Viejo-Sobera Raquel, Redolar-Ripoll Diego, Boixadós Mercè, Palaus Marc, Valero-Cabré Antoni, Marron Elena M
Cognitive NeuroLab, Faculty of Health Sciences, Universitat Oberta de CatalunyaBarcelona, Spain.
Laboratory for Neuropsychiatry and Neuromodulation, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical SchoolBoston, MA, United States.
Front Neurosci. 2017 Aug 18;11:462. doi: 10.3389/fnins.2017.00462. eCollection 2017.
Theta burst stimulation (TBS) protocols hold high promise in neuropsychological rehabilitation. Nevertheless, their ability to either decrease (continuous, cTBS) or increase (intermittent, iTBS) cortical excitability in areas other than the primary motor cortex, and their consistency modulating human behaviors with clinically relevant tasks remain to be fully established. The behavioral effects of TBS over the dorsolateral prefrontal cortex (dlPFC) are particularly interesting given its involvement in working memory (WM) and executive functions (EF), often impaired following frontal brain damage. We aimed to explore the ability of cTBS and iTBS to modulate WM and EF in healthy individuals, assessed with clinical neuropsychological tests (Digits Backward, 3-back task, Stroop Test, and Tower of Hanoi). To this end, 36 participants were assessed using the four tests 1 week prior to stimulation and immediately following a single session of either cTBS, iTBS, or sham TBS, delivered to the left dlPFC. No significant differences were found across stimulation conditions in any of the clinical tasks. Nonetheless, in some of them, active stimulation induced significant pre/post performance modulations, which were not found for the sham condition. More specifically, sham stimulation yielded improvements in the 3-back task and the Color, Color-Word, and Interference Score of the Stroop Test, an effect likely caused by task practice. Both, iTBS and cTBS, produced improvements in Digits Backward and impairments in 3-back task accuracy. Moreover, iTBS increased Interference Score in the Stroop Test in spite of the improved word reading and impaired color naming, whereas cTBS decreased the time required to complete the Tower of Hanoi. Differing from TBS outcomes reported for cortico-spinal measures on the primary motor cortex, our analyses did not reveal any of the expected performance differences across stimulation protocols. However, if one considers independently pre/post differences for each individual outcome measure and task, either one or both of the active protocols appeared to modulate WM and EF. We critically discuss the value, potential explanations, and some plausible interpretations for this set of subtle impacts of left dlPFC TBS in humans.
theta爆发刺激（TBS）方案在神经心理康复方面具有很高的前景。然而，它们在初级运动皮层以外的区域降低（连续，cTBS）或增加（间歇，iTBS）皮层兴奋性的能力，以及它们在临床相关任务中调节人类行为的一致性仍有待充分确定。鉴于背外侧前额叶皮层（dlPFC）参与工作记忆（WM）和执行功能（EF），而额叶脑损伤后这些功能常受损，TBS对dlPFC的行为影响尤其令人感兴趣。我们旨在通过临床神经心理测试（数字倒背、3-back任务、Stroop测试和河内塔测试）来探索cTBS和iTBS调节健康个体WM和EF的能力。为此，36名参与者在刺激前1周以及在对左侧dlPFC进行单次cTBS、iTBS或假TBS刺激后立即使用这四项测试进行评估。在任何临床任务中，各刺激条件之间均未发现显著差异。尽管如此，在其中一些任务中，主动刺激引起了显著的刺激前后表现调节，而假刺激条件下未发现这种情况。更具体地说，假刺激在3-back任务以及Stroop测试的颜色、颜色-单词和干扰得分方面产生了改善，这种效应可能是由任务练习引起的。iTBS和cTBS都使数字倒背得到改善，而3-back任务的准确性受损。此外，尽管单词阅读有所改善且颜色命名受损，但iTBS增加了Stroop测试中的干扰得分，而cTBS减少了完成河内塔所需的时间。与在初级运动皮层上进行的皮质脊髓测量所报告的TBS结果不同，我们的分析未揭示不同刺激方案之间任何预期的表现差异。然而，如果单独考虑每个个体结果测量和任务的刺激前后差异，一种或两种主动方案似乎都能调节WM和EF。我们批判性地讨论了左侧dlPFC TBS对人类这一系列微妙影响的价值、潜在解释和一些合理的解读。
