Blagovechtchenski Evgeny, Gnedykh Daria, Kurmakaeva Diana, Mkrtychian Nadezhda, Kostromina Svetlana, Shtyrov Yury
Laboratory of Behavioural Neurodynamics, St. Petersburg State University;
Laboratory of Behavioural Neurodynamics, St. Petersburg State University.
J Vis Exp. 2019 Jul 13(149). doi: 10.3791/59159.
Language is a highly important yet poorly understood function of the human brain. While studies of brain activation patterns during language comprehension are abundant, what is often critically missing is causal evidence of brain areas' involvement in a particular linguistic function, not least due to the unique human nature of this ability and a shortage of neurophysiological tools to study causal relationships in the human brain noninvasively. Recent years have seen a rapid rise in the use of transcranial direct current stimulation (tDCS) of the human brain, an easy, inexpensive and safe noninvasive technique that can modulate the state of the stimulated brain area (putatively by shifting excitation/inhibition thresholds), enabling a study of its particular contribution to specific functions. While mostly focusing on motor control, the use of tDCS is becoming more widespread in both basic and clinical research on higher cognitive functions, language included, but the procedures for its application remain variable. Here, we describe the use of tDCS in a psycholinguistic word-learning experiment. We present the techniques and procedures for application of cathodal and anodal stimulation of core language areas of Broca and Wernicke in the left hemisphere of the human brain, describe the procedures of creating balanced sets of psycholinguistic stimuli, a controlled yet naturalistic learning regime, and a comprehensive set of techniques to assess the learning outcomes and tDCS effects. As an example of tDCS application, we show that cathodal stimulation of Wernicke's area prior to a learning session can impact word learning efficiency. This impact is both present immediately after learning and, importantly, preserved over longer time after the physical effects of stimulation wear off, suggesting that tDCS can have long-term influence on linguistic storage and representations in the human brain.
语言是人类大脑一项极其重要却又鲜为人知的功能。虽然关于语言理解过程中大脑激活模式的研究丰富多样，但常常严重缺失的是大脑区域参与特定语言功能的因果证据，这主要归因于这种能力独特的人类特性以及缺乏用于无创研究人类大脑因果关系的神经生理学工具。近年来，经颅直流电刺激（tDCS）在人类大脑研究中的应用迅速增加，这是一种简便、廉价且安全的无创技术，能够调节受刺激脑区的状态（推测是通过改变兴奋/抑制阈值），从而得以研究该脑区对特定功能的具体贡献。虽然tDCS大多聚焦于运动控制，但在包括语言在内的高级认知功能的基础研究和临床研究中，其应用正变得越来越广泛，不过其应用程序仍存在差异。在此，我们描述了tDCS在一项心理语言学单词学习实验中的应用。我们介绍了在人类大脑左半球对布洛卡区和韦尼克区等核心语言区域进行阴极和阳极刺激的应用技术及程序，描述了创建平衡的心理语言学刺激集的程序、一种可控且自然主义的学习模式，以及一套全面的评估学习成果和tDCS效果的技术。作为tDCS应用的一个例子，我们表明在学习 session 之前对韦尼克区进行阴极刺激会影响单词学习效率。这种影响在学习后立即出现，重要的是，在刺激的物理效应消退后的较长时间内仍然存在，这表明tDCS可能对人类大脑中的语言存储和表征产生长期影响。 （注：原文中“session”未明确具体含义，直接保留英文）
