Intelligent Systems Research Centre, School of Computing, Engineering and Intelligent Systems, Ulster University, Magee Campus, Derry∼Londonderry, United Kingdom.
School of Psychology, National University of Ireland Galway, Galway, Ireland.
PLoS Comput Biol. 2020 Feb 3;16(2):e1007149. doi: 10.1371/journal.pcbi.1007149. eCollection 2020 Feb.
Decisions are occasionally accompanied by changes-of-mind. While considered a hallmark of cognitive flexibility, the mechanisms underlying changes-of-mind remain elusive. Previous studies on perceptual decision making have focused on changes-of-mind that are primarily driven by the accumulation of additional noisy sensory evidence after the initial decision. In a motion discrimination task, we demonstrate that changes-of-mind can occur even in the absence of additional evidence after the initial decision. Unlike previous studies of changes-of-mind, the majority of changes-of-mind in our experiment occurred in trials with prolonged initial response times. This suggests a distinct mechanism underlying such changes. Using a neural circuit model of decision uncertainty and change-of-mind behaviour, we demonstrate that this phenomenon is associated with top-down signals mediated by an uncertainty-monitoring neural population. Such a mechanism is consistent with recent neurophysiological evidence showing a link between changes-of-mind and elevated top-down neural activity. Our model explains the long response times associated with changes-of-mind through high decision uncertainty levels in such trials, and accounts for the observed motor response trajectories. Overall, our work provides a computational framework that explains changes-of-mind in the absence of new post-decision evidence.
决策偶尔伴随着改变主意。虽然改变主意被认为是认知灵活性的标志，但改变主意的机制仍然难以捉摸。以前关于感知决策的研究主要集中在初始决策后，主要由额外的嘈杂感官证据积累驱动的改变主意上。在一项运动辨别任务中，我们证明即使在初始决策后没有额外证据的情况下，改变主意也会发生。与之前改变主意的研究不同，我们实验中的大多数改变主意发生在初始反应时间延长的试验中。这表明存在一种不同的改变主意机制。使用决策不确定性和改变主意行为的神经回路模型，我们证明这种现象与不确定性监测神经群体介导的自上而下信号有关。这种机制与最近的神经生理学证据一致，表明改变主意与升高的自上而下的神经活动之间存在联系。我们的模型通过此类试验中较高的决策不确定性水平解释了与改变主意相关的长反应时间，并解释了观察到的运动反应轨迹。总的来说，我们的工作提供了一个计算框架，解释了在没有新的决策后证据的情况下的改变主意。
