School of Psychology, The University of Queensland, St Lucia, Queensland 4072, Australia
School of Psychology, The University of Queensland, St Lucia, Queensland 4072, Australia.
J Neurosci. 2023 Oct 18;43(42):7006-7015. doi: 10.1523/JNEUROSCI.1086-23.2023. Epub 2023 Sep 1.
The speed-accuracy trade-off (SAT), whereby faster decisions increase the likelihood of an error, reflects a cognitive strategy humans must engage in during the performance of almost all daily tasks. To date, computational modeling has implicated the latent decision variable of response caution (thresholds), the amount of evidence required for a decision to be made, in the SAT. Previous imaging has associated frontal regions, notably the left prefrontal cortex and the presupplementary motor area (pre-SMA), with the setting of such caution levels. In addition, causal brain stimulation studies, using transcranial direct current stimulation (tDCS), have indicated that while both of these regions are involved in the SAT, their role appears to be dissociable. tDCS efficacy to impact decision-making processes has previously been linked with neurochemical concentrations and cortical thickness of stimulated regions. However, to date, it is unknown whether these neurophysiological measures predict individual differences in the SAT, and brain stimulation effects on the SAT. Using ultra-high field (7T) imaging, here we report that instruction-based adjustments in caution are associated with both neurochemical excitability (the balance between GABA+ and glutamate) and cortical thickness across a range of frontal regions in both sexes. In addition, cortical thickness, but not neurochemical concentrations, was associated with the efficacy of left prefrontal and superior medial frontal cortex (SMFC) stimulation to modulate performance. Overall, our findings elucidate key neurophysiological predictors, frontal neural excitation, of individual differences in latent psychological processes and the efficacy of stimulation to modulate these. The speed-accuracy trade-off (SAT), faster decisions increase the likelihood of an error, reflects a cognitive strategy humans must engage in during most daily tasks. The SAT is often investigated by explicitly instructing participants to prioritize speed or accuracy when responding to stimuli. Using ultra-high field (7T) magnetic resonance imaging (MRI), we found that individual differences in the extent to which participants adjust their decision strategies with instruction related to neurochemical excitability (ratio of GABA+ to glutamate) and cortical thickness in the frontal cortex. Moreover, brain stimulation to the left prefrontal cortex and the superior medial frontal cortex (SMFC) modulated performance, with the efficacy specifically related to cortical thickness. This work sheds new light on the neurophysiological basis of decision strategies and brain stimulation.
速度-准确性权衡（SAT），即更快的决策增加出错的可能性，反映了人类在执行几乎所有日常任务时必须采用的认知策略。迄今为止，计算模型已经将潜在的决策变量反应谨慎性（阈值），即做出决策所需的证据量，纳入 SAT 中。先前的成像研究将额区，特别是左前额叶皮层和补充运动区（pre-SMA）与谨慎水平的设定联系起来。此外，使用经颅直流电刺激（tDCS）的因果脑刺激研究表明，尽管这两个区域都参与了 SAT，但它们的作用似乎是可分离的。tDCS 对决策过程的影响效能以前与刺激区域的神经化学浓度和皮质厚度有关。然而，到目前为止，尚不清楚这些神经生理学指标是否可以预测 SAT 中的个体差异以及 SAT 中大脑刺激的效果。使用超高场（7T）成像，我们在此报告，基于指令的谨慎调整与两性前额叶区域的神经化学兴奋性（GABA+与谷氨酸的平衡）和皮质厚度有关。此外，皮质厚度而不是神经化学浓度与左前额叶和上内侧额皮质（SMFC）刺激调节性能的效能有关。总体而言，我们的研究结果阐明了关键的神经生理学预测因子，即个体潜在心理过程差异和调节这些过程的刺激效能的前额神经兴奋。速度-准确性权衡（SAT），更快的决策增加出错的可能性，反映了人类在执行大多数日常任务时必须采用的认知策略。SAT 通常通过明确指示参与者在响应刺激时优先考虑速度或准确性来进行研究。使用超高场（7T）磁共振成像（MRI），我们发现参与者根据指令调整决策策略的程度与前额叶皮质的神经化学兴奋性（GABA+与谷氨酸的比率）和皮质厚度有关。此外，对左前额叶和上内侧额皮质（SMFC）的脑刺激调节了性能，其效能与皮质厚度具体相关。这项工作为决策策略和脑刺激的神经生理学基础提供了新的认识。
