Brambilla Michela, Manenti Rosa, Ferrari Clarissa, Cotelli Maria
Neuropsychology Unit, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
Neuropsychology Unit, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
Behav Brain Res. 2015 Oct 15;293:125-33. doi: 10.1016/j.bbr.2015.07.037. Epub 2015 Jul 19.
Episodic memory is a cognitive function that appears more susceptible than others to the effects of aging. The main aim of this study is to investigate if the magnitude of functional hemispheric lateralization during episodic memory test was positively correlated with memory performance, proving the presence of a beneficial pattern of neural processing in high-performing older adults but not in low-performing participants. We have applied anodal transcranial Direct Current Stimulation (tDCS) or sham stimulation over left and right hemisphere in a group of young subjects and in high-performing and low-performing older participants during an experimental verbal episodic memory task. Remarkably, young individuals and high-performing older adults exhibited similar performances on episodic memory tasks and both groups showed symmetrical recruitment of left and right areas during memory retrieval. In contrast, low-performing older adults, who obtained lower scores on the memory tasks, demonstrated a greater engagement of the left hemisphere during verbal memory task. Furthermore, structural equation model was performed for analyzing the interrelations between the index of interhemispheric asymmetry and several neuropsychological domains. We found that the bilateral engagement of dorsolateral prefrontal cortex and parietal cortex regions had a direct correlation with memory and executive functions evaluated as latent constructs. These findings drew attention to brain maintenance hypothesis. The potential of neurostimulation in cognitive enhancement is particularly promising to prevent memory loss during aging.
情景记忆是一种认知功能，相较于其他功能，它似乎更容易受到衰老的影响。本研究的主要目的是调查在情景记忆测试期间，功能性半球偏侧化的程度是否与记忆表现呈正相关，以证明在表现良好的老年人而非表现较差的参与者中存在一种有益的神经加工模式。在一项实验性言语情景记忆任务中，我们对一组年轻受试者以及表现良好和表现较差的老年参与者的左、右半球施加了阳极经颅直流电刺激（tDCS）或假刺激。值得注意的是，年轻人和表现良好的老年人在情景记忆任务上表现出相似的成绩，并且两组在记忆检索过程中均显示出左、右区域的对称激活。相比之下，在记忆任务中得分较低的表现较差的老年人在言语记忆任务期间表现出左半球的更大参与度。此外，我们进行了结构方程模型分析，以研究半球不对称指数与几个神经心理学领域之间的相互关系。我们发现，背外侧前额叶皮层和顶叶皮层区域的双侧参与与作为潜在结构评估的记忆和执行功能直接相关。这些发现引起了对大脑维持假说的关注。神经刺激在认知增强方面的潜力对于预防衰老过程中的记忆丧失特别有前景。
