Song Fengxiang, Zhan Yi, Ford James C, Cai Dan-Chao, Fellows Abigail M, Shan Fei, Song Pengrui, Chen Guochao, Soli Sigfrid D, Shi Yuxin, Buckey Jay C
Department of Radiology, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.
Space Medicine Innovations Laboratory, Geisel School of Medicine at Dartmouth, Hanover, NH, United States.
Front Neurosci. 2020 Dec 17;14:614012. doi: 10.3389/fnins.2020.614012. eCollection 2020.
Previous studies have revealed increased frontal brain activation during speech comprehension in background noise. Few, however, used tonal languages. The normal pattern of brain activation during a challenging speech-in-nose task using a tonal language remains unclear. The Mandarin Hearing-in-Noise Test (HINT) is a well-established test for assessing the ability to interpret speech in background noise. The current study used Mandarin HINT (MHINT) sentences and functional magnetic resonance imaging (fMRI) to assess brain activation with MHINT sentences.
Thirty native Mandarin-speaking subjects with normal peripheral hearing were recruited. Functional MRI was performed while subjects were presented with either HINT "clear" sentences with low-level background noise [signal-to-noise ratio (SNR) = +3 dB] or "noisy" sentences with high-level background noise (SNR = -5 dB). Subjects were instructed to answer with a button press whether a visually presented target word was included in the sentence. Brain activation between noisy and clear sentences was compared. Activation in each condition was also compared to a resting, no sentence presentation, condition.
Noisy sentence comprehension showed increased activity in areas associated with tone processing and working memory, including the right superior and middle frontal gyri [Brodmann Areas (BAs) 46, 10]. Reduced activity with noisy sentences was seen in auditory, language, memory and somatosensory areas, including the bilateral superior and middle temporal gyri, left Heschl's gyrus (BAs 21, 22), right temporal pole (BA 38), bilateral amygdala-hippocampus junction, and parahippocampal gyrus (BAs 28, 35), left inferior parietal lobule extending to left postcentral gyrus (BAs 2, 40), and left putamen.
Increased frontal activation in the right hemisphere occurred when comprehending noisy spoken sentences in Mandarin. Compared to studies using non-tonal languages, this activation was strongly right-sided and involved subregions not previously reported. These findings may reflect additional effort in lexical tone perception in this tonal language. Additionally, this continuous fMRI protocol may offer a time-efficient way to assess group differences in brain activation with a challenging speech-in-noise task.
以往研究显示，在背景噪声中进行言语理解时额叶脑区激活增强。然而，很少有研究使用声调语言。使用声调语言进行具有挑战性的噪声中言语任务时，大脑激活的正常模式仍不清楚。汉语噪声中听力测试（HINT）是评估在背景噪声中理解言语能力的一项成熟测试。本研究使用汉语HINT（MHINT）句子和功能磁共振成像（fMRI）来评估MHINT句子引起的脑激活。
招募了30名外周听力正常的汉语母语者。在向受试者呈现带有低水平背景噪声的HINT“清晰”句子[信噪比（SNR）= +3 dB]或带有高水平背景噪声的“嘈杂”句子（SNR = -5 dB）时进行功能磁共振成像。受试者被指示通过按按钮回答视觉呈现的目标词是否包含在句子中。比较嘈杂句子和清晰句子之间的脑激活情况。还将每种情况下的激活与静息状态（即不呈现句子）进行比较。
嘈杂句子理解显示，与声调处理和工作记忆相关的脑区活动增加，包括右侧额上回和额中回[布罗德曼区（BA）46、10]。在听觉、语言、记忆和体感区域，包括双侧颞上回和颞中回、左侧颞横回（BA 21、22）、右侧颞极（BA 38）、双侧杏仁核 - 海马交界处、海马旁回（BA 28、35）、延伸至左侧中央后回的左侧顶下小叶（BA 2、40）以及左侧壳核，观察到嘈杂句子引起的活动减少。
在理解汉语嘈杂口语句子时，右半球额叶激活增强。与使用非声调语言的研究相比，这种激活强烈偏向右侧，且涉及以前未报道的亚区域。这些发现可能反映了在这种声调语言中词汇声调感知方面的额外努力。此外，这种连续的功能磁共振成像方案可能提供一种高效的方法，通过具有挑战性的噪声中言语任务来评估脑激活的组间差异。
