Functional hemispheric asymmetry assessment in a visual language task using MEG

Brain Topogr. 1998 Fall;11(1):57-65. doi: 10.1023/a:1022270620396.

Abstract

We used magnetoencephalography (MEG) to assess the degree of hemispheric activation in eleven normal, right-handed subjects with no history of neurological disorder or learning disability during performance of a word- and a face-recognition tasks. Neuromagnetic activity was recorded using a whole-head system, and the sources of the recorded magnetic fields were modeled as single equivalent current dipoles. Early (<200 msec) cerebral activation, defined by the number of dipoles identified by the data-fitting algorithm, was localized in the occipital cortex during both tasks, as expected. During the language task, the extent of the later (>200 msec) cerebral activation was approximately double in the left hemisphere in almost all subjects, involving temporal and temporoparietal areas. In contrast, during the face-recognition task, the corresponding activation was mostly symmetrical across the two occipital lobes, also involving the posterior-inferior aspect of the right temporal lobe. Our results suggest that the MEG is a suitable method of assessing noninvasively hemispheric specialization for language.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Algorithms
  • Brain Mapping / methods*
  • Evaluation Studies as Topic
  • Female
  • Functional Laterality / physiology
  • Humans
  • Language*
  • Magnetoencephalography*
  • Male
  • Mental Recall / physiology*
  • Pattern Recognition, Visual / physiology*