title: Magnetoencephalography indicates finger motor somatotopy.
abstract: The existence or non-existence of fine-scale motor somatotopy of the hand is a fundamental problem with regard to the functioning of the human brain. In contrast to seldom contradicted early twentieth century descriptions of activation overlap, descriptions of finger motor somatotopy faced disagreement. Recent blood-flow-related brain mapping data achieved with functional magnetic resonance imaging (fMRI) argue in favour of fine-scale somatotopy. However, considerable discrepancies between blood oxygen-level-dependent fMRI activations and intracortically recorded neuronal activity have been reported and it is unclear whether the blood flow results truly reflect the neuronal situation. We have used recent advances in magnetoencephalography to detect signals deriving directly from neuronal tissue. Besides replication of the overlap aspect, we found statistically significant evidence for the existence of a somatotopic aspect of human hand motor representation when comparing the fifth and first finger motor dipoles along the superior-inferior axis. The average location of the fifth finger was found to be 2.31 mm superior to the first finger.
authors.affiliation: Department of Neurology, General Hospital and University of Vienna, Vienna, Austria. roland.beisteiner@akh-wien.ac.at
authors.forename: Roland
authors.initials: R
authors.lastname: Beisteiner
authors.forename: Andreas
authors.initials: A
authors.lastname: Gartus
authors.forename: Marcus
authors.initials: M
authors.lastname: Erdler
authors.forename: Dagmar
authors.initials: D
authors.lastname: Mayer
authors.forename: Rupert
authors.initials: R
authors.lastname: Lanzenberger
authors.forename: Lüder
authors.initials: L
authors.lastname: Deecke
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D005385:Fingers / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*