The somatosensory evoked magnetic fields

Kakigi, Ryusuke; Hoshiyama, Minoru; Shimojo, Makoto; Naka, Daisuke; Yamasaki, Hiroshi; Watanabe, Shoko; Xiang, Jing; Maeda, Kengo; Lam, Khanh; Itomi, Kazuya; Nakamura, Akinori

doi:10.1016/s0301-0082(99)00063-5

Cited by 208 publications

(118 citation statements)

References 133 publications

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“…The mean differences show that the stimulus amplitude differences were not driven by the response of an outlier subject. SI, consistent with other studies of tactile stimulation to the fingers (Forss et al, 1994b;Hoechstetter et al, 2000Hoechstetter et al, , 2001Kakigi et al, 2000;Braun et al, 2002;Druschky et al, 2003;Iguchi et al, 2005). Figure 1 shows representative examples of the location and orientation of the ECD on T1-weighted MRI images.…”

Section: Meg Experiments Features Of Si Evoked Responsessupporting

confidence: 88%

“…Previous studies have shown that somatosensory evoked fields (SEFs) can be well approximated with a small number (typically three, for median nerve stimulation) of serially and simultaneously active ECD sources (Brenner et al, 1978;Hari and Forss, 1999). For tactile stimulation, a primary current source is typically initially observed in SI with later activation having additional contributions from a second source, likely representing SII (Forss et al, 1994b;Hari and Forss, 1999;Hoechstetter et al, 2000Hoechstetter et al, , 2001Kakigi et al, 2000). To isolate the contribution from SI to the SEF, we used the following approach.…”

Section: Meg Experimentsmentioning

confidence: 99%

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Neural Correlates of Tactile Detection: A Combined Magnetoencephalography and Biophysically Based Computational Modeling Study

Jones¹,

Pritchett²,

Stufflebeam³

et al. 2007

J. Neurosci.

150

373

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Previous reports conflict as to the role of primary somatosensory neocortex (SI) in tactile detection. We addressed this question in normal human subjects using whole-head magnetoencephalography (MEG) recording. We found that the evoked signal (0 -175 ms) showed a prominent equivalent current dipole that localized to the anterior bank of the postcentral gyrus, area 3b of SI. The magnitude and timing of peaks in the SI waveform were stimulus amplitude dependent and predicted perception beginning at ϳ70 ms after stimulus. To make a direct and principled connection between the SI waveform and underlying neural dynamics, we developed a biophysically realistic computational SI model that contained excitatory and inhibitory neurons in supragranular and infragranular layers. The SI evoked response was successfully reproduced from the intracellular currents in pyramidal neurons driven by a sequence of lamina-specific excitatory input, consisting of output from the granular layer (ϳ25 ms), exogenous input to the supragranular layers (ϳ70 ms), and a second wave of granular output (ϳ135 ms). The model also predicted that SI correlates of perception reflect stronger and shorter-latency supragranular and late granular drive during perceived trials. These findings strongly support the view that signatures of tactile detection are present in human SI and are mediated by local neural dynamics induced by lamina-specific synaptic drive. Furthermore, our model provides a biophysically realistic solution to the MEG signal and can predict the electrophysiological correlates of human perception.

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Section: Meg Experiments Features Of Si Evoked Responsessupporting

confidence: 88%

Section: Meg Experimentsmentioning

confidence: 99%

Neural Correlates of Tactile Detection: A Combined Magnetoencephalography and Biophysically Based Computational Modeling Study

Jones¹,

Pritchett²,

Stufflebeam³

et al. 2007

J. Neurosci.

150

373

View full text Add to dashboard Cite

show abstract

“…[19,22). If so, then the present SEP findings for patient ED imply that residual activation of primary and/or secondary somatosensory cortex, by touch on the contralesional hand, can be insufficient to generate tactile awareness in an extinction patient.…”

Section: Discussionmentioning

confidence: 75%

“…Both components were elicited at electrodes over somatosensory areas contralateral to the stimulated hand, being strongly lateralised. The P45 is most likely generated in primary somatosensory cortex (S1; see [22,31] for MEG evidence on latencies of S1 sources). Although the cortical generators of the subsequent N90 component are not yet known, the fact that later SEP components such as the N140 (and their magnetic counterparts) have been linked to secondary somatosensory cortex (S2 [19,20,22]) suggests that the somatosensory N90 may also reflect early sensory-perceptual processing stages in modality-specific somatosensory areas, such as S1 or S2.…”

Section: Introductionmentioning

confidence: 99%

The electrophysiology of tactile extinction: ERP correlates of unconscious somatosensory processing

et al. 2002

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“…Simultaneous activation of separate SI areas and the different orientations of individual P20 dipole vectors might lead to a low amplitude or the occasional absence of an identifiable P20 in a poorly defined cerebral evoked potential. In addition, there might be occlusion due to convergence between the afferent inputs from proximal and distal parts of leg along the somatosensory pathway [10,11]. Furthermore, the poor SNR might also be due to anomalous innervation patterns in the lumbosacral spine.…”

Section: Discussionmentioning

confidence: 99%

Somatosensory evoked potential from S1 nerve root stimulation

Zhu

Jin

et al. 2011

Eur Spine J

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The objective of this study was to detect cerebral potentials elicited by proximal stimulation of the first sacral (S1) nerve root at the S1 dorsal foramen and to investigate latency and amplitude of the first cerebral potential. Tibial nerve SEP and S1 nerve root SEP were obtained from 20 healthy subjects and 5 patients with unilateral sciatic nerve or tibial nerve injury. Stimulation of the S1 nerve root was performed by a needle electrode via the S1 dorsal foramen. Cerebral potentials were recorded twice to document reproducibility. Latencies and amplitudes of the first cerebral potentials were recorded. Reproducible cerebral evoked potentials were recorded and P20s were identified in 36 of 40 limbs in the healthy subjects. The mean latency of P20 was 19.8 ± 1.6 ms. The mean amplitude of P20-N30 was 1.2 ± 0.9 lV. In the five patients, P40 of tibial nerve SEP was absent, while well-defined cerebral potentials of S1 nerve root SEP were recorded and P20 was identified from the involved side. This method may be useful in detecting S1 nerve root lesion and other disorders affecting the proximal portions of somatosensory pathway. Combined with tibial nerve SEP, it may provide useful information for diagnosis of lesions affecting the peripheral nerve versus the central portion of somatosensory pathway.

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The somatosensory evoked magnetic fields

Cited by 208 publications

References 133 publications

Neural Correlates of Tactile Detection: A Combined Magnetoencephalography and Biophysically Based Computational Modeling Study

Neural Correlates of Tactile Detection: A Combined Magnetoencephalography and Biophysically Based Computational Modeling Study

The electrophysiology of tactile extinction: ERP correlates of unconscious somatosensory processing

Somatosensory evoked potential from S1 nerve root stimulation

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