Probabilistic learning is a fundamental cognitive ability that extracts and represents regularities of our environment enabling predictive processing during perception and acquisition of perceptual, motor, cognitive, and social skills. Previous studies show competition between neural networks related to executive function/working memory vs. probabilistic learning. Theta synchronization has been associated with the former while desynchronization with the latter in correlational studies. In the present paper our aim was to test causal relationship between fronto-parietal midline theta synchronization and probabilistic learning with non-invasive transcranial alternating current (tACS) stimulation. We hypothesize that theta synchronization disrupts probabilistic learning performance by modulating the competitive relationship. Twenty-six young adults performed the Alternating Serial Reaction Time (ASRT) task to assess probabilistic learning in two sessions that took place one week apart. Stimulation was applied in a double-blind cross-over within-subject design with an active theta tACS and a sham stimulation in a counter-balanced order between participants. Sinusoidal current was administered with 1 mA peak-to-peak intensity throughout the task (approximately 20 min) for the active stimulation and 30 s for the sham. We did not find an effect of fronto-parietal midline theta tACS on probabilistic learning comparing performance during active and sham stimulation. To influence probabilistic learning, we suggest applying higher current intensity and stimulation parameters more precisely aligned to endogenous brain activity for future studies.

概率学习是一种基本的认知能力，它提取和代表我们环境的规律，在感知和获得感知、运动、认知和社交技能的过程中实现预测处理。先前的研究表明，与执行功能/工作记忆相关的神经网络与概率学习之间存在竞争。Theta 同步与前者相关，而在相关研究中与后者不同步。在本文中，我们的目的是通过非侵入性经颅交流电 (tACS) 刺激测试额顶叶中线 theta 同步与概率学习之间的因果关系。我们假设 theta 同步通过调节竞争关系来破坏概率学习性能。26 名年轻人执行交替连续反应时间 (ASRT) 任务，以在相隔一周的两次会议中评估概率学习。在双盲交叉受试者内设计中应用刺激，在参与者之间以平衡顺序进行主动 theta tACS 和假刺激。在整个任务中（大约 20 分钟），正弦电流以 1 mA 的峰峰值强度管理，用于主动刺激，30 秒用于假手术。我们没有发现额顶叶中线 theta tACS 对概率学习的影响，比较主动和假刺激期间的表现。为了影响概率学习，我们建议将更高的电流强度和刺激参数更精确地与内源性大脑活动对齐，以供未来研究。