Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2006 Oct;105(4):588-94.
doi: 10.3171/jns.2006.105.4.588.

Motor field sensitivity for preoperative localization of motor cortex

Peter T Lin  1 , Mitchel S Berger, Srikantan S Nagarajan
Affiliations

Motor field sensitivity for preoperative localization of motor cortex

Peter T Lin et al. J Neurosurg. 2006 Oct.

Abstract

Object: In this study the role of magnetic source imaging for preoperative motor mapping was evaluated by using a single-dipole localization method to analyze motor field data in 41 patients.

Methods: Data from affected and unaffected hemispheres were collected in patients performing voluntary finger flexion movements. Somatosensory evoked field (SSEF) data were also obtained using tactile stimulation. Dipole localization using motor field (MF) data was successful in only 49% of patients, whereas localization with movement-evoked field (MEF) data was successful in 66% of patients. When the spatial distribution of MF and MEF dipoles in relation to SSEF dipoles was analyzed, the motor dipoles were not spatially distinct from somatosensory dipoles.

Conclusions: The findings in this study suggest that single-dipole localization for the analysis of motor data is not sufficiently sensitive and is nonspecific, and thus not clinically useful.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
Sample waveform showing traces obtained in a patient performing right index finger flexion.
Fig. 2
Fig. 2
Coronal MS images, posterior (left) and anterior (right) views, demonstrating somatosensory and motor source localizations derived from MEG data recorded during painless tactile stimulation of the right index finger (SSEF) and self-paced index finger flexion (MF and MEF). Data are shown for the unaffected hemisphere. Orange dot represents MEF; yellow dot, MF; and green dot, SSEF.
Fig. 3
Fig. 3
Graph showing the sensitivity of MF and MEF I data for the right, left, and both hemispheres.
Fig. 4
Fig. 4
Graphs depicting the location of MF and MEF I dipoles relative to SSEF dipoles in the unaffected hemisphere in individual patients with tumors.
Fig. 5
Fig. 5
Graphs illustrating the location of MF and MEF I dipoles relative to SSEF dipoles in the affected hemisphere in individual patients with tumors.
Fig. 6
Fig. 6
Bar graph depicting the mean distances (± standard error of the mean) between SSEF, and MF and MEF I dipoles. Distances were not significantly different between affected and unaffected sides. Only mediolateral distances were significantly greater than 0 (p < 0.05).
See this image and copyright information in PMC

References

    1. Castillo EM, Simos PG, Wheless JW, Baumgartner JE, Breier JI, Billingsley RL, et al. Integrating sensory and motor mapping in a comprehensive MEG protocol: clinical validity and replicability. Neuroimage. 2004;21:973–983. - PubMed
    1. Deecke L, Weinberg H, Brickett P. Magnetic fields of the human brain accompanying voluntary movement: Bereitschaftsmagnetfeld. Exp Brain Res. 1982;48:144–148. - PubMed
    1. Ebmeier K, Haberland N, Steenbeck J, Hochstetter A, Kalff R. Neuronavigation and magnetic source imaging in brain tumors. Front Radiat Ther Oncol. 1999;33:78–87. - PubMed
    1. Gallen CC, Schwartz BJ, Bucholz RD, Malik G, Barkley GL, Smith J, et al. Presurgical localization of functional cortex using magnetic source imaging. J Neurosurg. 1995;82:988–994. - PubMed
    1. Ganslandt O, Buchfelder M, Hastreiter P, Grummich P, Fahlbusch R, Nimsky C. Magnetic source imaging supports clinical decision making in glioma patients. Clin Neurol Neurosurg. 2004;107:20–26. - PubMed

Publication types

MeSH terms