Neurocomputation and Neuroimaging Unit, Department of Education and Psychology, Freie Universität Berlin, Habelschwerdter Allee 45, 14195, Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, Philippstr. 13, 10115, Berlin, Germany.
Neurocomputation and Neuroimaging Unit, Department of Education and Psychology, Freie Universität Berlin, Habelschwerdter Allee 45, 14195, Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, Philippstr. 13, 10115, Berlin, Germany.
Neuroimage. 2019 Jun;193:57-66. doi: 10.1016/j.neuroimage.2019.02.071. Epub 2019 Mar 5.
The study of perceptual decision making has made significant progress owing to major contributions from two experimental paradigms: the sequential vibrotactile frequency comparison task for the somatosensory domain requiring working memory, and the random-dot motion task in the visual domain requiring evidence accumulation over time. On the one hand, electrophysiological recordings in nonhuman primates and humans have identified changes in firing rates and power modulations of beta band oscillations with the vibrotactile frequencies held in working memory, as well as with the mental operation required for decision making. On the other hand, firing rates and centro-parietal potentials were found to increase to a fixed level at the time of responding during the random-dot motion task, possibly reflecting an underlying evidence accumulation mechanism until a decision threshold is met. Here, to bridge these two paradigms, we presented two visual random-dot motion stimuli in a sequential comparison task while recording EEG from human volunteers. We identified a modulation of prefrontal beta band power that scaled with the level of dot motion coherence of the first stimulus during a short retention interval. Furthermore, beta power in premotor areas was modulated by participants' choices approximately 700 ms before responses were given via button press. At the same time, dot motion patches of the second stimulus evoked a pattern of broadband centro-parietal signal build-up till responses were made, whose peak varied with trial difficulty. Hence, we show that known modulations of beta power during working memory and decision making extend from the vibrotactile to the visual domain and provide support for the notion of evidence accumulation as an unconfined decision-making mechanism generalizing over distinct decision types.
由于两个实验范式的重大贡献，感觉决策的研究取得了重大进展：用于需要工作记忆的躯体感觉域的顺序振动频率比较任务，以及用于随时间积累证据的视觉域中的随机点运动任务。一方面，非人类灵长类动物和人类的电生理记录已经确定了在振动频率保持在工作记忆中的情况下，β波段振荡的放电率和功率调制发生变化，以及进行决策所需的心理操作。另一方面，在随机点运动任务中，在响应时发现放电率和中央顶叶电位增加到固定水平，这可能反映了一种潜在的证据积累机制，直到达到决策阈值。在这里，为了弥合这两个范式，我们在记录人类志愿者的脑电图的同时，在顺序比较任务中呈现了两个视觉随机点运动刺激。我们确定了在前额叶β波段功率的调制，该调制与第一个刺激的点运动相干性水平在短的保留间隔期间成比例。此外，在参与者通过按钮按下给出响应之前大约 700ms，运动前区域的β功率被参与者的选择所调制。同时，第二个刺激的点运动斑块引发了一种宽带中央顶叶信号的累积模式，直到做出响应，其峰值随试验难度而变化。因此，我们表明，在工作记忆和决策过程中β功率的已知调制从振动触觉扩展到视觉领域，并为证据积累作为一种普遍适用于不同决策类型的无限制决策机制的概念提供了支持。
