Reward motivation and neurostimulation interact to improve working memory performance in healthy older adults: A simultaneous tDCS-fNIRS study
Reward motivation and neurostimulation interact to improve working memory performance in healthy older adults: A simultaneous tDCS-fNIRS study
复制标题
DOI：
10.1016/j.neuroimage.2019.116062
复制
发表时间：
2019-11-15
期刊：
影响因子：
5.7
通讯作者：
Vallesi, Antonino
中科院分区：
文献类型：
--
作者：
Di Rosa, Elisa;Brigadoi, Sabrina;Vallesi, Antonino
一些研究评估了经颅直流电刺激（tDCS）对健康老年人前额叶皮层（PFC）增强工作记忆（WM）表现的影响。然而，到目前为止获得的混合结果表明，为了更直接地检查tDCS的影响，需要同时进行脑成像。本研究采用连续多模态方法，利用功能性近红外光谱（fNIRS）来研究tDCS与奖励动机操纵的交互效应。21名老年人（平均年龄= 69.7岁，SD = 5.05）在左侧前额叶皮质（PFC）施加1.5 mA淋巴结tDCS/sham之前、期间和之后进行了实验性视觉空间WM任务。在刺激过程中，参与者在WM任务中每一次快速和正确的反应都会获得绩效奖励。在两组实验中，双侧额叶区、运动区和顶叶区的血流动力学活动都被记录了下来。认知功能和奖励敏感性也用标准方法进行评估。结果显示tDCS对WM性能和血流动力学活性均有显著影响。具体来说，在阳极tDCS期间和之后，WM任务的反应都更快，而在假控制条件下没有发现差异。然而，只有当考虑到个人的视觉空间WM能力时，这些影响才会出现。此外，在阳极tDCS期间和之后，在双侧PFC中观察到相对于假手术的血流动力学活性增加，而在运动区和顶叶区没有检测到tDCS的影响。这些结果为健康老年人在执行WM任务时PFC活动的tdcs依赖性功能变化提供了第一个证据。此外，他们强调了将奖励动机与前额叶阳极tDCS相结合的效用，作为提高低绩效健康老年人WM效率的潜在策略。
Several studies have evaluated the effect of anodal transcranial direct current stimulation (tDCS) over the prefrontal cortex (PFC) for the enhancement of working memory (WM) performance in healthy older adults. However, the mixed results obtained so far suggest the need for concurrent brain imaging, in order to more directly examine tDCS effects. The present study adopted a continuous multimodal approach utilizing functional near-infrared spectroscopy (fNIRS) to examine the interactive effects of tDCS combined with manipulations of reward motivation. Twenty-one older adults (mean age = 69.7 years; SD = 5.05) performed an experimental visuo-spatial WM task before, during and after the delivery of 1.5 mA anodal tDCS/sham over the left prefrontal cortex (PFC). During stimulation, participants received performance-contingent reward for every fast and correct response during the WM task. In both sessions, hemodynamic activity of the bilateral frontal, motor and parietal areas was recorded across the entire duration of the WM task. Cognitive functions and reward sensitivity were also assessed with standard measures. Results demonstrated a significant impact of tDCS on both WM performance and hemodynamic activity. Specifically, faster responses in the WM task were observed both during and after anodal tDCS, while no differences were found under sham control conditions. However, these effects emerged only when taking into account individual visuo-spatial WM capacity. Additionally, during and after the anodal tDCS, increased hemodynamic activity relative to sham was observed in the bilateral PFC, while no effects of tDCS were detected in the motor and parietal areas. These results provide the first evidence of tDCS-dependent functional changes in PFC activity in healthy older adults during the execution of a WM task. Moreover, they highlight the utility of combining reward motivation with prefrontal anodal tDCS, as a potential strategy to improve WM efficiency in low performing healthy older adults.