Separate evaluation of target facilitation and distractor suppression in the activity of macaque lateral intraparietal neurons during visual search
Separate evaluation of target facilitation and distractor suppression in the activity of macaque lateral intraparietal neurons during visual search
复制标题
视觉搜索过程中猕猴侧顶内神经元活动的目标促进和干扰抑制的单独评估
DOI：
10.1152/jn.00360.2013
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发表时间：
2013
影响因子：
2.5
通讯作者：
& Ogawa T
中科院分区：
文献类型：
--
作者：
Nishida S;Tanaka T;& Ogawa T
在视觉搜索过程中，侧顶叶内区（LIP）的神经元区分目标和干扰物，当目标出现在感受野内时比出现在感受野外时表现出更强的激活。一般认为，这种目标辨别活动是由目标相关的促进和干扰物相关的抑制共同作用产生的。然而，对于这两种类型的神经调节是如何构成目标辨别活动的，我们知之甚少。为了解决这个问题，我们记录了猴子在执行视觉搜索任务时的LIP活动，该任务包括目标存在和目标不存在的试验。在有目标存在的实验中，猴子必须向目标扫视，而在没有目标的实验中，猴子必须保持注视，而在只有分心物的实验中，猴子必须保持注视。通过将后一组实验的活性作为中性活性引入，我们能够将目标区分活性分为目标相关的提升成分和分心物相关的降低成分。我们发现，大多数LIP神经元的目标识别活动由目标相关升高和分心物相关降低相结合或仅目标相关升高组成。相比之下，仅在极少数神经元中观察到由分心物相关还原组成的目标辨别活动。我们还发现，平均而言，与分心物相关的降低相比，目标相关的升高更强，发生得更早。最后，我们考虑了可能的潜在机制，包括横向抑制相互作用，负责视觉搜索中的目标区分活动。目前的研究结果提供了在视觉搜索过程中神经元调节如何塑造目标区分活动的见解。
During visual search, neurons in the lateral intraparietal area (LIP) discriminate the target from distractors by exhibiting stronger activation when the target appears within the receptive field than when it appears outside the receptive field. It is generally thought that such target-discriminative activity is produced by the combination of target-related facilitation and distractor-related suppression. However, little is known about how the target-discriminative activity is constituted by these two types of neural modulation. To address this issue, we recorded activity from LIP of monkeys performing a visual search task that consisted of target-present and target-absent trials. Monkeys had to make a saccade to a target in the target-present trials, whereas they had to maintain fixation in the target-absent trials, in which only distractors were presented. By introducing the activity from the latter trials as neutral activity, we were able to separate the target-discriminative activity into target-related elevation and distractor-related reduction components. We found that the target-discriminative activity of most LIP neurons consisted of the combination of target-related elevation and distractor-related reduction or only target-related elevation. In contrast, target-discriminative activity composed of only distractor-related reduction was observed for very few neurons. We also found that, on average, target-related elevation was stronger and occurred earlier compared with distractor-related reduction. Finally, we consider possible underlying mechanisms, including lateral inhibitory interactions, responsible for target-discriminative activity in visual search. The present findings provide insight into how neuronal modulations shape target-discriminative activity during visual search.