Sandrini Marco, Brambilla Michela, Manenti Rosa, Rosini Sandra, Cohen Leonardo G, Cotelli Maria
Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda, MD, USA ; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of Health Sciences Bethesda, MD, USA.
Neuropsychology Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli Brescia, Italy.
Front Aging Neurosci. 2014 Oct 20;6:289. doi: 10.3389/fnagi.2014.00289. eCollection 2014.
Memory consolidation is a dynamic process. Reactivation of consolidated memories by a reminder triggers reconsolidation, a time-limited period during which existing memories can be modified (i.e., weakened or strengthened). Episodic memory refers to our ability to recall specific past events about what happened, including where and when. Difficulties in this form of long-term memory commonly occur in healthy aging. Because episodic memory is critical for daily life functioning, the development of effective interventions to reduce memory loss in elderly individuals is of great importance. Previous studies in young adults showed that the dorsolateral prefrontal cortex (DLPFC) plays a causal role in strengthening of verbal episodic memories through reconsolidation. The aim of the present study was to explore the extent to which facilitatory transcranial direct current stimulation (anodal tDCS) over the left DLPFC would strengthen existing episodic memories through reconsolidation in elderly individuals. On Day 1, older adults learned a list of 20 words. On Day 2 (24 h later), they received a reminder or not, and after 10 min tDCS was applied over the left DLPFC. Memory recall was tested on Day 3 (48 h later) and Day 30 (1 month later). Surprisingly, anodal tDCS over the left DLPFC (i.e., with or without the reminder) strengthened existing verbal episodic memories and reduced forgetting compared to sham stimulation. These results provide a framework for testing the hypothesis that facilitatory tDCS of left DLPFC might strengthen existing episodic memories and reduce memory loss in older adults with amnestic mild cognitive impairment.
记忆巩固是一个动态过程。通过提示重新激活已巩固的记忆会触发重新巩固，这是一个有限的时间段，在此期间现有的记忆可以被修改（即减弱或增强）。情景记忆指的是我们回忆特定过去事件（包括发生了什么、地点和时间）的能力。这种形式的长期记忆困难在健康老龄化过程中很常见。由于情景记忆对日常生活功能至关重要，因此开发有效的干预措施以减少老年人的记忆丧失具有重要意义。先前针对年轻人的研究表明，背外侧前额叶皮层（DLPFC）在通过重新巩固来增强言语情景记忆方面起着因果作用。本研究的目的是探讨对左侧DLPFC进行促进性经颅直流电刺激（阳极tDCS）在多大程度上会通过重新巩固来增强老年人现有的情景记忆。在第1天，老年人学习了一份包含20个单词的列表。在第2天（24小时后），他们接受或未接受提示，10分钟后对左侧DLPFC施加tDCS。在第3天（48小时后）和第30天（1个月后）测试记忆回忆。令人惊讶的是，与假刺激相比，对左侧DLPFC进行阳极tDCS（即无论有无提示）都增强了现有的言语情景记忆并减少了遗忘。这些结果为检验以下假设提供了一个框架，即对左侧DLPFC进行促进性tDCS可能会增强老年人现有的情景记忆并减少遗忘性轻度认知障碍老年人的记忆丧失。
