Philiastides Marios G, Ratcliff Roger, Sajda Paul
Laboratory for Intelligent Imaging and Neural Computing, Department of Biomedical Engineering, Columbia University, New York, New York 10027, USA.
J Neurosci. 2006 Aug 30;26(35):8965-75. doi: 10.1523/JNEUROSCI.1655-06.2006.
When does the brain know that a decision is difficult to make? How does decision difficulty affect the allocation of neural resources and timing of constituent cortical processing? Here, we use single-trial analysis of electroencephalography (EEG) to identify neural correlates of decision difficulty and relate these to neural correlates of decision accuracy. Using a cued paradigm, we show that we can identify a component in the EEG that reflects the inherent task difficulty and not simply a correlation with the stimulus. We find that this decision difficulty component arises approximately 220 ms after stimulus presentation, between two EEG components that are predictive of decision accuracy [an "early" (170 ms) and a "late" (approximately 300 ms) component]. We use these results to develop a timing diagram for perceptual decision making and relate the component activities to parameters of a diffusion model for decision making.
大脑何时知道某个决策难以做出？决策难度如何影响神经资源的分配以及构成性皮层处理的时间？在此，我们采用脑电图（EEG）的单试次分析来识别决策难度的神经关联，并将这些关联与决策准确性的神经关联联系起来。使用线索范式，我们表明能够在脑电图中识别出一个成分，它反映了任务的固有难度，而不仅仅是与刺激的相关性。我们发现，这个决策难度成分在刺激呈现后约220毫秒出现，位于两个预测决策准确性的脑电图成分之间[一个“早期”（170毫秒）成分和一个“晚期”（约300毫秒）成分]。我们利用这些结果绘制了一个感知决策的时间图，并将成分活动与决策扩散模型的参数联系起来。
