Doshisha University, Kyotanabe-Shi, Kyoto, Japan.
Brain Behav. 2018 Oct;8(10):e01104. doi: 10.1002/brb3.1104. Epub 2018 Sep 5.
Many people spend a considerable amount of time performing intellectual activities within auditory environments that affect work efficiency. To investigate auditory environments that improve working efficiency, we investigated the relationship between brain activity and performance of the number memory task in environments with and without white noise using functional near-infrared spectroscopy (fNIRS).
Twenty-nine healthy subjects (aged 21.9 ± 1.4 years) performed the number memory task in both the white noise and silent environments. Cerebral blood flow changes during the task were measured using an ETG-7100 fNIRS system (Hitachi, Ltd., Tokyo, Japan). The psychological states of the subjects were also estimated by subjective ratings of the pleasantness of the auditory environment. Then, they were divided into three groups based on their task scores. The differences in the cerebral blood flow (CBF) changes, functional connection strength, and the subjects' feelings of pleasantness to the noise between the subject groups were analyzed and discussed.
The first group felt that the white noise was pleasant, which strengthened the bilateral functional connections between the brain regions related to the memory task. Therefore, the subjects' task performance improved in the white noise environment. Although the second group felt that the white noise was uncomfortable, the frontal regions related to attention control were more activated in the white noise environment to sustain the task performance in the noisy environment. The third group felt that the white noise was unpleasant, and their CBF decreased in that environment, which was associated with deteriorated task performance.
Task performance was closely related to the subjects' feelings of pleasantness to the noise. The results of the analysis of the CBF changes and functional connectivity suggested that the effects of the white noise on brain activity differed among the three groups.
许多人在影响工作效率的听觉环境中花费大量时间进行智力活动。为了研究改善工作效率的听觉环境，我们使用功能近红外光谱（fNIRS）研究了在有和没有白噪声的环境中，大脑活动与数字记忆任务表现之间的关系。
29 名健康受试者（年龄 21.9±1.4 岁）在白噪声和安静环境中均进行数字记忆任务。使用 ETG-7100 fNIRS 系统（日立公司，东京，日本）测量任务期间的脑血流变化。通过对听觉环境愉悦感的主观评价来估计受试者的心理状态。然后，根据他们的任务得分将他们分为三组。分析和讨论了不同组之间的脑血流（CBF）变化、功能连接强度和受试者对噪声的愉悦感的差异。
第一组认为白噪声令人愉悦，从而增强了与记忆任务相关的大脑区域之间的双侧功能连接。因此，在白噪声环境中，受试者的任务表现得到了改善。尽管第二组认为白噪声令人不适，但在白噪声环境中，与注意力控制相关的额叶区域更加活跃，以维持在嘈杂环境中的任务表现。第三组认为白噪声令人不愉快，并且在这种环境中他们的 CBF 下降，这与任务表现恶化有关。
任务表现与受试者对噪声的愉悦感密切相关。CBF 变化和功能连接分析的结果表明，白噪声对大脑活动的影响在三组之间存在差异。
