Sapountzis Panagiotis, Antoniadou Alexandra, Gregoriou Georgia G
Institute of Applied and Computational Mathematics, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece.
Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece.
PLoS Biol. 2025 Jan 27;23(1):e3003008. doi: 10.1371/journal.pbio.3003008. eCollection 2025 Jan.
Goal-directed behavior requires the effective suppression of distractions to focus on the task at hand. Although experimental evidence suggests that brain areas in the prefrontal and parietal lobe contribute to the selection of task-relevant and the suppression of task-irrelevant stimuli, how conspicuous distractors are encoded and effectively ignored remains poorly understood. We recorded neuronal responses from 2 regions in the prefrontal and parietal cortex of macaques, the frontal eye field (FEF) and the lateral intraparietal (LIP) area, during a visual search task, in the presence and absence of a salient distractor. We found that in both areas, salient distractors are encoded by both response enhancement and suppression by distinct neuronal populations. In FEF, a larger proportion of units displayed suppression of responses to the salient distractor compared to LIP, with suppression effects in FEF being correlated with search time. Moreover, in FEF but not in LIP, the suppression for the salient distractor compared to non-salient distractors that shared the target color could not be accounted for by an enhancement of target features. These results reveal a distinct contribution of FEF in the suppression of salient distractors. Critically, we found that in both areas, the population level representations of the target and singleton locations were not orthogonal, suggesting a mechanism of interference from salient stimuli.
目标导向行为需要有效抑制干扰以专注于手头任务。尽管实验证据表明前额叶和顶叶的脑区有助于选择与任务相关的刺激并抑制与任务无关的刺激，但显著干扰物是如何被编码并有效忽略的仍知之甚少。在一项视觉搜索任务中，我们记录了猕猴前额叶和顶叶皮质两个区域，即额眼区（FEF）和顶内沟外侧区（LIP），在有和没有显著干扰物情况下的神经元反应。我们发现，在这两个区域中，显著干扰物由不同神经元群体的反应增强和抑制来编码。在额眼区，与顶内沟外侧区相比，更大比例的神经元对显著干扰物的反应表现出抑制，额眼区的抑制效应与搜索时间相关。此外，在额眼区而非顶内沟外侧区，与共享目标颜色的非显著干扰物相比，对显著干扰物的抑制不能通过目标特征增强来解释。这些结果揭示了额眼区在抑制显著干扰物方面的独特作用。至关重要的是，我们发现，在这两个区域中，目标和单独物体位置的群体水平表征并非正交，这表明存在来自显著刺激的干扰机制。
