Chizari Mojtaba, Navi Keivan, Khosrowabadi Reza
Institute for Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran.
Sci Rep. 2025 May 5;15(1):15654. doi: 10.1038/s41598-025-00034-1.
Adaptive decision-making in uncertain environments requires balancing exploration and exploitation. Computational models distinguish between directed exploration, involving deliberate information-seeking, and random exploration, characterized by stochastic variability. The neural correlates of these strategies have been investigated in previous studies. However, while prior research implicates the dorsolateral prefrontal cortex (DLPFC) in random exploration, its underlying excitatory and inhibitory mechanisms remain unclear. Understanding these processes is essential for explaining how individuals adapt to a dynamic environment. To investigate this, we combined transcranial magnetic stimulation (TMS) with electroencephalography (EEG) to directly assess cortical excitatory and inhibitory functions. Twenty-five healthy participants completed the Horizon Task, a behavioral paradigm designed to dissociate directed and random exploration, and after the task, they received single-pulse TMS over the DLPFC. The TMS-evoked potentials (TEPs) N45, P60, and N100 were examined as neurophysiological markers of GABA, GABA, and glutamate activity. Results revealed a significant positive correlation between the N100 amplitude at the right DLPFC and random exploration, suggesting that GABA-mediated inhibition plays a key role in stochastic decision-making. Additionally, a correlation between the decision noise parameter in the logistic model and the N100 amplitude further validated this association. These findings highlight the importance of prefrontal inhibition in exploratory behavior and underscore the utility of TMS-EEG in uncovering the neural mechanisms underlying adaptive decision-making.
在不确定环境中的适应性决策需要平衡探索与利用。计算模型区分了有向探索（涉及刻意寻求信息）和随机探索（其特征为随机变异性）。此前的研究已对这些策略的神经关联进行了探究。然而，虽然先前的研究表明背外侧前额叶皮层（DLPFC）参与随机探索，但其潜在的兴奋性和抑制性机制仍不清楚。理解这些过程对于解释个体如何适应动态环境至关重要。为了对此进行研究，我们将经颅磁刺激（TMS）与脑电图（EEG）相结合，以直接评估皮层的兴奋性和抑制性功能。25名健康参与者完成了地平线任务，这是一种旨在区分有向探索和随机探索的行为范式，任务结束后，他们在DLPFC上接受了单脉冲TMS。TMS诱发的电位（TEPs）N45、P60和N100被作为GABA、GABA和谷氨酸活性的神经生理标志物进行检测。结果显示，右侧DLPFC处的N100波幅与随机探索之间存在显著正相关，这表明GABA介导的抑制在随机决策中起关键作用。此外，逻辑模型中的决策噪声参数与N100波幅之间的相关性进一步验证了这种关联。这些发现突出了前额叶抑制在探索行为中的重要性，并强调了TMS-EEG在揭示适应性决策背后神经机制方面的效用。
