Department of Psychology, Koç University, Istanbul, Turkey; Research Center for Translational Medicine, Koç University, Istanbul, Turkey.
Research Center for Translational Medicine, Koç University, Istanbul, Turkey; Department of Psychiatry, Koç University, School of Medicine, Istanbul, Turkey.
Neuropsychologia. 2018 Jan 31;109:255-261. doi: 10.1016/j.neuropsychologia.2017.12.031. Epub 2017 Dec 20.
Many perceptual decisions are inevitably subject to the tradeoff between speed and accuracy of choices (SAT). Sequential sampling models attribute this ubiquitous relation to random noise in the sensory evidence accumulation process, and assume that SAT is adaptively modulated by altering the decision thresholds at which the level of integrated evidence should reach for making a choice. Although, neuroimaging studies have shown a relationship between right presupplementary motor area (pre-SMA) activity and threshold setting, only a limited number of brain stimulation studies aimed at establishing the causal link, results of which were inconsistent. Additionally, these studies were limited in scope as they only examined the effect of pre-SMA activity unidirectionally through experimentally inhibiting the neural activity in this region. The current study aims to investigate the predictions of the striatal theory of SAT by experimentally assessing the modulatory effect of right pre-SMA on threshold setting bi-directionally. To this end, we applied both offline inhibition and excitation to the right pre-SMA utilizing transcranial magnetic stimulation in a within-subjects design and tested participants on a Random Dot Motion Task. Decision thresholds were estimated using the Hierarchical Drift Diffusion Model. Findings of our planned comparisons showed that right pre-SMA inhibition leads to significantly higher, whereas right pre-SMA excitation leads to significantly lower thresholds without showing any effects on the evidence integration process itself.
许多感知决策不可避免地受到速度和准确性的权衡（SAT）的影响。序列采样模型将这种普遍存在的关系归因于感觉证据积累过程中的随机噪声，并假设 SAT 通过改变决策阈值来自适应地调节，即集成证据应该达到的水平以做出选择。尽管神经影像学研究表明右侧预备运动区（pre-SMA）活动与阈值设定之间存在关系，但旨在建立因果关系的脑刺激研究数量有限，结果不一致。此外，这些研究的范围有限，因为它们仅通过实验抑制该区域的神经活动来单向研究 pre-SMA 活动的影响。本研究旨在通过实验评估右 pre-SMA 对阈值设定的双向调制作用，来验证纹状体 SAT 理论的预测。为此，我们在一项被试内设计中利用经颅磁刺激对右 pre-SMA 进行离线抑制和兴奋，并在随机点运动任务上测试参与者。使用分层漂移扩散模型估计决策阈值。我们的计划比较结果表明，右 pre-SMA 抑制导致明显更高的阈值，而右 pre-SMA 兴奋导致明显更低的阈值，而对证据整合过程本身没有任何影响。
