Each of the descending pathways involved in motor control has a number of anatomical, molecular, pharmacological, and neuroinformatic characteristics. They are differentially involved in motor control, a process that results from operations involving the entire motor network rather than from the brain commanding the spinal cord. A given pathway can have many functional roles. This review explores to what extent descending pathways are highly conserved across species and concludes that there are actually rather widespread species differences, for example, in the transmission of information from the corticospinal tract to upper limb motoneurons. The significance of direct, cortico-motoneuronal (CM) connections, which were discovered a little more than 50 years ago, is reassessed. I conclude that although these connections operate in parallel with other less direct linkages to motoneurons, CM influence is significant and may subserve some special functions including adaptive motor behaviors involving the distal extremities.

中文翻译：

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运动控制中的下降途径。

运动控制涉及的每个下降途径均具有许多解剖学，分子，药理学和神经信息学特征。它们以不同的方式参与运动控制，该过程是由涉及整个运动网络的操作而不是由大脑指挥脊髓而产生的。给定的路径可以具有许多功能角色。这篇综述探索了物种间高度保守的下降途径的程度，并得出结论，实际上存在着相当广泛的物种差异，例如，从皮质脊髓束到上肢运动神经元的信息传递。重新评估了大约50年前发现的直接的皮质神经元（CM）连接的重要性。