Neurophysiological Analysis of Spinoderebellar Tract Neurones of the Thoracic Segments in Relation to Respiratory Movement

在每个脊髓节段中，存在两组脊髓小脑束（SCT）神经元，一组具有不交叉的上行轴突，另一组具有交叉的上行轴突。为了了解它们之间是否存在功能差异，在呼吸期间在胸段检查了通过非交叉和交叉SCT传输到小脑的信息类型。在戊巴比妥钠（35 mg/Kg）麻醉、泮库溴铵麻痹后人工通气的猫上，记录小脑和上颈髓的非交叉和交叉SCT神经元的活动。通过记录膈神经活动（反映中枢呼吸节律）和胸部运动监测节律性呼吸运动。34个SCT神经元显示与呼吸某些方面有关的节律性活动。主要位于Clarke柱的22个未交叉SCT神经元的神经活动被锁定到呼吸泵循环。由于这种节律性即使在迷走神经切断术后仍然存在，但在气胸后消失，未交叉SCT神经元的节律性活动可能是由胸壁的流入引起的。另一方面，交叉SCT神经元的节律性活动在气胸后仍然存在，并与膈神经的节律性活动一致，提示节律性的中枢起源;在自主呼吸时，一些交叉SCT神经元的节律性活动减弱或消失，这表明交叉SCT可能整合了中枢和外周输入。

In each spinal segment, there exist two grtoups of spinocerebellar tract (SCT) neurones ; one having uncrossed and the other crossed ascending axons. To see if there is a functional difference between them, the kind of information transmitted to the cerebellum through uncrossed and crosses SCTs was examined in the thoracic segments during respiration. Recordings of activity of uncrossed and crossed SCT neurones identified by antidromic activation from the cerebellum and upper cervical spinal cord were made in the cat anesthetized with pentobarbital sodium (35mg/Kg), and artificially ventilated after being paralyzed with pancuronium bromide. Rhythmic respiratory movement was monitored by recording phrenic nerve activity (reflecting central respiratory rhythm) and by thorax movement.Thirty four SCT neurones showed rhythmic activities in relation to some aspects of respiration. Neural activity of 22 uncrossed SCT neurones located in mainly the Clarke's column was locked to the respiratory pump cycle. Because this rhythmicity still remained even after vagotomy, but disappeared after pneumothorax, rhythmic activity of uncrossed SCT neurones may be caused by inflow from the chest wall. On the other hand, rhythmic activity of crossed SCT neurones remained and coincided with the phrenic nerve activity even after pneumothorax, suggesting the central genesis of the rhythmcity.During spontaneous respiration, rhythmic activity of some crossed SCT neurones, which was clearly seen under artificial ventilation, became weak or disappeared, suggesting that crossed SCT may integrate central and peripheral inputs.