Martinez L, Lamas J A, Canedo A
Department of Physiology, Faculty of Medicine, Santiago de Compostela, Spain.
Neuroscience. 1995 Sep;68(1):195-206. doi: 10.1016/0306-4522(95)00133-4.
Extracellular single activity was recorded from pericruciate neurons in anaesthetized, paralysed, artificially ventilated cats. A total of 309 neurons were identified antidromically by stimulation of the dorsal column nuclei (229 from the nuneate nucleus and 80 from the gracile nucleus). The study addressed the question whether pericruciate-dorsal column nuclei neurons (corticonuclear cells) sent collaterals to the ipsilateral red nucleus and/or to the contralateral nucleus reticularis gigantocellularis. Also, the ipsilateral pyramidal tract was stimulated at mid-olivary level, as was the crossed corticospinal tract at C2, Th2 and L2 levels in order to know whether the corticonuclear cells sent their axons to the spinal cord and if so to which level. It was found that more than 95% of the corticonuclear fibres coursed through the pyramidal tract. A significant (28.4%; 88/309) proportion of the the corticonuclear neurons sent collaterals to the red nucleus and/or to the nucleus reticularis gigantocellularis. About 68% (209/309) of the corticonuclear cells did not send their axons to the spinal cord and the remainder were corticospinal neurons. Most of the corticospinal fibres terminated at the cervical level (72/100) and the remaining ended at thoracic (18/100) and lumbar (10/100) segments of the cord. While 63.4% (123/194) of the corticonuclear fibres coursing through the pyramidal tract and ending at supraspinal levels were slow conducting, the great majority of the corticospinal neurons were fast conducting (91/100). The non-corticospinal neurons were significantly slower conducting than the corticospinal cells. The corticogracile neurons were slower conducting than the corticocuneate cells. Of the 88 corticonuclear neurons that sent at least a branch to the sites tested, 50% branched into the red nucleus, 35.2% into the nucleus reticularis gigantocellularis and 14.7% into both nuclei, without significant difference between non-corticospinal and corticospinal cells. Most of the main axons of the corticonuclear cells ended at bulbar and cervical levels (281/309 or 90.9%). The data indicate that pericruciate-dorsal column nuclei neurons form a particular substrate within pyramidal tract cells. They can serve precise functions in motor coordination associated with the selection of their own sensory input. The results are discussed from this point of view.
在麻醉、麻痹并进行人工通气的猫身上，记录了十字周神经元的细胞外单活动。通过刺激背柱核（薄束核中的80个和楔束核中的229个），共逆向鉴定出309个神经元。本研究探讨了十字周 - 背柱核神经元（皮质核细胞）是否向同侧红核和/或对侧巨细胞网状核发出侧支的问题。此外，在橄榄中部水平刺激同侧锥体束，以及在C2、Th2和L2水平刺激交叉的皮质脊髓束，以了解皮质核细胞是否将其轴突发送到脊髓，如果是，则发送到哪个水平。发现超过95%的皮质核纤维通过锥体束走行。相当比例（28.4%；88/309）的皮质核神经元向红核和/或巨细胞网状核发出侧支。约68%（209/309）的皮质核细胞未将其轴突发送到脊髓，其余为皮质脊髓神经元。大多数皮质脊髓纤维终止于颈段（72/100），其余终止于胸段（18/100）和腰段（10/100）脊髓。虽然通过锥体束走行并终止于脊髓以上水平的皮质核纤维中有63.4%（123/194）传导速度较慢，但绝大多数皮质脊髓神经元传导速度较快（91/100）。非皮质脊髓神经元的传导速度明显慢于皮质脊髓细胞。皮质薄束神经元的传导速度慢于皮质楔束细胞。在88个至少向测试部位发出一个分支的皮质核神经元中，50%分支到红核，35.2%分支到巨细胞网状核，14.7%分支到两个核，非皮质脊髓细胞和皮质脊髓细胞之间无显著差异。皮质核细胞的大多数主要轴突终止于延髓和颈段水平（281/309或90.9%）。数据表明，十字周 - 背柱核神经元在锥体束细胞中形成了一种特殊的基质。它们可以在与自身感觉输入选择相关的运动协调中发挥精确的功能。从这个角度对结果进行了讨论。
