Jain N, Florence S L, Qi H X, Kaas J H
Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
Proc Natl Acad Sci U S A. 2000 May 9;97(10):5546-50. doi: 10.1073/pnas.090572597.
Somatotopic maps in the cortex and the thalamus of adult monkeys and humans reorganize in response to altered inputs. After loss of the sensory afferents from the forelimb in monkeys because of transection of the dorsal columns of the spinal cord, therapeutic amputation of an arm or transection of the dorsal roots of the peripheral nerves, the deprived portions of the hand and arm representations in primary somatosensory cortex (area 3b), become responsive to inputs from the face and any remaining afferents from the arm. Cortical and subcortical mechanisms that underlie this reorganization are uncertain and appear to be manifold. Here we show that the face afferents from the trigeminal nucleus of the brainstem sprout and grow into the cuneate nucleus in adult monkeys after lesions of the dorsal columns of the spinal cord or therapeutic amputation of an arm. This growth may underlie the large-scale expansion of the face representation into the hand region of somatosensory cortex that follows such deafferentations.
成年猴子和人类大脑皮层及丘脑的躯体感觉定位图会因输入的改变而重新组织。在猴子因脊髓背柱横断、手臂治疗性截肢或外周神经背根横断而失去来自前肢的感觉传入后，初级躯体感觉皮层（3b区）中手部和手臂表征的被剥夺部分，会变得对来自面部的输入以及手臂剩余的任何传入信号产生反应。这种重组背后的皮层和皮层下机制尚不确定，且似乎是多方面的。在这里，我们表明，在脊髓背柱损伤或手臂治疗性截肢后，成年猴子脑干三叉神经核的面部传入神经会发芽并长入楔状核。这种生长可能是躯体感觉皮层中面部表征大规模扩展到手部区域的基础，而这种扩展是在上述去传入作用之后发生的。
