Luque M A, Pérez-Pérez M P, Herrero L, Waitzman D M, Torres B
Department of Physiology and Zoology, Fac. Biología, University of Sevilla, Avda. Reina Mercedes, 6, 41012 Sevilla, Spain.
Neuroscience. 2006 Feb;137(3):1051-73. doi: 10.1016/j.neuroscience.2005.09.033. Epub 2005 Nov 17.
Anatomical studies in goldfish show that the tectofugal axons provide a large number of boutons within the mesencephalic reticular formation. Electrical stimulation, reversible inactivation and cell recording in the primate central mesencephalic reticular formation have suggested that it participates in the control of rapid eye movements (saccades). Moreover, the role of this tecto-recipient area in the generation of saccadic eye movements in fish is unknown. In this study we show that the electrical microstimulation of the mesencephalic reticular formation of goldfish evoked short latency saccadic eye movements in any direction (contraversive or ipsiversive, upward or downward). Movements of the eyes were usually disjunctive. Based on the location of the sites from which eye movements were evoked and the preferred saccade direction, eye movements were divided into different groups: pure vertical saccades were mainly elicited from the rostral mesencephalic reticular formation, while oblique and pure horizontal were largely evoked from middle and caudal mesencephalic reticular formation zones. The direction and amplitude of pure vertical and horizontal saccades were unaffected by initial eye position. However the amplitude, but not the direction of most oblique saccades was systematically modified by initial eye position. At the same time, the amplitude of elicited saccades did not vary in any consistent manner along either the anteroposterior, dorsoventral or mediolateral axes (i.e. there was no topographic organization of the mesencephalic reticular formation with respect to amplitude). In addition to these groups of movements, we found convergent and goal-directed saccades evoked primarily from the anterior and posterior mesencephalic reticular formation, respectively. Finally, the metric and kinetic characteristics of saccades could be manipulated by changes in the stimulation parameters. We conclude that the mesencephalic reticular formation in goldfish shares physiological functions that correspond closely with those found in mammals.
对金鱼的解剖学研究表明，顶盖离中轴突在中脑网状结构内提供了大量的终扣。对灵长类动物中脑中央网状结构进行电刺激、可逆失活和细胞记录，结果表明该结构参与快速眼动（扫视）的控制。此外，这个顶盖接收区在鱼类扫视眼动产生过程中的作用尚不清楚。在本研究中，我们发现对金鱼中脑网状结构进行微电刺激可诱发任何方向（对侧或同侧、向上或向下）的短潜伏期扫视眼动。眼睛的运动通常是分离的。根据诱发眼动的部位位置和偏好的扫视方向，眼动被分为不同的组：纯垂直扫视主要从中脑网状结构的前部诱发，而倾斜和纯水平扫视则主要从中脑网状结构的中部和尾部区域诱发。纯垂直和水平扫视的方向和幅度不受初始眼位的影响。然而，大多数倾斜扫视的幅度而非方向会因初始眼位而系统地改变。同时，诱发扫视的幅度沿前后轴、背腹轴或内外侧轴均无一致的变化方式（即中脑网状结构在幅度方面不存在拓扑组织）。除了这些运动组，我们还发现了分别主要从中脑网状结构前部和后部诱发的汇聚性和目标导向性扫视。最后，扫视的度量和动力学特征可通过刺激参数的变化来操控。我们得出结论，金鱼的中脑网状结构具有与哺乳动物中发现的生理功能密切对应的生理功能。
