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Reduced somatosensory hand representation in thalidomide‐induced dysmelia as revealed by fMRI
Author(s) -
Stoeckel M. Cornelia,
Jörgens Silke,
Witte Otto W.,
Seitz Rüdiger J.
Publication year - 2005
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2005.03866.x
Subject(s) - somatosensory system , postcentral gyrus , thumb , psychology , neuroscience , anatomy , functional magnetic resonance imaging , secondary somatosensory cortex , motor cortex , somatosensory evoked potential , cortex (anatomy) , wrist , medicine , stimulation
The concept of cerebral plasticity suggests that the hand representation in somatosensory cortex is abnormal in congenital malformation disorders. To investigate this issue we studied 11 subjects with different degrees of upper extremity dysmelia due to thalidomide embryopathy in comparison to 10 control subjects. In the affected subjects fingers are typically missing in radio‐ulnar order beginning with the thumb. Haemodynamic responses to electrical stimulation of the radial‐most and ulnar‐most fingers were measured in each subject using functional magnetic resonance tomography. The size of the hand area in the primary somatosensory cortex was estimated by calculating the Euclidian distance between corresponding activation peaks on the lateral postcentral gyrus. The cortical somatosensory hand representation was found to be significantly smaller in dysmelic subjects as compared with the control subjects ( P < 0.001). The shrinkage of the hand area was not proportional to the number of missing fingers. Furthermore, the cortical representation of the ulnar fingers in the dysmelic subjects was shifted towards the cortical thumb representation of the control group. We suggest that the unproportional reduction of the hand area together with the observed shift may reflect use‐dependent rather than malformation‐induced reorganization of the somatosensory hand area.