Involvement of Purkinje cells in evoking saccadic eye movements by microstimulation of the posterior cerebellar vermis of monkeys.
Involvement of Purkinje cells in evoking saccadic eye movements by microstimulation of the posterior cerebellar vermis of monkeys.
复制标题
浦肯野细胞通过微刺激猴子小脑蚓部后部诱发眼跳运动。
DOI：
10.1152/jn.1987.57.5.1247
复制
发表时间：
1987
影响因子：
2.5
通讯作者：
Fujikado,T
中科院分区：
文献类型：
--
作者：
Noda,H;Fujikado,T
在被训练注视视觉目标的猴子中，研究了通过微刺激后蚓部引起扫视眼球运动的神经机制。低阈值区，扫视眼运动可以诱发电流小于10微安，局限于小叶VII在两只猴子，它包括一个后部的小叶VI（小叶维克）在另一只猴子。与扫视相关的神经活动记录的区域与低阈值区域一致。该区域对应于蚓部小叶，从该蚓部小叶记录眼睛位置和扫视相关的浦肯野细胞。在小叶VII的白色物质中注射红藻氨酸（红藻氨酸盐）导致注射部位半径1-2 mm内的浦肯野细胞严重损失。病变倾向于向外周小脑皮质更大，其通过传入和传出纤维的自然路线连接到注射部位。红藻氨酸管理后，眼跳相关的神经活动的分布没有显着不同的术前映射，尽管皮层神经元的严重损失。在注射部位附近的白色物质中可记录到苔藓纤维的爆发性放电，表明传入纤维相对不受红藻氨酸的影响。红藻氨酸给药后，微刺激后蚓部不能再诱发扫视性眼球运动。海人酸盐给药后引起扫视的刺激部位总是与完整的浦肯野细胞的存在有关。在这种情况下，引起扫视所需的最小电流取决于完整的浦肯野细胞的百分比。在正常浦肯野细胞层的叶，诱发扫视的幅度和方向和阈值唤起这样的眼球运动几乎可以与术前数据。眼球对后蚓部微刺激的扫视运动是由浦肯野细胞轴突传递的顺向冲动引起的。然而，对于电流小于10微安的第VII小叶所诱发的扫视，传入纤维的逆向激活并不是使眼球反射反应发生的神经机制。
Neural mechanisms for evoking saccadic eye movements by microstimulation of the posterior vermis were investigated in monkeys trained to fixate a visual target. The low-threshold region from which saccadic eye movements could be evoked with currents less than 10 microA was confined to lobule VII in two monkeys and it included a posterior part of lobule VI (lobule VIc) in another monkey. The region from which saccade-related neural activity was recordable coincided with the low-threshold region. This region corresponded to the vermal lobules from which eye position and saccade-related Purkinje cells were recorded. Kainic acid (kainate) injected in the white matter of lobule VII resulted in severe losses of Purkinje cells within a radius of 1-2 mm of the injection site. The lesion tended to be larger toward the peripheral cerebellar cortices, which were connected to the injection site by natural courses of the afferent and efferent fibers. After the kainate administration, the distribution of saccade-related neural activity did not differ significantly from that of the preoperative mapping, in spite of the severe losses of cortical neurons. Burst discharges of mossy fibers were recordable in the white matter near the injection site, indicating that afferent fibers were relatively unaffected by kainate. After kainate administration, the saccadic eye movements could no longer be evoked by microstimulation applied to the posterior vermis. The stimulus sites from which saccades could be evoked after kainate administration were always associated with the presence of intact Purkinje cells. In such cases, the minimum current necessary to evoke saccades depended on the percentages of intact Purkinje cells spared. In the folia with normal Purkinje cell layers, the amplitude and direction of evoked saccades and the thresholds for evoking such eye movements were almost comparable to the preoperative data. Saccadic eye movements in response to microstimulation of the posterior vermis were caused by orthodromic impulses conveyed through the axons of the Purkinje cells. Insofar as the saccades elicited from lobule VII with currents less than 10 microA are concerned, antidromic activation of the afferent fibers is not the neural mechanisms subserving the oculomotor responses.