title: Comparison of cortical activation patterns by somatosensory stimulation on the palm and dorsum of the hand.
abstract: OBJECTIVE
  Little is known about differences of cortical activation according to body location. We attempted to compare brain activation patterns by somatosensory stimulation on the palm and dorsum of the hand, using functional magnetic resonance imaging (fMRI).
  
  
  METHODS
  We recruited 15 healthy right-handed volunteers for this study. fMRI was performed during touch stimulation using a rubber brush on an area of the same size on the palm or dorsum of the hand. Regions of interest (ROIs) were drawn at the primary sensory-motor cortex (SM1), posterior parietal cortex, and secondary somatosensory cortex.
  
  
  RESULTS
  Group analysis of fMRI data indicated that touch stimulation on the palm resulted in production of more activated voxels in the contralateral SM1 and posterior parietal cortex than on the dorsum of the hand. The most activated ROI was found to be the contralateral SM1 by stimulation of the palm or dorsum, and the number of activated voxels (5875) of SM1 by palm stimulation was more than 2 times that (2282) of dorsum stimulation. The peak activated value in the SM1 by palm stimulation (16.43) was also higher than that of the dorsum (5.52).
  
  
  CONCLUSIONS
  We found that stimulation of the palm resulted in more cortical activation in the contralateral SM1 than stimulation of the dorsum. Our results suggested that the palm of the hand might have larger somatotopy of somatosensory representation for touch in the cerebral cortex than the dorsum of the hand. Our results would be useful as a rehabilitation strategy when more or less somatosensory stimulation of the hand is necessary.
authors.affiliation: Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daegu, Republic of Korea.
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Jang
authors.forename: Jeong Pyo
authors.initials: JP
authors.lastname: Seo
authors.forename: Sang Ho
authors.initials: SH
authors.lastname: Ahn
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Lee
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D005260:Female; D006225:Hand / Q000033:anatomy & histology / Q000294:innervation*; D006358:Hot Temperature; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008663:Metacarpus / Q000294:innervation*; D010100:Oxygen / Q000097:blood; D010812:Physical Stimulation; D012684:Sensory Thresholds / Q000502:physiology*; D014110:Touch; D055815:Young Adult
chemical_list: D010100:Oxygen