Effects of task difficulty and target likelihood in area V4 of macaque monkeys
Effects of task difficulty and target likelihood in area V4 of macaque monkeys
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DOI：
10.1152/jn.01072.2005
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发表时间：
2006-11-01
影响因子：
2.5
通讯作者：
Maunsell, John H. R.
中科院分区：
文献类型：
--
作者：
Boudreau, C. Elizabeth;Williford, Tori H.;Maunsell, John H. R.
空间注意力提高了在被注意位置的表现，并相应地调节皮质神经元的放电率。这些行为和神经元效应的大小取决于在被注意位置所执行任务的难度。心理学理论家将此归因于在被注意位置对固定数量的加工资源更紧密的聚焦，但任务难度对注意力的神经元效应在整个视野中的分布的影响尚未得到充分探究。我们训练恒河猴做一项检测任务，其中难度和空间注意力被独立操控。探测刺激被用于测量在不同注意力和难度条件下的行为表现。动物在被注意的位置表现更好，并且这种优势随着难度增加而增大，这与来自人类心理物理学的数据一致。空间注意力引起的神经元调节在难度更大时更强。在两只动物中，无论空间注意力的位置如何，难度增加都会导致对视觉刺激的神经元反应适度增加。在第三只动物中，它之前被训练忽略多个干扰刺激，增加任务难度会增加在注意力焦点处的反应，并抑制远离注意力焦点的反应。结果表明，难度可以调节V4中空间注意力的效应；它可以以可能取决于主体行为策略的方式改变视觉场景中感觉反应的分布。
Spatial attention improves performance at attended locations and correspondingly modulates firing rates of cortical neurons. The size of these behavioral and neuronal effects depends on the difficulty of the task performed at the attended location. Psychological theorists have attributed this to a tighter focus of a fixed amount of processing resource at the attended location, but the effects of task difficulty on the distribution of neuronal effects of attention across the visual field have not been fully explored. We trained rhesus monkeys to do a detection task in which difficulty and spatial attention were manipulated independently. Probe stimuli were used to measure behavioral performance in different conditions of attention and difficulty. Animals performed better at attended locations and this advantage increased with difficulty, consistent with data from human psychophysics. Neuronal modulation by spatial attention was larger with greater difficulty. In two animals, increasing difficulty caused a modest increase in neuronal responses to visual stimuli regardless of the locus of spatial attention. In a third animal, which was previously trained to ignore multiple distracting stimuli, increasing task difficulty increased responses at the focus of attention and suppressed responses away from the focus of attention. The results show that difficulty can modulate effects of spatial attention in V4; it can alter the distribution of sensory responses across the visual scene in ways that may depend on the subject's behavioral strategy.