Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford Centre for Human Brain Activity (OHBA) University Department of Psychiatry Warneford Hospital, Oxford, United Kingdom.
Department of Experimental Psychology, University of Oxford, Anna Watts Building, Radcliffe Observatory Quarter, Oxford, United Kingdom.
Elife. 2023 Oct 26;12:e82823. doi: 10.7554/eLife.82823.
During perceptual decision-making tasks, centroparietal electroencephalographic (EEG) potentials report an evidence accumulation-to-bound process that is time locked to trial onset. However, decisions in real-world environments are rarely confined to discrete trials; they instead unfold continuously, with accumulation of time-varying evidence being recency-weighted towards its immediate past. The neural mechanisms supporting recency-weighted continuous decision-making remain unclear. Here, we use a novel continuous task design to study how the centroparietal positivity (CPP) adapts to different environments that place different constraints on evidence accumulation. We show that adaptations in evidence weighting to these different environments are reflected in changes in the CPP. The CPP becomes more sensitive to fluctuations in sensory evidence when large shifts in evidence are less frequent, and the potential is primarily sensitive to fluctuations in decision-relevant (not decision-irrelevant) sensory input. A complementary triphasic component over occipito-parietal cortex encodes the sum of recently accumulated sensory evidence, and its magnitude covaries with parameters describing how different individuals integrate sensory evidence over time. A computational model based on leaky evidence accumulation suggests that these findings can be accounted for by a shift in decision threshold between different environments, which is also reflected in the magnitude of pre-decision EEG activity. Our findings reveal how adaptations in EEG responses reflect flexibility in evidence accumulation to the statistics of dynamic sensory environments.
在感知决策任务中，中央顶叶脑电图（EEG）电位报告了与试验开始时间锁定的证据积累到限制的过程。然而，现实环境中的决策很少局限于离散的试验；相反，它们是连续展开的，随着时间变化的证据的积累被最近的过去重新加权。支持最近加权连续决策的神经机制仍不清楚。在这里，我们使用一种新的连续任务设计来研究中央顶叶正波（CPP）如何适应对证据积累施加不同限制的不同环境。我们表明，对这些不同环境的证据加权的适应反映在 CPP 的变化中。当较大的证据变化不那么频繁时，CPP 对感官证据波动的敏感性增加，并且该电位主要对与决策相关（而非决策无关）的感官输入的波动敏感。枕顶皮层上的补充三相成分编码最近积累的感官证据的总和，其幅度与描述不同个体如何随时间整合感官证据的参数相关。基于泄漏证据积累的计算模型表明，这些发现可以通过不同环境之间决策阈值的变化来解释，这也反映在决策前 EEG 活动的幅度上。我们的研究结果揭示了 EEG 反应的适应如何反映对动态感官环境统计数据的证据积累的灵活性。
