title: Somatotopic arrangement of the corticospinal tract at the medullary pyramid in the human brain.
abstract: OBJECTIVE
  Somatotopic arrangements of the corticospinal tract (CST) in the human brain have been generally elucidated; however, very little is known about the somatotopy at the medullary pyramid (MP). Using diffusion tensor tractography (DTT), we investigated the somatotopic arrangement of the CST at the MP in the normal human brain.
  
  
  METHODS
  We recruited 30 healthy volunteers for this study. Diffusion tensor images were scanned using 1.5 T and the CSTs for hand and leg were obtained using FMRIB software. Normalized DTT was reconstructed using the Montreal Neurological Institute echo-planar imaging template supplied with the SPM software.
  
  
  RESULTS
  The hand somatotopy of the CST was located at the medial portion of the MP; in contrast, the leg somatotopy occupied the lateral portion of the MP.
  
  
  CONCLUSIONS
  We found that the somatotopies for hand and leg were arranged in the mediolateral direction at the MP in the human brain.
authors.affiliation: Department of Physical Therapy, Graduate School of Rehabilitation Science, Daegu University, Gyeongsangbuk-do, Republic of Korea.
authors.forename: Hyeok Gyu
authors.initials: HG
authors.lastname: Kwon
authors.forename: Ji Heon
authors.initials: JH
authors.lastname: Hong
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Lee
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Kwon
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Jang
mesh_terms: D000328:Adult; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D005260:Female; D006225:Hand / Q000294:innervation; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007866:Leg / Q000294:innervation; D008297:Male; D008526:Medulla Oblongata / Q000033:anatomy & histology*; D011712:Pyramidal Tracts / Q000033:anatomy & histology*; D055815:Young Adult