Integration of exogenous input into a dynamic salience map revealed by perturbing attention
Integration of exogenous input into a dynamic salience map revealed by perturbing attention
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DOI：
10.1523/jneurosci.1898-06.2006
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发表时间：
2006-09-06
影响因子：
5.3
通讯作者：
Gottlieb, Jacqueline
中科院分区：
文献类型：
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作者：
Balan, Puiu F.;Gottlieb, Jacqueline
尽管人们普遍认为外源性因素和自愿性因素共同决定了注意力的来源，但人们对这些因素的整合规则却知之甚少。我们研究了在任务执行过程中，大脑顶叶外侧区(LIP)对短暂的、分散注意力的视觉干扰的神经反应。猴子执行一项隐蔽的搜索任务，在这项任务中，它们辨别嵌入在干扰物中的目标的方向，并在任务执行过程中的不同时刻和位置呈现短暂的视觉扰动。嘴唇神经元对由新物体的出现以及现有物体的颜色、亮度或位置的突然变化组成的扰动做出反应。嘴唇反应与不同干扰类型的自下而上行为效应相关。此外，神经元表现出两种类型的自上而下的调制。一种调制是上下文特定的乘性增益，它以一种空间上非特定的方式影响扰动、目标和分心因子的活动。在扰动直接标记目标位置的试验块中，增益高于在它们总是出现在目标对面的块中，从而编码由目标和扰动位置之间的统计偶然性定义的行为上下文。第二种调制反映了与搜索相关活动的局部竞争相互作用，导致了相反的效应：当扰动出现在目标位置时，扰动诱发的反应比出现在目标对面时更弱。因此，LIP编码了一个由局部和全局自上而下机制塑造的突显的抽象维度。这些相互作用的机制作为行为背景和瞬间任务需求的函数来调节对外部输入的反应。
Although it is widely accepted that exogenous and voluntary factors jointly determine the locus of attention, the rules governing the integration of these factors are poorly understood. We investigated neural responses in the lateral intraparietal area ( LIP) to transient, distracting visual perturbations presented during task performance. Monkeys performed a covert search task in which they discriminated the orientation of a target embedded among distractors, and brief visual perturbations were presented at various moments and locations during task performance. LIP neurons responded to perturbations consisting of the appearance of new objects, as well as to abrupt changes in the color, luminance, or position of existing objects. The LIP response correlated with the bottom-up behavioral effects of different perturbation types. In addition, neurons showed two types of top-down modulations. One modulation was a context-specific multiplicative gain that affected perturbation, target, and distractor activity in a spatially nonspecific manner. Gain was higher in blocks of trials in which perturbations directly marked target location than in blocks in which they invariably appeared opposite the target, thus encoding a behavioral context defined by the statistical contingency between target and perturbation location. A second modulation reflected local competitive interactions with search-related activity, resulting in the converse effect: weaker perturbation-evoked responses if perturbations appeared at the location of the target than if they appeared opposite the target. Thus, LIP encodes an abstract dimension of salience, which is shaped by local and global top-down mechanisms. These interacting mechanisms regulate responsiveness to external input as a function of behavioral context and momentary task demands.