Szalárdy Orsolya, Tóth Brigitta, Farkas Dávid, György Erika, Winkler István
Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
Institute of Behavioural Sciences, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
Front Psychol. 2019 Apr 9;10:786. doi: 10.3389/fpsyg.2019.00786. eCollection 2019.
Human listeners can follow the voice of one speaker while several others are talking at the same time. This process requires segregating the speech streams from each other and continuously directing attention to the target stream. We investigated the functional brain networks underlying this ability. Two speech streams were presented simultaneously to participants, who followed one of them and detected targets within it (target stream). The loudness of the distractor speech stream varied on five levels: moderately softer, slightly softer, equal, slightly louder, or moderately louder than the attended. Performance measures showed that the most demanding task was the moderately softer distractors condition, which indicates that a softer distractor speech may receive more covert attention than louder distractors and, therefore, they require more cognitive resources. EEG-based measurement of functional connectivity between various brain regions revealed frequency-band specific networks: (1) energetic masking (comparing the louder distractor conditions with the equal loudness condition) was predominantly associated with stronger connectivity between the frontal and temporal regions at the lower alpha (8-10 Hz) and gamma (30-70 Hz) bands; (2) informational masking (comparing the softer distractor conditions with the equal loudness condition) was associated with a distributed network between parietal, frontal, and temporal regions at the theta (4-8 Hz) and beta (13-30 Hz) bands. These results suggest the presence of distinct cognitive and neural processes for solving the interference from energetic vs. informational masking.
人类听众能够在其他几个人同时说话时，跟随其中一个人的声音。这个过程需要将语音流彼此分离，并持续将注意力导向目标语音流。我们研究了这种能力背后的功能性脑网络。向参与者同时呈现两个语音流，他们跟随其中一个语音流并检测其中的目标（目标语音流）。干扰语音流的响度有五个级别：比被关注的语音流适度更柔和、略柔和、相等、略响亮或适度响亮。性能指标表明，要求最高的任务是适度更柔和的干扰条件，这表明较柔和的干扰语音流可能比较响亮的干扰语音流受到更多的隐蔽注意力，因此，它们需要更多的认知资源。基于脑电图对不同脑区之间功能连接的测量揭示了特定频段的网络：(1) 能量掩蔽（将较响亮的干扰条件与响度相等的条件进行比较）主要与较低阿尔法（8 - 10赫兹）和伽马（30 - 70赫兹）频段的额叶和颞叶区域之间更强的连接相关；(2) 信息掩蔽（将较柔和的干扰条件与响度相等的条件进行比较）与顶叶、额叶和颞叶区域之间在西塔（4 - 8赫兹）和贝塔（13 - 30赫兹）频段的分布式网络相关。这些结果表明存在不同的认知和神经过程来解决来自能量掩蔽与信息掩蔽的干扰。
