Processing numerosities relies on the innate capacity to understand and manipulate the number of items in a set, and to additional abilities such as inhibitory skills –which are known to be linked to brain oscillations in the alpha range. Whether these inhibitory skills are causally linked to numerosity processing and critical for it is unclear. To address this question, we used alpha-based brain stimulation (transcranial alternate current stimulation, tACS) to target inhibitory abilities in the context of numerosity discrimination. Twenty-nine young adults received bilateral tACS to the parietal lobe, a brain region critical for numerical processes. tACS at target (alpha, 10 Hz), control oscillation frequencies (theta, 4 Hz; beta, 22 Hz; sham, no stimulation), and control areas (bilateral frontal regions) was paired to an established numerosity paradigm that allows distinguishing between congruent and incongruent numerosity trials, the latter requiring to inhibit task-irrelevant information. Performance significantly and specifically worsened in incongruent numerosity trials following bilateral parietal alpha-tACS relative to sham and to the other stimulations used, possibly due to the desynchronization of parietal neuronal oscillations in the alpha range. No significant changes in performance were observed in parietal beta and theta-tACS, relative to sham, nor in frontal alpha-tACS. Likewise, there were no changes in performing congruent numerosity trials. We therefore concluded that parietal alpha oscillations are causally linked to inhibitory abilities, and reinforced the view that these abilities are intrinsic to numerosity discrimination.

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基于顶叶阿尔法的抑制能力与数字歧视有因果关系

处理数字依赖于理解和操纵一组物品数量的先天能力，以及抑制技能等附加能力——众所周知，这与阿尔法范围内的大脑振荡有关。这些抑制技能是否与数字处理存在因果关系以及是否对其至关重要尚不清楚。为了解决这个问题，我们使用基于阿尔法的脑刺激（经颅交流电刺激，tACS）来针对数字歧视背景下的抑制能力。 29 名年轻人接受了针对顶叶的双侧 tACS，顶叶是对数字处理至关重要的大脑区域。目标处的 tACS（α，10 Hz）、控制振荡频率（θ，4 Hz；β，22 Hz；假手术，无刺激）和控制区域（双侧额叶区域）与已建立的数值范式配对，允许区分一致的数值范式和不一致的数值试验，后者需要抑制与任务无关的信息。相对于假手术和使用的其他刺激，在双侧顶叶 α-tACS 后的不一致数值试验中，表现显着且特别恶化，这可能是由于 α 范围内顶叶神经元振荡的去同步。相对于假手术，在顶叶 β 和 θ-tACS 中没有观察到显着的性能变化，在额叶 α-tACS 中也没有观察到显着变化。同样，进行全等数值试验也没有变化。因此，我们得出结论，顶叶阿尔法振荡与抑制能力存在因果关系，并强化了这些能力是数字辨别所固有的观点。