Anatomical localization revealed by MEG recordings of the human somatosensory system

Suk, Jin; Ribary, Urs; Cappell, Joshua; Yamamoto, Tomoya; Llinás, Rodolfó R.

doi:10.1016/0013-4694(91)90032-y

Cited by 113 publications

(32 citation statements)

References 16 publications

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“…The study included recording and localization of tactileevoked magnetic fields for all five fingers in four subjects and the thumb, index, and little fingers in the remaining five. Superposition of equivalent current dipole sources onto MRI images has shown that these sources lie in area 3b of sensory cortex, located on the anterior bank of the postcentral gyrus (14). Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Magnetoencephalography (MEG) is a noninvasive functional brain imaging technique that provides information regarding neuronal activity with high temporal and spatial resolution (10)(11)(12)(13)(14). Initial studies using MEG (10,12,14) demonstrated the somatotopy of the human somatosensory cortex, and present-day technology allows such functional maps to be defined with millimeter precision (14).…”

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confidence: 99%

“…Initial studies using MEG (10,12,14) demonstrated the somatotopy of the human somatosensory cortex, and present-day technology allows such functional maps to be defined with millimeter precision (14). We have been investigating the detailed functional organization of the hand area in normal adult humans and in patients with a variety of congenital and traumatic hand abnormalities.…”

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confidence: 99%

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Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography.

Mogilner

Grossman

Ribary

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

225

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Microelectrode recordings in adult mammals have clearly demonstrated that somatosensory cortical maps reorganize following peripheral nerve injuries and functional modifications; however, such reorganization has never been directly demonstrated in humans. Using magnetoencephalography, we have been able to demonstrate the somatotopic organization of the hand area in normal humans with high spatial precision. Somatosensory cortical plasticity was detected in two adults who were studied before and after surgical separation of webbed fingers (syndactyly). The presurgical maps displayed shrunken and nonsomatotopic hand representations. Within weeks following surgery, cortical reorganization occurring over distances of 3-9 mm was evident, correlating with the new functional status of their separated digits. In contrast, no modification of the somatosensory map was observed months following transfer of a neurovascular skin island flap for sensory reconstruction of the thumb in two subjects in whom sensory transfer failed to occur.Understanding the presence, degree, and functional correlations for human cortical plasticity is of major significance for fundamental neuroscience as well as a potential aid in the diagnosis and rehabilitation of patients with peripheral and central nervous system injuries. That cortical maps can undergo reorganization in adult mammals has been demonstrated following a variety of peripheral sensory alterations including nerve transection (1-3), digital amputation (4,5) and syndactyly (6), and behavioral modification (7,8). Direct neurophysiological evidence for human somatosensory cortical plasticity, however, has never been demonstrated (9).Magnetoencephalography (MEG) is a noninvasive functional brain imaging technique that provides information regarding neuronal activity with high temporal and spatial resolution (10-14). Initial studies using MEG (10,12,14) demonstrated the somatotopy of the human somatosensory cortex, and present-day technology allows such functional maps to be defined with millimeter precision (14). We have been investigating the detailed functional organization of the hand area in normal adult humans and in patients with a variety of congenital and traumatic hand abnormalities. We report here evidence of adult human cortical plasticity, occurring over a time period of weeks to months following surgical correction of congenital syndactyly in two adult males. METHODSA 14-and a 37-channel biomagnetic recording system (Biomagnetic Technologies, San Diego) were used. The orientation of the subject's head in relation to the MEG recording probes was calculated using the sensor position indicator (SPI), a system of transmitters located on the dewars and receivers. affixed to a headband on the patient's head. Sensor locations were expressed using a head-based coordinate system whose origin was defined as the point of perpendicular intersection of the line extending from the nasion and the line connecting the penauricular points. The x, y, and z axes were the lines from t...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography.

Mogilner

Grossman

Ribary

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

225

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“…However, a variety of neuroimaging tools have been developed which may noninvasively study human mental functions. The human somatosensory cortex has been partially mapped using positron emission tomography (PET) (6), electroencephalography (EEG) (7-9), and magnetoencephalography (MEG) (10)(11)(12)(13)(14)(15)(16)(17)(18) METHODS Somatosensory stimulus-evoked magnetic brain activity generated by the left and right cortex in two neurologically normal undergraduate male subjects was recorded inside of a magnetically shielded room by using a Magnes 37-channel biomagnetometer (Biomagnetic Technologies, San Diego). The neuromagnetic field pattern was recorded over a 144-mm-diameter circular area above the parietotemporal cortex.…”

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confidence: 99%

Noninvasive somatosensory homunculus mapping in humans by using a large-array biomagnetometer.

Yang

Gallen²,

Schwartz³

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

121

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To validate the feasibility of precise noninvasive functional mapping in humans, a large-array biomagnetometer was used to map the somatosensory cortical locations corresponding to numerous distinct tactile sites on the fmgers, hand, arm, and face in different subjects. Source localizations were calculated by using a single equivalent current dipole (ECD) model. Dipole localizations were transposed upon the corresponding subject's magnetic resonance image (MRI) to resolve the anatomic locus of the individual dipoles within a given subject. Biomagnetic measurements demonstrated that (i) there were distinct separations between the ECD locations representing discrete sites on the face and hand; (u) the ECD localizations from facial sites clustered in a region inferior to ECD localizations from hand and digit sites; and (iii) there was clear spatial resolution of ECD locations representing closely spaced tactile sites on the hand and face. The ability of magnetoencephalography (MEG) to provide high-resolution spatial maps of the somatosensory system noninvasively in humans should make MEG a useful tool to defme the normal or pathological organization of the human somatosensory system and should provide an approach to the rapid detection of neuroplasticity.Functional mapping of the human somatosensory system has commonly used invasive surgical techniques which involve electrical stimulation of the brain (1), direct recordings of evoked potentials and electrical stimulation (2), somatosensory evoked responses (SERs) recorded on electrocorticography (ECoG) (3), or cortical surface recordings of somatosensory evoked potentials (SEP) during surgery (4, 5). The invasiveness of these approaches has limited the number of patients which may be studied and the types of questions which may be addressed. However, a variety of neuroimaging tools have been developed which may noninvasively study human mental functions. The human somatosensory cortex has been partially mapped using positron emission tomography (PET) (6), electroencephalography (EEG) (7-9), and magnetoencephalography (MEG) (10)(11)(12)(13)(14)(15)(16)(17)(18) METHODS Somatosensory stimulus-evoked magnetic brain activity generated by the left and right cortex in two neurologically normal undergraduate male subjects was recorded inside of a magnetically shielded room by using a Magnes 37-channel biomagnetometer (Biomagnetic Technologies, San Diego). The neuromagnetic field pattern was recorded over a 144-mm-diameter circular area above the parietotemporal cortex. Intrinsic noise in each channel was <10 ff/Hzl/2 in all but one channel.The biomagnetometer was placed over the contralateral hemisphere relative to the side being stimulated. Subjects were instructed to hold extremely still, and to count silently the number of stimuli.Tactile stimulators provided skin surface stimulation. The stimulators, which were circular rubber bladders of 1 cm diameter encased within a plastic outer shell, expanded with air during each time period corresponding to a single stim...

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“…This program was developed using data obtained at the Center for Neuromagnetism in the Department of Neuroscience and Physiology at the New York University School of Medicine. Studies in this laboratory have addressed spontaneous and evoked brain activity under both physiological (12)(13)(14)(15)(16) and pathophysiological [17][18][19] conditions. Authors were participating in the development of new methods of data analysis [20][21][22], included in the MEGMRIAn software and verified on the experimental data.…”

Section: Introductionmentioning

confidence: 99%

Новая методология анализа и представления функциональной структуры мозга человека: MEGMRIAn

Ustinin¹

2014

Math.Biol.Bioinf.

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Abstract. The present software was developed to implement a highly spatiotemporal resolved functional tomography (1mm/1msec), capable of addressing spontaneous and evoked activity at any point in the human brain. Presently the methodology is implemented for the magnetic encephalography data. Data analysis results are embedded into a magnetic resonance image of the head. This image is also used as the head model to calculate the magnetic fields of the equivalent current dipoles, while probe positions correspond to real device coordinates. This methodology allows the superposition of the functional frequency patterns to be represented together with magnetic resonance images. The software computational speed makes it possible to implement the whole data acquisition and imaging cycle fast enough to allow optimal protocol choice in data processing.

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Anatomical localization revealed by MEG recordings of the human somatosensory system

Cited by 113 publications

References 16 publications

Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography.

Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography.

Noninvasive somatosensory homunculus mapping in humans by using a large-array biomagnetometer.

Новая методология анализа и представления функциональной структуры мозга человека: MEGMRIAn

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