title: Usage of the middle finger shapes reorganization of the primary somatosensory cortex in patients with index finger amputation.
abstract: OBJECTIVE
  The primary somatosensory cortex (S1) is somatotopically reorganized after limb amputation. The duration of the amputation, the intensity of phantom limb pain but also a multifactoral model of altered cerebral input have been discussed to be associated with cortical changes. Patients with finger amputation rarely show phantom limb pain, the deafferented cortical area is small but other fingers might well overtake function.
  
  
  METHODS
  We selected a group of index finger amputated patients and performed a high resolution (in plane: 1.5 mm2) S1-mapping during tactile stimulation of finger tips.
  
  
  RESULTS
  We found an interhemispheric imbalance of the distance between the thumb and middle finger only for the patient-group. When patients used their middle finger more they showed less interhemispheric imbalance, increased spatial tactile discrimination and increased fMRI-activation in response to stimulation. Phantom limb pain was not associated with somatotopic representation parameters in S1.
  
  
  CONCLUSIONS
  Overall, our fMRI-data point to a usage dependent plasticity of Brodmann's area 3b in man.
authors.affiliation: Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Greifswald, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Oelschläger
authors.affiliation: Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Greifswald, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Pfannmöller
authors.affiliation: Department of Trauma and Orthopaedic Surgery, University of Greifswald, Greifswald, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Langner
authors.affiliation: Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Greifswald, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Lotze
mesh_terms: D000293:Adolescent; D000328:Adult; D000671:Amputation, Surgical; D016022:Case-Control Studies; D005260:Female; D005385:Fingers / Q000294:innervation*; D007839:Functional Laterality / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010591:Phantom Limb / Q000503:physiopathology*; D010812:Physical Stimulation; D013003:Somatosensory Cortex / Q000098:blood supply / Q000503:physiopathology*; D013028:Space Perception; D014110:Touch / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Amputation; S1; cortical plasticity; fMRI; primary somatosensory cortex; reorganization; somatotopy; usage factor