Ratcliff Roger, Sederberg Per B, Smith Troy A, Childers Russ
The Ohio State University, United States.
The Ohio State University, United States.
Neuropsychologia. 2016 Dec;93(Pt A):128-141. doi: 10.1016/j.neuropsychologia.2016.09.026. Epub 2016 Sep 29.
Recent work in perceptual decision-making has shown that although two distinct neural components differentiate experimental conditions (e.g., did you see a face or a car), only one tracked the evidence guiding the decision process. In the memory literature, there is a distinction between a fronto-central evoked potential measured with EEG beginning at 350ms that seems to track familiarity and a late parietal evoked potential that peaks at 600ms that tracks recollection. Here, we applied single-trial regressor analysis (similar to multivariate pattern analysis, MVPA) and diffusion decision modeling to EEG and behavioral data from two recognition memory experiments to test whether these two components contribute to the recognition decision process. The regressor analysis only involved whether an item was studied or not and did not involve any use of the behavioral data. Only late EEG activity distinguishes studied from not studied items that peaks at about 600ms following each test item onset predicted the diffusion model drift rate derived from the behavioral choice and reaction times (but only for studied items). When drift rate was made a linear function of the trial-level regressor values, the estimate for studied items was different than zero. This showed that the later EEG activity indexed the trial-to-trial variability in drift rate for studied items. Our results provide strong evidence that only a single EEG component reflects evidence being used in the recegnition decision process.
近期关于知觉决策的研究表明，尽管有两个不同的神经成分可区分实验条件（例如，你看到的是一张脸还是一辆车），但只有一个成分跟踪引导决策过程的证据。在记忆文献中，通过脑电图测量的额中央诱发电位（始于350毫秒，似乎跟踪熟悉度）与在600毫秒达到峰值的顶叶晚期诱发电位（跟踪回忆）之间存在区别。在此，我们将单试次回归分析（类似于多变量模式分析，MVPA）和扩散决策建模应用于来自两个识别记忆实验的脑电图和行为数据，以测试这两个成分是否对识别决策过程有贡献。回归分析仅涉及一个项目是否被研究过，并未涉及行为数据的任何运用。只有脑电图的晚期活动能区分被研究过的项目和未被研究过的项目，在每个测试项目开始后约600毫秒达到峰值，该活动预测了从行为选择和反应时间得出的扩散模型漂移率（但仅针对被研究过的项目）。当漂移率成为试次水平回归值的线性函数时，对被研究项目的估计不为零。这表明，脑电图的晚期活动为被研究项目的漂移率在试次间的变异性提供了指标。我们的结果提供了强有力的证据，即只有单一的脑电图成分反映了识别决策过程中所使用的证据。
