Sensory Gain Outperforms Efficient Readout Mechanisms in Predicting Attention-Related Improvements in Behavior
Sensory Gain Outperforms Efficient Readout Mechanisms in Predicting Attention-Related Improvements in Behavior
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DOI：
10.1523/jneurosci.2277-14.2014
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发表时间：
2014-10-01
影响因子：
5.3
通讯作者：
Serences, John T.
中科院分区：
文献类型：
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作者：
Itthipuripat, Sirawaj;Ester, Edward F.;Serences, John T.
空间注意被认为通过几种不同的机制促进知觉处理。例如，注意力可以放大感觉区域的神经反应（感觉增益），调节神经变异性（噪音调制），或者改变感觉后决策机制选择性读出感觉信号的方式（有效读出）。即使在简单的行为任务的背景下，也不清楚这些机制中的每一个都可以解释注意力调节的行为变化和神经活动之间的关系，因为很少有研究系统地映射刺激强度，注意力集中，神经活动和行为表现之间的变化。在这里，我们使用了心理物理学，事件相关电位（ERP）和定量建模的组合，明确链接到注意相关的感知灵敏度的变化与人类观察者记录的ERP幅度的变化。空间注意导致早期感觉ERP成分（P1，峰值类似于刺激后80-130 ms）和晚期正偏转成分（峰值类似于刺激后230-330 ms）的振幅成倍增加。基于信号检测理论的一个简单模型表明，这些乘性增益变化足以解释感知灵敏度中与注意力相关的改善，而不需要调用噪声调制。此外，结合所观察到的乘法增益与postsensory读出机制导致所观察到的行为数据的描述显着较差。我们的结论是，至少在相对简单的视觉辨别任务的背景下，空间注意主要通过调节早期感觉加工过程中神经反应的增益来调节知觉灵敏度
Spatial attention has been postulated to facilitate perceptual processing via several different mechanisms. For instance, attention can amplify neural responses in sensory areas (sensory gain), mediate neural variability (noise modulation), or alter the manner in which sensory signals are selectively read out by postsensory decision mechanisms (efficient readout). Even in the context of simple behavioral tasks, it is unclear how well each of these mechanisms can account for the relationship between attention-modulated changes in behavior and neural activity because few studies have systematically mapped changes between stimulus intensity, attentional focus, neural activity, and behavioral performance. Here, we used a combination of psychophysics, event-related potentials (ERPs), and quantitative modeling to explicitly link attention-related changes in perceptual sensitivity with changes in the ERP amplitudes recorded from human observers. Spatial attention led to a multiplicative increase in the amplitude of an early sensory ERP component (the P1, peaking similar to 80-130 ms poststimulus) and in the amplitude of the late positive deflection component (peaking similar to 230-330 ms poststimulus). A simple model based on signal detection theory demonstrates that these multiplicative gain changes were sufficient to account for attention-related improvements in perceptual sensitivity, without a need to invoke noise modulation. Moreover, combining the observed multiplicative gain with a postsensory readout mechanism resulted in a significantly poorer description of the observed behavioral data. We conclude that, at least in the context of relatively simple visual discrimination tasks, spatial attention modulates perceptual sensitivity primarily by modulating the gain of neural responses during early sensory processing