Riley N M, Hodos W, Pasternak T
Pacific Graduate School of Psychology, Menlo Park, California.
Vis Neurosci. 1988;1(4):387-94. doi: 10.1017/s0952523800004156.
A serial-lesion technique was used to investigate interactions in visual processing between telencephalic components of the pigeon visual system. Pigeons were trained to discriminate pairs of stimuli that differed in color, intensity or pattern. After mastering the discrimination tasks, they were assigned to one of three groups. The first group (WI-EII) received lesions of the visual Wulst and were retested. After the discrimination tasks were again mastered, a second set of lesions was made, this time in the ectostriatum. The birds were tested once again after the second surgery. The second group (EI-WII), underwent the same sequence of events except that the order of the lesions was reversed. In the third group (E + W), lesions of both the visual Wulst and ectostriatum were made in a single operation, followed by retesting. The performance after the first lesion of the subjects in each of the two-stage lesion groups was typical of performance after such lesions; i.e. the birds with visual-Wulst lesions showed little or no impairment on any of the tasks, whereas the pigeons with ectostriatum lesions showed considerable deficits in intensity and pattern discrimination, which diminished after prolonged retraining. In contrast, the pigeons in the one-stage group (E + W) showed profound deficits that appeared to be permanent. The performance after the second operation of the WI-EII group was the same as that of pigeons with lesions of ectostriatum alone; i.e. destruction of ectostriatum first or second resulted in the same duration of impairment. The performance of the EI-WII group after its visual Wulst lesion, however, was similar to that observed in the E + W group. The results are interpreted as a reflection of parallel processing within the avian visual system; i.e. the presence of an intact tectofugal pathway may mask the effects of thalamofugal pathway interruption.
采用连续损伤技术研究鸽子视觉系统端脑各组成部分在视觉处理过程中的相互作用。训练鸽子辨别颜色、亮度或图案不同的刺激对。掌握辨别任务后，将它们分为三组。第一组（WI-EII）接受视叶的损伤并重新测试。再次掌握辨别任务后，进行第二次损伤，这次是在纹外体。第二次手术后再次对这些鸟进行测试。第二组（EI-WII）经历相同的事件序列，只是损伤顺序相反。第三组（E + W）在一次手术中对视叶和纹外体都进行损伤，然后重新测试。在两阶段损伤组中，每组实验对象在第一次损伤后的表现是此类损伤后的典型表现；即，视叶损伤的鸟在任何任务上几乎没有或没有损伤，而纹外体损伤的鸽子在亮度和图案辨别上表现出相当大的缺陷，经过长时间重新训练后这些缺陷有所减少。相比之下，单阶段组（E + W）的鸽子表现出严重的缺陷，而且似乎是永久性的。WI-EII组在第二次手术后的表现与仅纹外体损伤的鸽子相同；即，先或后破坏纹外体导致的损伤持续时间相同。然而，EI-WII组在视叶损伤后的表现与E + W组观察到的相似。结果被解释为鸟类视觉系统内并行处理的反映；即，完整的顶盖离中通路的存在可能掩盖丘脑离中通路中断的影响。
