Enhancing novel word learning by focalized transcranial direct current stimulation

学习新单词的能力是发育和成人大脑语言习得的一个重要方面，已知在正常衰老和与年龄相关的疾病中会下降。由于在工作和休闲环境下的日常生活中，新单词学习具有很高的生态有效性和相关性，本项目将专门研究个性化、局灶性经颅直流电刺激（tDCS）增强这一过程的神经机制和预测因素。从长远来看，该项目的成果将有助于改善神经退行性疾病（如痴呆及其前体）或影响语言（再）学习的神经损伤（中风后失语症）患者的治疗。在研究单位（RU）更广泛的背景下，本研究是八个研究tDCS对跨功能域学习和记忆形成的影响的项目之一（项目1-8）和健康的人类寿命。这些经验项目所采用的高度系统和协调的方法将允许首次分析潜在的神经机制和行为刺激反应的预测因素，不仅在每个项目内，而且在不同的任务和功能领域（项目9）。目前的项目将提供关于tDCS如何调节言语情景记忆形成的独特信息，从而补充项目4 （PI Hartwigsen）对tDCS诱导的言语工作记忆增强的研究。项目1使用类似的学习范式来研究视觉空间情景记忆形成（PI Flöel），与项目1的结果进行比较，可以研究各自结果的领域特异性。总的来说，RU的实证项目的结果将增加我们目前对tdcs诱导的神经网络效应、它们的区域特异性、刺激效应的个体间变异机制以及由于实足年龄的潜在变化的理解。从方法学的角度来看，在这些项目中获得的数据将有助于优化和验证电流的生物物理模型（P9+10），从而推进tDCS在健康和疾病方面的未来实验和转化应用。

The ability to learn new words is a crucial aspect of language acquisition in the developing and adult brain and known to decline in normal aging and age-associated disease. Because of the high ecological validity and relevance of novel word learning for everyday life in work and leisure contexts, this project will specifically investigate the neural mechanisms and predictors underlying enhancement of this process by individualized, focal transcranial direct current stimulation (tDCS). In the long-run, outcomes of this project will contribute to improving treatment of patients with neurodegenerative diseases (e.g., dementia and its precursors) or neurological injury (post-stroke aphasia) affecting language (re-)learning. Within the broader context of the Research Unit (RU), the present study is one of eight projects investigating tDCS effects on learning and memory formation across functional domains (Projects 1-8) and the healthy human lifespan. The highly systematic and coordinated approach pursued by these empirical projects will allow for the first time analyzing the underlying neural mechanisms and predictors of behavioural stimulation response not only within each project, but also across the different tasks and functional domains (Project 9).The current project will contribute unique information on how tDCS modulates verbal episodic memory formation, thereby complementing the investigation of tDCS-induced enhancement of verbal working memory in Project 4 (PI Hartwigsen). Comparison with results obtained from Project 1, that uses a similar learning paradigm to investigate visuo-spatial episodic memory formation (PI Flöel), will allow to investigate domain specificity of the respective outcomes. Collectively, the results of the empirical projects of the RU will increase our current understanding of tDCS-induced neural network effects, their regional specificity, the mechanisms underlying inter-individual variability of stimulation effects, and potential changes due to chronological age. From a methodological point of view, data acquired in these projects will contribute to optimizing and validating biophysical models of current flow (in P9+10), thereby advancing future experimental and translational applications of tDCS in health and disease.