Khanmohammadi Roya, Inanlu Mehrnaz, Manesh Vahid Rafiee
Department of Physical Therapy, School of Rehabilitation Sciences, Tehran University of Medical Sciences, Tehran, Iran.
Department of Physical Therapy, School of Rehabilitation Sciences, Tehran University of Medical Sciences, Tehran, Iran.
Behav Brain Res. 2025 May 28;486:115571. doi: 10.1016/j.bbr.2025.115571. Epub 2025 Apr 1.
While regions like the primary motor cortex (M1), left dorsolateral prefrontal cortex (DLPFC), and cerebellum are linked to cognitive functions, it is unclear which offers the greatest cognitive benefit. This study aimed to assess the effects of high-definition transcranial direct current stimulation (HD-tDCS) on these regions, focusing on inhibitory control, cognitive flexibility, and working memory. This parallel, randomized, double-blinded, and controlled trial involved 80 older adults, randomly assigned to one of four groups: anodal stimulation of M1, left DLPFC, cerebellum, or sham. Inhibitory control was assessed using reaction time (RT) and rate-correct score (RCS) from a Go/No-Go task. Trail Making Test A (TMT-A) and B (TMT-B) measured processing speed and cognitive flexibility, while the backward digit span test evaluated working memory. All assessments were conducted pre- and post-stimulation. Notably, cerebellum stimulation significantly improved working memory (p = 0.010), whereas M1, DLPFC, and sham did not. Significant interaction effects emerged for TMT-A and TMT-B, with both M1 and DLPFC stimulation enhancing performance (TMT-A: p = 0.005, p = 0.025; TMT-B: p < 0.001, p = 0.045, respectively), while cerebellum and sham had no significant impact. Additionally, RT and RCS showed no significant effects. Anodal stimulation of M1 and DLPFC improved cognitive flexibility and processing speed, whereas cerebellum stimulation selectively enhanced working memory. However, inhibitory control did not improve, highlighting the need for further tailored interventions. These findings underscore distinct region-specific effects of tDCS on cognitive performance in older adults.
虽然像初级运动皮层（M1）、左侧背外侧前额叶皮层（DLPFC）和小脑等区域与认知功能相关，但尚不清楚哪个区域能带来最大的认知益处。本研究旨在评估高清经颅直流电刺激（HD-tDCS）对这些区域的影响，重点关注抑制控制、认知灵活性和工作记忆。这项平行、随机、双盲和对照试验涉及80名老年人，随机分为四组之一：M1、左侧DLPFC、小脑的阳极刺激组或假刺激组。使用Go/No-Go任务中的反应时间（RT）和正确率得分（RCS）评估抑制控制。连线测验A（TMT-A）和B（TMT-B）测量加工速度和认知灵活性，而倒背数字广度测试评估工作记忆。所有评估均在刺激前后进行。值得注意的是，小脑刺激显著改善了工作记忆（p = 0.010），而M1、DLPFC和假刺激组则没有。TMT-A和TMT-B出现了显著的交互作用，M1和DLPFC刺激均提高了表现（TMT-A：p = 0.005，p = 0.025；TMT-B：分别为p < 0.001，p = 0.045），而小脑和假刺激组没有显著影响。此外，RT和RCS没有显著影响。M1和DLPFC的阳极刺激改善了认知灵活性和加工速度，而小脑刺激选择性地增强了工作记忆。然而，抑制控制没有改善，这凸显了进一步定制干预措施的必要性。这些发现强调了tDCS对老年人认知表现具有不同的区域特异性影响。
