Schiller P H, Sandell J H, Maunsell J H
J Neurophysiol. 1987 Apr;57(4):1033-49. doi: 10.1152/jn.1987.57.4.1033.
Rhesus monkeys were trained to make saccadic eye movements to visual targets using detection and discrimination paradigms in which they were required to make a saccade either to a solitary stimulus (detection) or to that same stimulus when it appeared simultaneously with several other stimuli (discrimination). The detection paradigm yielded a bimodal distribution of saccadic latencies with the faster mode peaking around 100 ms (express saccades); the introduction of a pause between the termination of the fixation spot and the onset of the target (gap) increased the frequency of express saccades. The discrimination paradigm, on the other hand, yielded only a unimodal distribution of latencies even when a gap was introduced, and there was no evidence for short-latency "express" saccades. In three monkeys either the frontal eye field or the superior colliculus was ablated unilaterally. Frontal eye field ablation had no discernible long-term effects on the distribution of saccadic latencies in either the detection or discrimination tasks. After unilateral collicular ablation, on the other hand, express saccades obtained in the detection paradigm were eliminated for eye movements contralateral to the lesion, leaving only a unimodal distribution of latencies. This deficit persisted throughout testing, which in one monkey continued for 9 mo. Express saccades were not observed again for saccades contralateral to the lesion, and the mean latency of the contralateral saccades was longer than the mean latency of the second peak for the ipsiversive saccades. The latency distribution of saccades ipsiversive to the collicular lesion was unaffected except for a few days after surgery, during which time an increase in the proportion of express saccades was evident. Saccades obtained with the discrimination paradigm yielded a small but reliable increase in saccadic latencies following collicular lesions, without altering the shape of the distribution. Unilateral muscimol injections into the superior colliculus produced results similar to those obtained immediately after collicular lesions: saccades contralateral to the injection site were strongly inhibited and showed increased saccadic latencies. This was accompanied by a decrease of ipsilateral saccadic latencies and an increase in the number of saccades falling into the express range. The results suggest that the superior colliculus is essential for the generation of short-latency (express) saccades and that the frontal eye fields do not play a significant role in shaping the distribution of saccadic latencies in the paradigms used in this study.(ABSTRACT TRUNCATED AT 400 WORDS)
恒河猴通过检测和辨别范式接受训练，使其向视觉目标进行快速眼动，在这些范式中，它们需要向单个刺激（检测）或与其他几个刺激同时出现的同一刺激进行快速眼动（辨别）。检测范式产生了快速眼动潜伏期的双峰分布，较快的模式在100毫秒左右达到峰值（快速扫视）；在注视点终止和目标出现之间引入一个停顿（间隙）增加了快速扫视的频率。另一方面，辨别范式即使引入间隙也只产生了潜伏期的单峰分布，并且没有证据表明存在短潜伏期的“快速”扫视。在三只猴子中，单侧切除额叶眼区或上丘。额叶眼区切除对检测或辨别任务中快速眼动潜伏期的分布没有明显的长期影响。另一方面，单侧上丘切除后，在检测范式中获得的快速扫视在与损伤对侧的眼动中被消除，只留下潜伏期的单峰分布。这种缺陷在整个测试过程中持续存在，其中一只猴子持续了9个月。对于与损伤对侧的扫视，再也没有观察到快速扫视，并且对侧扫视的平均潜伏期比对侧性扫视的第二个峰值的平均潜伏期更长。除了手术后的几天，与上丘损伤同侧的扫视潜伏期分布没有受到影响，在此期间快速扫视的比例明显增加。上丘损伤后，辨别范式获得的扫视潜伏期有小幅但可靠的增加，而分布形状没有改变。向上丘单侧注射蝇蕈醇产生的结果与上丘损伤后立即获得的结果相似：注射部位对侧的扫视受到强烈抑制，并且快速眼动潜伏期增加。这伴随着同侧快速眼动潜伏期的减少和落入快速范围内的扫视数量的增加。结果表明，上丘对于短潜伏期（快速）扫视的产生至关重要，并且额叶眼区在本研究使用的范式中对快速眼动潜伏期分布的形成没有显著作用。（摘要截于400字）
