Neural organization of vertical saccadic eye movement

垂直扫视眼运动的神经组织

• 批准号: 08458267
• 负责人: SHINODA Yoshikazu
• 金额: $ 4.42万
• 依托单位: Tokyo Medical and Dental University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458267/
• 关键词: saccade; ocular motoneuron; biocytin; PPRF; HRP; superior colliculus; eye movement; neurophysiology

To understand the neural mechanisms of saccadic eye movement generation, the neural organization from the superior colliculuc (SC) to ocular motoneurons in the horizontal oculomotor system was analyzed in the anesthetized cat. Intracellular responses to stimulation ot the SC were analyzed in abducens motoneurons, medial rectus motoneurons and internuclear neurons (INNs) in the abducens nucleus. Abducens motoneurons received disynaptic excitatory inputs from the contralataeral SC via the ipsilateral paramedian pontine reticular formation (PPRF) and disynaptic inhibitory inputs from the ipsilateral SC via the contralateral PPRF.These electrophysiological findings were confirmed by anatomical experiments. Last-order premotor neurons were labeled transneuronally after injecting WGA-HRP into the abducens nerve, and in the same preparations dextran-biotin injection into the SC labeled axon terminals of tectoreticular neurons orthgradely in the contralateral PPRF rostral and caudal to the abducens nucleus. These axon terminals of tectoreticular fibers made direct contacts with last-order premotor neurons terminating on ipsilateral abducens motoneurons and contralateral abducens motoneurons. INNs in the abducens nucleus received disynaptic excitatory inputs from the contralateral SC and disynaptic inhibitory inputs from the ipsilateral SC.This pattern was the same as in abducens motoneurons. Medial rectus motoneurons received trisynaptic excitatory inputs from the ipsilateral SC via the contralateral INNs. Two groups of tectoreticular neurons were identified to convey output from the SC to the PPRF.One group projected to the PPRF,but not to the spinal cord, and the other group projected to both the PPRF and the spinal cord.

为了解跳跃性眼动产生的神经机制，对麻醉猫水平眼动系统中从上丘到眼动神经元的神经组织进行了分析。分析了外展运动神经元、内直肌运动神经元和外展核核间神经元对SC刺激的细胞内反应。外展运动神经元通过同侧旁脉桥状网状结构（PPRF）接收来自对侧SC的失突触兴奋输入，通过对侧PPRF接收来自同侧SC的失突触抑制输入。解剖实验证实了这些电生理结果。向外展神经注射WGA-HRP后，经神经元标记末级前运动神经元，在相同的制剂中，向外展核对侧PPRF吻侧和尾侧的构造网状神经元轴突末端注射葡聚糖生物素。这些织网纤维的轴突末端与末级运动前神经元直接接触，末级运动前神经元止于同侧外展运动神经元和对侧外展运动神经元。外展核内的神经元接受对侧SC的失突触兴奋输入和同侧SC的失突触抑制输入，这种模式与外展运动神经元相同。内侧直肌运动神经元通过对侧脑内神经接收同侧SC的三突触兴奋输入。确定了两组构造网状神经元将SC的输出传递到PPRF。一组投射到PPRF，但没有投射到脊髓，另一组同时投射到PPRF和脊髓。

项目成果

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Shinoda Y，Sugiuchi Y，Futami T，Kakei S，Izawa Y，Na J：“从六个半规管到上颈髓不同颈部肌肉运动神经元的四种输入汇聚模式。”

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Shinoda Y: "Input patterns and pathways from the six semicircular canals to motoneurons of neck muscles.II.The longissimus and semispinalis muscle groups." Journal of Neurophysiolgy. 77. 1234-1248 (1997)

Shinoda Y：“从六个半规管到颈部肌肉运动神经元的输入模式和路径。II.最长肌和半棘肌群。”

Na, J: "Cerebellar input to corticothalamic neurons in layers V and VI in the motor cortex." Neurosci.Res. 28. 77-91 (1997)

Na，J：“小脑对运动皮层 V 层和 VI 层皮质丘脑神经元的输入。”

Muto N: "Morphology of single axons of tectospinal neurons in the upper cervical spinal cord." J. Comp. Neurol.372. 9-26 (1996)

Muto N：“上颈脊髓顶盖神经元单轴突的形态。”