ISSN 0439-755X
CN 11-1911/B
主办:中国心理学会
   中国科学院心理研究所
出版:科学出版社

心理学报 ›› 2018, Vol. 50 ›› Issue (7): 727-738.doi: 10.3724/SP.J.1041.2018.00727

• 研究报告 • 上一篇    下一篇

右侧背外侧前额叶在视觉工作记忆中的因果性作用

王思思, 库逸轩()   

  1. 华东师范大学心理与认知科学学院, 上海 200062
  • 收稿日期:2017-07-03 出版日期:2018-07-15 发布日期:2018-05-29
  • 基金资助:
    * 国家社会科学基金重大项目(17ZDA323);上海市浦江人才计划(16PJC022);华东师范大学人文社会科学青年预研究项(2017ECNU-YYJ050)

The causal role of right dorsolateral prefrontal cortex in visual working memory

WANG Sisi, KU Yixuan()   

  1. School of Psychology and Cognitive Science, East China Normal University, Shanghai 200062, China
  • Received:2017-07-03 Online:2018-07-15 Published:2018-05-29

摘要:

以往的影像学研究表明右侧背外侧前额叶皮层(DLPFC)在视觉工作记忆中发挥重要作用, 然而缺乏因果性的证据。本研究旨在考察右侧DLPFC的激活与视觉工作记忆容量的因果关系, 并探讨这一关系受到记忆负荷的调节及其神经机制。被试接受经颅直流电刺激之后完成视觉工作记忆变化检测任务, 根据被试在虚假刺激情况下从负荷4到负荷6任务记忆容量的增量将被试分为低记忆增长潜力组(简称低潜力组)和高记忆增长潜力组(简称高潜力组), 结果发现正性电刺激右侧DLPFC相对于虚假电刺激显著提升了高潜力组被试在低记忆负荷(负荷4)下的记忆容量及其对应的提取阶段的脑电指标SPCN成分。表明右侧DLPFC在视觉工作记忆的提取阶段发挥重要的因果性作用; 正性经颅直流电刺激右侧DLPFC可使工作记忆容量高潜力被试获得更多的脑活动增益, 并导致更好的行为提升效果。

关键词: 视觉工作记忆, 经颅直流电刺激, 右侧背外侧前额叶皮层, SPCN, 记忆潜力

Abstract:

The right dorsolateral prefrontal cortex (DLPFC) plays an important role in working memory. Previous neuroimaging and neurophysiological studies have found sustained and elevated DLPFC activity during working memory delay period. Meanwhile, the right DLPFC has been suggested to be more dominant in visuospatial than verbal working memory. While the causal evidence for the relationship between the right DLPFC and visual working memory is still rare.

Transcranial direct current stimulation (tDCS) and EEG were combined to investigate the causal relationship between the right DLPFC and processes of visual working memory. Forty participants performed a color change detection task with memory load of 4 items (load-4) or 6 items (load-6) while their electroencephalography (EEG) was recorded. Before they performed the tasks, either 15 min of 1.5 mA transcranial direct current stimulation (tDCS) or 30 s of 1.5 mA sham stimulation (SHAM) was applied over the right DLPFC. The participants were divided into two groups according to their working memory capacity increment from load-4 to load-6 in the sham condition, the group who gained more increment (the high potential group) under the sham condition also benefit more from the anodal tDCS over the right DLPFC, while the other group (the low potential group) did not show such effects.

To further explore the neural mechanisms, N2pc and SPCN were compared between different conditions. N2pc did not show any stimulating effects or load effects for both low and high potential groups. In contrast, although SPCN did not show significant main effects of load or stimulation, or their interaction for the low potential group, SPCN did show main effects of stimulation for high potential group. The amplitude of SPCN after tDCS over the right DLPFC was significantly larger than that after the sham stimulation under load-4 condition, which coincided with the behavioral findings, and further suggested the role of the right DLPFC in representing the memory information during retrieval.

In sum, anodal tDCS over the right DLPFC promoted visual working memory capacity of those who had more cognitive potential from easier task (load-4) to harder task (load-6). The present study confirmed the causal role of the right DLPFC in representing the visual working memory information during the retrieval period.

Key words: visual working memory, tDCS, right DLPFC, SPCN, working memory potential

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