Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA.
Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, MI 48105, USA.
Cereb Cortex. 2022 Nov 9;32(22):5230-5241. doi: 10.1093/cercor/bhac010.
Spatial navigation is essential for everyday life and relies on complex network-level interactions. Recent evidence suggests that transcranial direct current stimulation (tDCS) can influence the activity of large-scale functional brain networks. We characterized brain-wide changes in functional network segregation (i.e. the balance of within vs. between-network connectivity strength) induced by high-definition (HD) tDCS in older adults with mild cognitive impairment (MCI) during virtual spatial navigation. Twenty patients with MCI and 22 cognitively intact older adults (healthy controls-HC) underwent functional magnetic resonance imaging following two counterbalanced HD-tDCS sessions (one active, one sham) that targeted the right parietal cortex (center anode at P2) and delivered 2 mA for 20 min. Compared to HC, MCI patients showed lower brain-wide network segregation following sham HD-tDCS. However, following active HD-tDCS, MCI patients' network segregation increased to levels similar to those in HC, suggesting functional normalization. Follow-up analyses indicated that the increase in network segregation for MCI patients was driven by HD-tDCS effects on the "high-level"/association brain networks, in particular the dorsal-attention and default-mode networks. HD-tDCS over the right parietal cortex may normalize the segregation/integration balance of association networks during spatial navigation in MCI patients, highlighting its potential to restore brain activity in Alzheimer's disease.
空间导航对于日常生活至关重要，依赖于复杂的网络级相互作用。最近的证据表明，经颅直流电刺激（tDCS）可以影响大脑的大规模功能网络的活动。我们描述了在轻度认知障碍（MCI）老年人进行虚拟空间导航期间，使用高清晰度（HD）tDCS 诱导的功能网络分离（即，内部网络连接强度与外部网络连接强度之间的平衡）的全脑变化。 20 名 MCI 患者和 22 名认知正常的老年人（健康对照组-HC）在接受了两次平衡的 HD-tDCS 治疗（一次为主动，一次为假）后进行了功能磁共振成像，这些治疗靶向右顶叶皮层（P2 中心阳极）并施加 2 mA 电流 20 分钟。与 HC 相比，MCI 患者在接受假 HD-tDCS 后大脑全网络分离程度较低。但是，在进行主动 HD-tDCS 后，MCI 患者的网络分离度增加到与 HC 相似的水平，表明功能正常化。后续分析表明，MCI 患者的网络分离度增加是由 HD-tDCS 对“高级”/关联网络的影响驱动的，特别是背侧注意和默认模式网络。右顶叶皮层上的 HD-tDCS 可能会使 MCI 患者在空间导航期间的关联网络的分离/整合平衡正常化，突出了其在恢复阿尔茨海默氏病患者大脑活动方面的潜力。
