Dissociating the Effect of Noise on Sensory Processing and Overall Decision Difficulty
Dissociating the Effect of Noise on Sensory Processing and Overall Decision Difficulty
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DOI：
10.1523/jneurosci.2725-10.2011
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发表时间：
2011-02-16
影响因子：
5.3
通讯作者：
Vidnyanszky, Zoltan
中科院分区：
文献类型：
--
作者：
Banko, Eva M.;Gal, Viktor;Vidnyanszky, Zoltan
已有研究提出知觉决策包含任务难度成分，该成分检测知觉不确定性并指导注意资源的分配。它被认为是在早期提取感觉信息后立即发生，并具体反映在事件相关电位的正向分量中，在刺激开始后类似于220ms时达到峰值。然而，在以前的研究中，与监控总体任务难度相关的神经过程被那些与增加刺激噪声导致的感觉加工需求增加相关的神经过程混淆。在这里，我们使用面孔性别分类任务来分离相位噪声对感觉加工和总体决策困难的影响。任务难度是通过在刺激中添加噪声或通过调整面部图像的男女特征来操纵的。我们发现，在人类刺激开始后的最初300ms内，是噪声的存在而不是总体任务难度的增加影响了电生理反应。此外，我们还表明，与完整的面孔相比，面孔的相位随机化处理与枕叶外侧皮质功能磁共振反应的增加有关。这些结果表明，噪声诱导的早期电生理反应的调制反映了视觉皮层加工需求的增加，因此无法支持发生在知觉决策的早期感觉加工阶段和后期感觉积累阶段之间的任务难度成分。
It has been proposed that perceptual decision making involves a task-difficulty component, which detects perceptual uncertainty and guides allocation of attentional resources. It is thought to take place immediately after the early extraction of sensory information and is specifically reflected in a positive component of the event related potentials, peaking at similar to 220 ms after stimulus onset. However, in the previous research, neural processes associated with the monitoring of overall task difficulty were confounded by those associated with the increased sensory processing demands as a result of adding noise to the stimuli. Here we dissociated the effect of phase noise on sensory processing and overall decision difficulty using a face gender categorization task. Task difficulty was manipulated either by adding noise to the stimuli or by adjusting the female/male characteristics of the face images. We found that it is the presence of noise and not the increased overall task difficulty that affects the electrophysiological responses in the first 300 ms following stimulus onset in humans. Furthermore, we also showed that processing of phase-randomized as compared to intact faces is associated with increased fMRI responses in the lateral occipital cortex. These results revealed that noise-induced modulation of the early electrophysiological responses reflects increased visual cortical processing demands and thus failed to provide support for a task-difficulty component taking place between the early sensory processing and the later sensory accumulation stages of perceptual decision making.