TY - JOUR
T1 - Neuromagnetic evidence of pre- and post-central cortical sources of somatosensory evoked responses
AU - Kawamura, Tsuyoshi
AU - Nakasato, Nobukazu
AU - Seki, Kaoru
AU - Kanno, Akitake
AU - Fujita, Satoshi
AU - Fujiwara, Satoru
AU - Yoshimoto, Takashi
PY - 1996
Y1 - 1996
N2 - Somatosensory evoked magnetic fields (SEFs), corresponding with electrical-median nerve stimulation, were measured using an MRI-linked, whole-head MEG system. In total 184 hemispheres, SEFs were measured, involving 22 normal volunteers and 70 patients with intracranial lesions. The first SEF peak appeared 20.2 ± 1.5 msec (mean ± S.D.) after stimulation. The first peak was followed by a second and third peak, 7.7 ± 3.2 msec and 14.6 ± 5.4 msec respectively after the first. Corresponding isofield maps suggested a single current dipole oriented in the anterior direction for the first peak, posterior for the second and either anterior or posterior for the third. Using a spherical model and a single current dipole source, the localization of each peak was estimated and superimposed on individually determined MRI images. On a grand average basis, the first-peak dipole was localized on the posterior surface of the central sulcus, 'area 3b'. The second-peak dipole was localized 3.7 mm medial (P < 0.001) and 2.0 mm superior ( < 0.001) to the first-peak dipole, on the anterior wall of the central sulcus, 'area 4'. This study with a large number of subjects was able to statistically distinguish two adjacent cortical sources, located on opposite walls of the central sulcus, and within a few millimeters of each other.
AB - Somatosensory evoked magnetic fields (SEFs), corresponding with electrical-median nerve stimulation, were measured using an MRI-linked, whole-head MEG system. In total 184 hemispheres, SEFs were measured, involving 22 normal volunteers and 70 patients with intracranial lesions. The first SEF peak appeared 20.2 ± 1.5 msec (mean ± S.D.) after stimulation. The first peak was followed by a second and third peak, 7.7 ± 3.2 msec and 14.6 ± 5.4 msec respectively after the first. Corresponding isofield maps suggested a single current dipole oriented in the anterior direction for the first peak, posterior for the second and either anterior or posterior for the third. Using a spherical model and a single current dipole source, the localization of each peak was estimated and superimposed on individually determined MRI images. On a grand average basis, the first-peak dipole was localized on the posterior surface of the central sulcus, 'area 3b'. The second-peak dipole was localized 3.7 mm medial (P < 0.001) and 2.0 mm superior ( < 0.001) to the first-peak dipole, on the anterior wall of the central sulcus, 'area 4'. This study with a large number of subjects was able to statistically distinguish two adjacent cortical sources, located on opposite walls of the central sulcus, and within a few millimeters of each other.
KW - Dipole model
KW - Functional anatomy
KW - Magnetic resonance imaging
KW - Somatosensory cortex
KW - Somatosensory evoked response
KW - Whole-head magnetometry
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U2 - 10.1016/0168-5597(95)00217-0
DO - 10.1016/0168-5597(95)00217-0
M3 - Article
C2 - 8964262
AN - SCOPUS:0030041514
SN - 0168-5597
VL - 100
SP - 44
EP - 50
JO - Electroencephalography and Clinical Neurophysiology - Evoked Potentials
JF - Electroencephalography and Clinical Neurophysiology - Evoked Potentials
IS - 1
ER -