Contribution of the primate superior colliculus to inhibition of return
Contribution of the primate superior colliculus to inhibition of return
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DOI：
10.1162/089892902760807249
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发表时间：
2002-11-15
影响因子：
3.2
通讯作者：
Munoz, DP
中科院分区：
文献类型：
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作者：
Dorris, MC;Klein, RM;Munoz, DP
返回抑制（IOR）现象在认知神经科学中引起了相当大的兴趣，因为它在视觉搜索中的假定功能作用，即在最近检查过的物体上放置抑制标签，以便进一步搜索新的项目。这种现象的许多行为参数已经被清楚地描绘出来，并且基于间接但收敛的证据，广泛持有的共识是中脑上级丘（SC）参与IOR的产生。我们之前已经训练过猴子进行扫视IOR任务，并表明它们以与人类相似的方式显示IOR。在这里，我们记录了单个神经元的活动，而猴子执行这个IOR任务的SC的表层和中间层。我们发现，当目标出现在先前提示的位置时，刺激相关的反应减弱，并且这种反应的幅度与随后的扫视反应时间相关。令人惊讶的是，在IOR期间观察到的活动衰减不是由这些神经元的主动抑制引起的，因为（a）事实上，在它们的反应场中呈现线索之后，它们更活跃，以及（B）当我们重复相同的实验，同时使用SC的电微刺激诱导的扫视反应时间来判断IOR任务期间SC回路的兴奋性水平时，我们发现更快的扫视是从线索位置引出的。我们的研究结果表明，灵长类SC参与IOR的表达，但SC不是抑制的网站。相反，SC中活性的降低反映了上游发生的信号降低。
The phenomenon of inhibition of return (IOR) has generated considerable interest in cognitive neuroscience because of its putative functional role in visual search, that of placing inhibitory tags on objects that have been recently inspected so as to direct further search to novel items. Many behavioral parameters of this phenomenon have been clearly delineated, and based on indirect but converging evidence, the widely held consensus is that the midbrain superior colliculus (SC) is involved in the generation of IOR. We had previously trained monkeys on a saccadic IOR task and showed that they displayed IOR in a manner similar to that observed in humans. Here we recorded the activity of single neurons in the superficial and intermediate layers of the SC while the monkeys performed this IOR task. We found that when the target was presented at a previously cued location, the stimulus-related response was attenuated and the magnitude of this response was correlated with subsequent saccadic reaction times. Surprisingly, this observed attenuation of activity during IOR was not caused by active inhibition of these neurons because (a) they were, in fact, more active following the presentation of the cue in their response field, and (b) when we repeated the same experiment while using the saccadic response time induced by electrical micro-stimulation of the SC to judge the level of excitability of the SC circuitry during the IOR task, we found faster saccades were elicited from the cued location. Our findings demonstrate that the primate SC participates in the expression of IOR; however, the SC is not the site of the inhibition. Instead, the reduced activity in the SC reflects a signal reduction that has taken place upstream.