Suppression mechanisms of brainstem saccade generator by the caudal superior colliculus - Neural mechanisms of visual fixation -

尾上丘对脑干扫视发生器的抑制机制 - 视觉固定的神经机制 -

• 批准号: 17500271
• 负责人: SUGIUCHI Yuriko
• 金额: $ 2.24万
• 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 (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17500271/
• 关键词: superior colliculus; inhibitory burst neuron; pause neuron; saccade; visual fixation; superior colliculus; inhibitory burst neuron; pause neuron; saccade; visual fixation

The superior colliculus (SC) controls saccadic eye movement. In the SC, there is a motor map that reflects directions and amplitudes of saccades. Recently, it was proposed that neurons in the rostral SC maybe specifically involved in controlling fixation and suppressing saccades. Therefore, the rostral part of the SC is called the "fixation zone", whereas the remaining caudal part is called the "saccade zone". However, it was also reported that most fixation neurons do not pause for small contraversive saccades, but increase their activity. This finding has led the idea that fixation neurons are only the rostral extension of the saccade-related neurons in the more caudal colliculus. Therefore, the functional independence of the fixation zone in the rostral part has been controversial. In order to analyze the functional independence of the rostral part of the SC, we analyzed the neural connections from the rostral and caudal parts of the SC to inhibitory burst neurons (IBNs) and omnipause neurons (OPNs) using intracellular recording and straining methods in anesthetized cats.IBNs received monosynaptic excitatory postsynaptic potentials (EPSPs) from the contralateral caudal SC. They received disynaptic inhibitory postsynaptic potentials (IPSPs) from the ipsilateral caudal SC and bilateral rostral SCs. Lesion experiment suggested that the disynaptic IPSPs from the rostral parts of the bilateral SC was mediated by OPNs, and this was confirmed by the electrophysiological evidence. OPNs received monosynaptic EPSPs from the bilateral rostral SCs, and intracellular straining of such neurons showed projection to the contralateral excitatory burst neuron and IBN regions. These results indicate that the rostral of the SC directly activate OPNs and disynaptically inhibit IBNs via OPNs. The different pattern of synaptic input from the rostral and caudal SC to IBNs and OPNs indicated functional difference of the rostral part of the SC from its caudal part.

上丘（SC）控制着眼球的动作。在SC中，有一个电机图反映了扫视的方向和振幅。最近，有人提出，Rostral SC中的神经元可能专门参与控制固定和抑制扫视。因此，SC的延髓部分称为“固定区”，而其余的尾部则称为“扫视区”。但是，也有报道说，大多数固定神经元不会停止用于小小的对比性扫视，而是增加其活性。这一发现引起了这样的想法，即固定神经元只是较尾丘中与扫视相关的神经元的延伸。因此，定块部分中固定区的功能独立性存在争议。 In order to analyze the functional independence of the rostral part of the SC, we analyzed the neural connections from the rostral and caudal parts of the SC to inhibitory burst neurons (IBNs) and omnipause neurons (OPNs) using intracellular recording and straining methods in anesthetized cats.IBNs received monosynaptic excitatory postsynaptic potentials (EPSPs) from the对侧尾sc。他们从同侧尾sc和双侧鼻sc中获得了脱节抑制性突触后电位（IPSP）。病变实验表明，来自双侧SC的tho骨部分的无突触IPSP是由OPN介导的，并且通过电生理证据证实了这一点。 OPN从双侧sCS中接收单突触EPSP，此类神经元的细胞内扭曲显示对侧兴奋性爆发神经元和IBN区域的投影。这些结果表明，SC的主体直接激活OPN，并通过OPN抑制IBNS。突触输入的不同模式从尾sc和caudal sc到IBN和OPN表明，SC的尾部部分与尾部部分的功能差异。