Department of Experimental Psychology, University of Groningen, 9712 TS Groningen, The Netherlands.
Cognitive Science Center Amsterdam, University of Amsterdam, 1018 VZ Amsterdam, The Netherlands.
Neuroimage. 2014 Aug 1;96:95-105. doi: 10.1016/j.neuroimage.2014.03.063. Epub 2014 Apr 1.
The contingent negative variation, a slow cortical potential, occurs when humans are warned by a stimulus about an upcoming task. The cognitive processes that give rise to this EEG potential are not yet well understood. To explain these processes, we adopt a recently developed theoretical framework from the area of perceptual decision-making. This framework assumes that the basal ganglia control the tradeoff between fast and accurate decision-making in the cortex. It suggests that an increase in cortical excitability serves to lower response caution, which results in faster but more error prone responding. We propose that the CNV reflects this increased cortical excitability. To test this hypothesis, we conducted an EEG experiment in which participants performed the random dot motion task either under speed or under accuracy stress. Our results show that trial-by-trial fluctuations in participants' response speed as well as model-based estimates of response caution correlated with single-trial CNV amplitude under conditions of speed but not accuracy stress. We conclude that the CNV might reflect adjustments of response caution, which serves to enhance quick decision-making.
当人类受到刺激警告即将进行某项任务时，就会产生一种称为负变的缓慢皮质电位。这种脑电图电位产生的认知过程尚未得到很好的理解。为了解释这些过程，我们采用了来自感知决策领域的一个新的理论框架。该框架假设基底神经节控制着大脑皮层中快速和准确决策之间的权衡。它表明皮质兴奋性的增加有助于降低反应谨慎性，从而导致更快但更易出错的反应。我们提出，CNV 反映了这种增加的皮质兴奋性。为了验证这一假设，我们进行了一项 EEG 实验，参与者在速度或准确性压力下执行随机点运动任务。我们的结果表明，在速度压力下，参与者的反应速度的逐次波动以及基于模型的反应谨慎性估计与单次 CNV 幅度相关，但在准确性压力下则不相关。我们得出结论，CNV 可能反映了反应谨慎性的调整，这有助于增强快速决策。
