Tosun Tuğçe, Berkay Dilara, Sack Alexander T, Çakmak Yusuf Ö, Balcı Fuat
Koç University, Istanbul, Turkey.
University of Pennsylvania.
J Cogn Neurosci. 2017 Aug;29(8):1433-1444. doi: 10.1162/jocn_a_01134. Epub 2017 Apr 7.
Decisions are made based on the integration of available evidence. The noise in evidence accumulation leads to a particular speed-accuracy tradeoff in decision-making, which can be modulated and optimized by adaptive decision threshold setting. Given the effect of pre-SMA activity on striatal excitability, we hypothesized that the inhibition of pre-SMA would lead to higher decision thresholds and an increased accuracy bias. We used offline continuous theta burst stimulation to assess the effect of transient inhibition of the right pre-SMA on the decision processes in a free-response two-alternative forced-choice task within the drift diffusion model framework. Participants became more cautious and set higher decision thresholds following right pre-SMA inhibition compared with inhibition of the control site (vertex). Increased decision thresholds were accompanied by an accuracy bias with no effects on post-error choice behavior. Participants also exhibited higher drift rates as a result of pre-SMA inhibition compared with the vertex inhibition. These results, in line with the striatal theory of speed-accuracy tradeoff, provide evidence for the functional role of pre-SMA activity in decision threshold modulation. Our results also suggest that pre-SMA might be a part of the brain network associated with the sensory evidence integration.
决策是基于现有证据的整合做出的。证据积累过程中的噪声会导致决策中特定的速度-准确性权衡，这种权衡可以通过自适应决策阈值设置进行调节和优化。鉴于前辅助运动区（pre-SMA）活动对纹状体兴奋性的影响，我们假设抑制前辅助运动区会导致更高的决策阈值和增加的准确性偏差。我们使用离线连续theta爆发刺激，在漂移扩散模型框架内的自由反应二选一强制选择任务中，评估右侧前辅助运动区的短暂抑制对决策过程的影响。与抑制控制部位（头顶）相比，右侧前辅助运动区抑制后，参与者变得更加谨慎并设置了更高的决策阈值。决策阈值的提高伴随着准确性偏差，且对错误后选择行为没有影响。与头顶抑制相比，前辅助运动区抑制还导致参与者表现出更高的漂移率。这些结果与纹状体速度-准确性权衡理论一致，为前辅助运动区活动在决策阈值调节中的功能作用提供了证据。我们的结果还表明，前辅助运动区可能是与感觉证据整合相关的脑网络的一部分。
