Common Brain Substrates Underlying Auditory Speech Priming and Perceived Spatial Separation

Junxian Wang; Jing Chen; Xiaodong Yang; Lei Liu; Chao Wu; Lingxi Lu; Liang Li; Yanhong Wu

doi:10.3389/fnins.2021.664985

Common Brain Substrates Underlying Auditory Speech Priming and Perceived Spatial Separation

Front Neurosci. 2021 Jun 17:15:664985. doi: 10.3389/fnins.2021.664985. eCollection 2021.

Authors

Junxian Wang¹, Jing Chen^{2

3}, Xiaodong Yang¹, Lei Liu¹, Chao Wu⁴, Lingxi Lu⁵, Liang Li^{1

3

6}, Yanhong Wu^{1

3}

Affiliations

¹ School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China.
² Department of Machine Intelligence, Peking University, Beijing, China.
³ Speech and Hearing Research Center, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, China.
⁴ School of Nursing, Peking University, Beijing, China.
⁵ Center for the Cognitive Science of Language, Beijing Language and Culture University, Beijing, China.
⁶ Beijing Institute for Brain Disorders, Beijing, China.

Abstract

Under a "cocktail party" environment, listeners can utilize prior knowledge of the content and voice of the target speech [i.e., auditory speech priming (ASP)] and perceived spatial separation to improve recognition of the target speech among masking speech. Previous studies suggest that these two unmasking cues are not processed independently. However, it is unclear whether the unmasking effects of these two cues are supported by common neural bases. In the current study, we aimed to first confirm that ASP and perceived spatial separation contribute to the improvement of speech recognition interactively in a multitalker condition and further investigate whether there exist intersectant brain substrates underlying both unmasking effects, by introducing these two unmasking cues in a unified paradigm and using functional magnetic resonance imaging. The results showed that neural activations by the unmasking effects of ASP and perceived separation partly overlapped in brain areas: the left pars triangularis (TriIFG) and orbitalis of the inferior frontal gyrus, left inferior parietal lobule, left supramarginal gyrus, and bilateral putamen, all of which are involved in the sensorimotor integration and the speech production. The activations of the left TriIFG were correlated with behavioral improvements caused by ASP and perceived separation. Meanwhile, ASP and perceived separation also enhanced the functional connectivity between the left IFG and brain areas related to the suppression of distractive speech signals: the anterior cingulate cortex and the left middle frontal gyrus, respectively. Therefore, these findings suggest that the motor representation of speech is important for both the unmasking effects of ASP and perceived separation and highlight the critical role of the left IFG in these unmasking effects in "cocktail party" environments.

Keywords: auditory speech priming; common brain substrate; perceived spatial separation; speech motor system; speech recognition; unmasking.