Easter S S, Schmidt J T, Leber S M
J Embryol Exp Morphol. 1978 Jun;45:145-59.
Adult goldfish had one tectal lobe removed surgically, and several months later, the eye contralateral to the missing tectum was injected with radioactive proline. Radioautographs of the brains were studied to trace the paths and termination sites of the optic fibers. The optic tract decussated at the chiasm, as normally, but then ran caudally in a large neuroma on the tectum-less side of the brain. Substantial numbers of fibers left this neuroma to enter two or more of five commissures, through which they recrossed the midline. These commissures: transverse, minor, horizontal, posterior and ansate, ordinarily contain few or no optic fibers. All are normally linked with the tectum. Negligible numbers of aberrant optic fibers recrossed the midline elsewhere. On the intact side of the brain, ipsilateral to the injected eye, the optic fibers innervated some or all of the nuclei and areas normally served by contralateral retinal fibers. An earlier behavioral study of these same fish had shown that some of them made reversed optokinetic nystagmus in response to stripe movement seen by the eye projecting ipsilaterally; others failed to respond to stimuli through this eye. In all the reversed responders, a caudal group of retinal projection sites was labeled ipsilaterally. This included the basal optic nucleus and the caudal portions of nucleus dorsolateralis thalami and area pretectalis. In the non-responders, these targets were not labeled ipsilaterally. Together, these results suggest that one or more of these three sites is or are responsible for optokinetic nystagmus in normal goldfish.
成年金鱼的一个视叶被手术切除，几个月后，对与缺失视叶相对侧的眼睛注射放射性脯氨酸。研究大脑的放射自显影片以追踪视神经纤维的路径和终止部位。视束在视交叉处像正常情况一样交叉，但随后在大脑无视叶一侧的一个大神经瘤中向尾侧延伸。大量纤维离开这个神经瘤进入五个连合中的两个或更多个，通过这些连合它们再次穿过中线。这些连合：横连合、小连合、水平连合、后连合和袢连合，通常含有很少或没有视神经纤维。它们通常都与视叶相连。只有极少数异常视神经纤维在其他部位再次穿过中线。在注射眼同侧的大脑完整侧，视神经纤维支配了一些或全部通常由对侧视网膜纤维供应的核团和区域。对这些相同金鱼早期的行为研究表明，其中一些金鱼对同侧投射眼看到的条纹运动做出反向视动性眼球震颤；其他金鱼则对通过这只眼睛的刺激没有反应。在所有做出反向反应的金鱼中，一组尾侧视网膜投射部位在同侧被标记。这包括基底视核以及丘脑背外侧核和顶盖前区的尾侧部分。在没有反应的金鱼中，这些靶点在同侧没有被标记。总之，这些结果表明这三个部位中的一个或多个在正常金鱼的视动性眼球震颤中起作用。
