducted to examine the usefulness of dipoles and it has been disclosed that dipole moment is a helpful parameter to assess the severity of the sensory disorder in cases of cervical spondylotic myelopathy [6]. Assessing somatosensory evoked magnetic field and single photon emission computed tomography, Tsutada et al [7] showed that the dipole moment provided a reliable quantitative index of cortical response to somatosensory stimulus by median nerve stimulation, and the moment measurement thus holds promise as a clinical tool for direct quantification of cortical response. On the basis of the principles of MEG technology, the following conditions were identified as being ideal for assessing the intensity of dipoles as absolute values determined by the least-square method in which a spherically symmetrical head model is used: dipole present near the surface with an orientation tangential to the surface; presence of a high GOF.…”

Section: Discussionmentioning

confidence: 99%

“…Magnetoencephalography (MEG) has an advantage in both time and spatial resolution because of its magnetic measurement of electric activity and magnetic penetrability in the human body. The dipole moment is one of the parameters that have been shown to be useful in somatosensory evoked magnetic field [6,7], though it has not been applied to investigations of the primary visual cortex response (V1 response). In this study, we focused on the effect of ocular dominance on latency and magnitude of dipole moment of visual evoked magnetic field (VEF).…”

Section: Introductionmentioning

confidence: 99%

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Ocular dominance affects magnitude of dipole moment: an MEG study

Shima

Hasegawa²,

Tachibana

et al. 2010

NeuroReport

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O c u l a r d o m i n a n c e a f f e c t s m a g n i t u d e o f d i p o l e m o m e n t : a n M E G s t u d y H i r o s h i S h i m a 1 , 2 , M i t s u h i r o H a s e g a w a 1 , 4 O s a m u Ta c h i b a n a 1 , 5 , M o t o h i r o N o m u r a 1 , 2 , J u n k o h Ya m a s h i t a 1 , 6 Yu z o O z a k i 3 , J u n K a w a i 3 , M a s a n o r i H i g u c h i 3 , H i s a s h i K a d o 3 D e p a r t m e n t o f N e u r o s u r g e r y, G r a d u a t e S c h o o l o f M e d i c a l S c i e n c e , K a n a z a wa U n i ve r s i t y, K a n a z a wa , J a p a n 1 D e p a r t m e n t o f N e u r o s u r g e r y, Yo k o h a m a S a k a e K yo s a i H o s p i t a l , Yo k o h a m a , J a p a n 2 3 A p p l i e d E l e c t r o n i c s L a b o r a t o r y, K a n a z a wa I n s t i t u t e o f Te c h n o l o g y, K a n a z a wa , J a p a n 2 4 D e p a r t m e n t o f N e u r o s u r g e r y, F u j i t a H e a l t h U n i ve r s i t y, To yo a k e , J a p a n 5 D e p a r t m e n t o f N e u r o s u r g e r y, K a n a z a wa M e d i c a l U n i ve r s i t y, I s h i k a wa , J a p a n 6 D e p a r t m e n t o f N e u r o s u r g e r y, J u j o R e h a b i l i t a t i o n H o s p i t a l , K yo t o , J a p a n D e p a r t m e n t o f N e u r o s u r g e r y, Yo k o h a m a S a k a e K yo s a i H o s p i t a l 1 3 2 K a t s u r a -c h o , S a k a e -k u , Yo k o h a m a , 2 4 7 -8 5 8 1 J a p a n 3 P h o n e : + 8 1 -4 5 -8 9 1 -2 1 7 1 , F a x : + 8 1 -4 5 -8 9 5 -8 3 5 1 e -m a i l : i s l a n d @ v e s t a . o c n . n e . j p T h i s wo r k wa s s u p p o r t e d b y a g r a n t -i n -a i d f o r e x p l o r a t o r y r e s e a r c h f r o m t h e M i n i s t r y o f E d u c a t i o n , C u l t u r e , S p o r t s , S c i e n c e a n d T e c h n o l o g y , J a p a n ( N o . 1 6 6 5 9 3 8 3 ) .T h e m a i n b o d y t e x t o f t h i s p a p e r i s 1 1 , 7 9 1 c h a r a c t e r s l o n g .

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ocular dominance affects magnitude of dipole moment: an MEG study

Shima

Hasegawa²,

Tachibana

et al. 2010

NeuroReport

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“…At each major peak, representing a cortical area of interest, six dipole characteristics (3 location, 2 orientation and strength) were determined. In particular, dipole strength was earlier described as a reliable quantitative index of cortical response to a somatosensory stimulus (Tsutada et al 2002).…”

Section: Ecd Characteristicsmentioning

confidence: 99%

Sensory Handedness is not Reflected in Cortical Responses After Basic Nerve Stimulation: A MEG Study

et al. 2011

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Motor dominance is well established, but sensory dominance is much less clear. We therefore studied the cortical evoked magnetic fields using magnetoencephalography (MEG) in a group of 20 healthy right handed subjects in order to examine whether standard electrical stimulation of the median and ulnar nerve demonstrated sensory lateralization. The global field power (GFP) curves, as an indication of cortical activation, did not depict sensory lateralization to the dominant left hemisphere. Comparison of the M20, M30, and M70 peak latencies and GFP values exhibited no statistical differences between the hemispheres, indicating no sensory hemispherical dominance at these latencies for each nerve. Field maps at these latencies presented a first and second polarity reversal for both median and ulnar stimulation. Spatial dipole position parameters did not reveal statistical left-right differences at the M20, M30 and M70 peaks for both nerves. Neither did the dipolar strengths at M20, M30 and M70 show a statistical left-right difference for both nerves. Finally, the Laterality Indices of the M20, M30 and M70 strengths did not indicate complete lateralization to one of the hemispheres. After electrical median and ulnar nerve stimulation no evidence was found for sensory hand dominance in brain responses of either hand, as measured by MEG. The results can provide a new assessment of patients with sensory dysfunctions or perceptual distortion when sensory dominance occurs way beyond the estimated norm.

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“…The genotype–phenotype correlation studies used at present include a detailed physical (and neurological) examination, biochemical analysis, neuropsychological and behavioral testing, combined with electroencephalogram (EEG), computerized tomography (CT)‐ or magnetic resonance imaging (MRI) scanning and single‐photo emission computed tomography‐imaging (SPECT) of the brain. Future genotype–phenotype correlation studies could be made more informative by the inclusion of neurophysiological tests for dynamic brain functions, such as magnetoencephalography (MEG) (94) and functional MRI scanning (fMRI) (95). Investigation of the function of the hippocampus, as thought to be the processor of memory storage, could provide additional insight in the cognitive network and in the way this process can be disturbed in patients with MR.…”

Section: Future Directionsmentioning

confidence: 99%

X‐linked mental retardation: vanishing boundaries between non‐specific (MRX) and syndromic (MRXS) forms

2002

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This review covers the history and nosology of X-linked mental retardation (XLMR) in which the following, largely clinically based, subclassification was used: fragile X syndrome (FRAXA), syndromic forms (MRXS) and non-specific forms (MRX). After the discovery of the FMR2 gene at the FRAXE site, 10 MRX genes have been identified in the last 6 years. A short description is given of the strategies used to identify the genes that cause mental retardation (MR). Furthermore, their potential functions and the association with MR will be discussed. It is emphasized that mutations in several of these MR genes can result in non-specific, as well as in syndromic forms of XLMR. Present findings stress the importance of accurate clinical evaluation. Most considerably, genotype-phenotype correlation studies of affected individuals in XLMR families with MRX gene mutations are necessary to define the criteria of MRX vs MRXS subclassification.

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Detecting functional asymmetries through the dipole moment of magnetoencephalography

Cited by 10 publications

References 9 publications

Ocular dominance affects magnitude of dipole moment: an MEG study

Ocular dominance affects magnitude of dipole moment: an MEG study

Sensory Handedness is not Reflected in Cortical Responses After Basic Nerve Stimulation: A MEG Study

X‐linked mental retardation: vanishing boundaries between non‐specific (MRX) and syndromic (MRXS) forms

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