The magnetic and electric fields agree with intracranial localizations of somatosensory cortex

Sutherling, William W.; Crandall, Paul H.; Darcey, Terrance M.; Becker, Donald P.; Lévesque, Michel; Barth, Daniel S.

doi:10.1212/wnl.38.11.1705

Cited by 195 publications

(64 citation statements)

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“…This study demonstrates that MEG recordings modeled as a single ECD can map the primary somatosensory region with high spatial resolution and that the number of distinguishable somatosensory sites is substantially greater than has been previously reported for humans (6,(10)(11)(12)(13)(14)(15)(16)(17)(18). Closely spaced tactile sites on the skin surface can map to distinguishable separate cortical areas on the MRI overlays by using a single FIG.…”

Section: Discussionmentioning

confidence: 65%

“…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%

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confidence: 99%

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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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Section: Discussionmentioning

confidence: 65%

mentioning

confidence: 99%

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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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“…6,18,26,29,33,37,50,55 The authors of several studies on mapping the sensorimotor cortex have reported that despite having a common general organization, variations in the somatotopy are frequently found. 2,6,7,18,26,29,33,37,38,52,53,55 They suggest that Penfield's homunculus be used as a simplified teaching tool but not as an accurate map (Fig. 9).…”

Section: Neural Featuresmentioning

confidence: 99%

“…9). 2,18,38,52,53 Two groups have reported sensorimotor function outside the central lobe. 5,55 These studies suggested that the primary motor cortex may extend beyond the anterior edge of the precentral gyrus.…”

Section: Neural Featuresmentioning

confidence: 99%

Microsurgical anatomy of the central lobe

Frigeri

Paglioli

Oliveira

et al. 2015

JNS

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T he central lobe, composed of the pre-and postcentral gyri and the paracentral lobule is one of the most eloquent areas of the brain, and it corresponds to the sensorimotor cortex. This morphological unit, together with the functional interaction between motricity and sensitivity, justifies the characterization of these gyri as a single lobe. 45There have been several studies of gyral and sulcal anatomy, craniometrics, and vascular features that included this area. 1,4,10,11,17,19,[21][22][23][24]28,36,[39][40][41][43][44][45][46]51,54,56,57 However, important details are still lacking. The aim of the present study is to define the neural features, craniometric relationships, arterial supply, and venous drainage of the central lobe. MethodsThe central lobe was examined under magnifications of ×3 to ×40 in 20 formalin-fixed cadaveric hemispheres in which the arteries were perfused with red and the veins with blue silicone. The frontal and parietal bones were removed while preserving the coronal suture to study its relationship with the anterior and posterior limits of the precentral gyrus. The arachnoid membrane was removed from the gyral surfaces and variations in the sulci and gyri were examined. The inclination of the central sulcus and coronal suture compared with their coronal planes was measured. The distances between the coronal suture and the anterior and posterior limits of the precentral gyrus abbreviatioNs ACA = anterior cerebral artery; AVM = arteriovenous malformation; MCA = middle cerebral artery. subMitted February 11, 2014. accepted November 11, 2014. iNclude wheN citiNg Published online January 2, 2015; DOI: 10.3171/2014.11.JNS14315. disclosure Financial support was provided by the University of Florida Foundation. The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. obJect The central lobe consists of the pre- and postcentral gyri on the lateral surface and the paracentral lobule on the medial surface and corresponds to the sensorimotor cortex. The objective of the present study was to define the neural features, craniometric relationships, arterial supply, and venous drainage of the central lobe. Methods Cadaveric hemispheres dissected using microsurgical techniques provided the material for this study. results The coronal suture is closer to the precentral gyrus and central sulcus at its lower rather than at its upper end, but they are closest at a point near where the superior temporal line crosses the coronal suture. The arterial supply of the lower two-thirds of the lateral surface of the central lobe was from the central, precentral, and anterior parietal branches that arose predominantly from the superior trunk of the middle cerebral artery. The medial surface and the superior third of the lateral surface were supplied by the posterior interior frontal, paracentral, and superior parietal branches of the pericallosal and callosomarginal arteries. The venous drainage of the superior two-thirds of the late...

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Comparison of primary motor cortex localization using functional magnetic resonance imaging and magnetoencephalography

1996

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The primary goal of the study was to compare estimates of motor cortex localization from functional magnetic resonance imaging (FMRI) and magnetoencephalography (MEG). Thirteen normal volunteers were studied using both methods. FMRI was performed on a clinical 1.5 T system using gradient-echo acquisitions and basic t-test processing. MEG primary motor field was characterized by a single dipole model. Comparisons between the location of the best-fitting MEG dipole and the FMRI activation results were made using both fixed regions-of-interest weighted averaging and clustering analysis to reduce the observed FMRI activations to a single representative location. Both FMRI and MEG identified expected anatomic regions of primary motor activity and there was overall agreement to within 10 mm between these two functional imaging modalities. Given the observed agreement between these two techniques, it does not appear that the proposed artifactual mechanisms of local bulk motions or large-vessel sensitivity will seriously preclude the clinical utility of FMRI for preoperative localization of sensorimotor cortex.

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The magnetic and electric fields agree with intracranial localizations of somatosensory cortex

Cited by 195 publications

References 0 publications

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

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

Microsurgical anatomy of the central lobe

Comparison of primary motor cortex localization using functional magnetic resonance imaging and magnetoencephalography

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