title: Characterization of short white matter fiber bundles in the central area from diffusion tensor MRI.
abstract: BACKGROUND
  Diffusion tensor imaging and tractography allow studying white matter fiber bundles in the human brain in vivo. Electrophysiological studies and postmortem dissections permit improving our knowledge about the short association fibers connecting the pre- and postcentral gyri. The aim of this study was first to extract and analyze the features of these short fiber bundles and secondly to analyze their asymmetry according to the subjects' handedness.
  
  
  METHODS
  Ten right-handed and ten left-handed healthy subjects were included. White matter fiber bundles were extracted using a streamline tractography approach, with two seed regions of interest (ROI) taken from a parcellation of the pre- and postcentral gyri. This parcellation was achieved using T1 magnetic resonance images (MRI) and semi-automatically generated three ROIs within each gyrus. MRI tracks were reconstructed between all pairs of ROIs connecting the adjacent pre- and postcentral gyri. A quantitative analysis was performed on the number of tracks connecting each ROI pair. A statistical analysis studied the repartition of these MRI tracks in the right and left hemispheres and as a function of the subjects' handedness.
  
  
  RESULTS
  The quantitative analysis showed an increased density of MRI tracks in the middle part of the central area in each hemisphere of the 20 subjects. The statistical analysis showed significantly more MRI tracks for the left hemisphere, when we consider the whole population, and this difference was presumably driven by the left-handers.
  
  
  CONCLUSIONS
  These results raise questions about the functional role of these MRI tracks and their relation with laterality.
authors.affiliation: Equipe MediCIS, Faculté de Médecine, INSERM U 1099/Université de Rennes 1, Rennes Cedex, France. elsa.magro@chu-brest.fr
authors.forename: Elsa
authors.initials: E
authors.lastname: Magro
authors.forename: Tristan
authors.initials: T
authors.lastname: Moreau
authors.forename: Romuald
authors.initials: R
authors.lastname: Seizeur
authors.forename: Bernard
authors.initials: B
authors.lastname: Gibaud
authors.forename: Xavier
authors.initials: X
authors.lastname: Morandi
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*; D055815:Young Adult