Localizing the central sulcus by functional magnetic resonance imaging and magnetoencephalography.

To further validate the potential of functional magnetic resonance imaging (fMRI) for localization of the sensorimotor cortex, fMRI was compared with somatosensory evoked fields (SEFs) in eight normal volunteers. A conventional 1.5 T MRI scanner and an MRI-linked 66-channel whole head magnetoencephalography system were used. fMRI activated by unilateral hand squeeze movement indicated the highest activation on the central sulci that were localized by SEFs in all 16 contralateral hemispheres. This indicates that although the fMRI signal activation may originate from a vein running along the central sulcus, fMRI is reliable to detect the central sulcus. The pre-central gyrus also indicated some signal activation on fMRI implying better visualization of spatial distribution of activation. fMRI and SEFs are complementary methods for localizing the central sulcus.