The most evident phenotype of degenerative motoneuron disease is the loss of motor function which accompanies motoneuron death. In both amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), it is now clear that dysfunction is not restricted to motoneurons but is manifest in the spinal circuits in which motoneurons are embedded. As mounting evidence shows that motoneurons possess more elaborate and extensive connections within the spinal cord than previously realized, it is necessary to consider the role of this circuitry and its dysfunction in the disease process. In this review article, we ask if the selective vulnerability of the different motoneuron types and the relative disease resistance of distinct motoneuron groups can be understood in terms of their intraspinal connections.

退化的运动神经元疾病的最明显表型是伴随运动神经元死亡的运动功能丧失。现在，在肌萎缩性侧索硬化症（ALS）和脊髓性肌萎缩症（SMA）中，功能障碍不仅限于运动神经元，而且还明显体现在嵌入运动神经元的脊髓回路中。越来越多的证据表明，运动神经元在脊髓内具有比以前意识到的更为复杂和广泛的连接，因此有必要考虑该电路的作用及其在疾病过程中的功能障碍。在这篇评论文章中，我们问是否可以通过它们的椎内连接来理解不同运动神经元类型的选择性脆弱性和不同运动神经元组的相对疾病抗性。