Role of cerebellar pathways in gaze holding

小脑通路在凝视保持中的作用

• 批准号: 13480273
• 负责人: YOSHIDA Kaoru
• 金额: $ 5.57万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13480273/
• 关键词: Eye Movements; Flocculus; Vestibular Nucleus; Interstitial Nucleus of Cajal; GABA; Neural Integrator; 前庭動眼反射; ゲイン調節; 視線保持; 前庭二次ニューロン

For gaze maintenance, the velocity-encoded motor command must be integrated 'to produce an appropriate eye position command by a neural circuit called the oculomotor neural integrator. Cerebellar-brainstem interaction is necessary for this neural integration process. One possible substrate participating in this interaction is the cell groups of the paramedian tract (PMT). PMT neurons are known to project to the flocculus, but little is known about the firing behavior. In the present study, we searched the pontine PMT region for neurons discharging in relation to eye movements, In the MLF dorsal to the OPN area, there was a concentration of units that displayed burst-tonic firing pattern with upward on-direction (up-BT neurons). Their responses to electrical and natural vestibular stimulation indicated that they receive excitatory input from the contralateral anterior semicircular canal. They also received inputs from the interstitial nucleus of Cajal. Inactivation of up-BT cells by injection of muscimol, the GABA receptor agonist, consistently produced downbeat nystagmus. Unlike simple vestibular nystagmus, vertical gaze holding was impaired as indicated by an exponential time course of slow-phases (gaze-evoked nystagmus). Injection of bicuculline, the GABA receptor antagonist, caused upbeat nystagmus combined with gaze holding failure. These results thus suggests that the PMT-flocculus-vestibular nucleus pathway is important in maintaining both the..Stable gaze and vestibular balance

为了保持凝视，速度编码的运动命令必须被整合，以通过称为眼神经整合器的神经回路产生适当的眼睛位置命令。小脑-脑干的相互作用对于这种神经整合过程是必要的。参与这种相互作用的一种可能的底物是旁正中束（PMT）的细胞群。PMT神经元已知投射到小叶，但对放电行为知之甚少。在本研究中，我们在脑桥PMT区寻找与眼球运动有关的神经元放电。在OPN区背侧的MLF中，有一个集中的单位，显示向上的方向上的爆发性紧张放电模式（up-BT神经元）。它们对电刺激和自然前庭刺激的反应表明它们从对侧前半规管接受兴奋性输入。他们还接收来自卡哈尔间质核的输入。通过注射蝇蕈醇（GABA受体激动剂）灭活up-BT细胞，持续产生下搏性眼球震颤。与简单的前庭性眼震不同，垂直凝视保持受损，如慢相（凝视诱发的眼震）的指数时间过程所示。注射GABA受体拮抗剂荷包牡丹碱可引起上拍性眼球震颤并伴有凝视保持失败。因此，这些结果表明PMT-绒球-前庭核通路对于维持这两种功能都很重要。稳定凝视和前庭平衡

项目成果

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