McClellan A D
Department of Physiology and Biophysics, University of Iowa, Iowa City 52242.
Brain Res. 1988 Aug 9;457(2):338-49. doi: 10.1016/0006-8993(88)90704-4.
The lamprey brainstem contains a 'command system' which descends into the spinal cord to activate motor networks and initiate locomotion. In the present study, partial lesions were made in the rostral spinal cord in order to spare various tracts and determine which tracts carry the descending command signal to the spinal cord. Sparing the medial areas of the rostral spinal cord usually blocked both sensory-evoked and spontaneous locomotion, while sparing the lateral regions of the rostral spinal cord did not abolish voluntary locomotor activity. Either the ventrolateral or dorsolateral spinal tracts could support the initiation of locomotion. Brainstem structures rostral to the mesencephalon were not necessary for the initiation of locomotor behavior. The data indicate that the lateral spinal tracts contain a significant part of the descending command pathway for locomotion. In contrast, the medial spinal tracts were neither necessary nor usually sufficient to support locomotor behavior, suggesting that the larger reticulospinal Muller cells, which project in these tracts, do not contribute significantly to the initiation of locomotion.
七鳃鳗脑干包含一个“指令系统”，该系统下行至脊髓以激活运动网络并启动运动。在本研究中，对延髓脊髓进行部分损伤，以保留各种神经束，并确定哪些神经束将下行指令信号传递至脊髓。保留延髓脊髓的内侧区域通常会阻断感觉诱发运动和自发运动，而保留延髓脊髓的外侧区域并不会消除自主运动活动。腹外侧或背外侧脊髓束均可支持运动的启动。中脑前方的脑干结构对于运动行为的启动并非必需。数据表明，外侧脊髓束包含运动下行指令通路的重要部分。相比之下，内侧脊髓束对于支持运动行为既非必需，通常也不充分，这表明投射至这些神经束的较大的网状脊髓Muller细胞对运动的启动贡献不大。
