Functionally integrated neural processing of linguistic and talker information: An event-related fMRI and ERP study.
Speech signals contain information of both linguistic content and a talker's voice. Conventionally, linguistic and talker processing are thought to be mediated by distinct neural systems in the left and right hemispheres respectively, but there is growing evidence that linguistic and talker processing interact in many ways. Previous studies suggest that talker-related vocal tract changes are processed integrally with phonetic changes in the bilateral posterior superior temporal gyrus/superior temporal sulcus (STG/STS), because the vocal tract parameter influences the perception of phonetic information. It is yet unclear whether the bilateral STG is also activated by the integral processing of another parameter - pitch, which influences the perception of lexical tone information and is related to talker differences in tone languages. In this study, we conducted separate functional magnetic resonance imaging (fMRI) and event-related potential (ERP) experiments to examine the spatial and temporal loci of interactions of lexical tone and talker-related pitch processing in Cantonese. We found that the STG was activated bilaterally during the processing of talker changes when listeners attended to lexical tone changes in the stimuli and during the processing of lexical tone changes when listeners attended to talker changes, suggesting that lexical tone and talker processing are functionally integrated in the bilateral STG. It extends the previous study, providing evidence for a general neural mechanism of integral phonetic and talker processing in the bilateral STG. The ERP results show interactions of lexical tone and talker processing 500-800ms after auditory word onset (a simultaneous posterior P3b and a frontal negativity). Moreover, there is some asymmetry in the interaction, such that unattended talker changes affect linguistic processing more than vice versa, which may be related to the ambiguity that talker changes cause in speech perception and/or attention bias to talker changes. Our findings have implications for understanding the neural encoding of linguistic and talker information.
Department of Chinese and Bilingual Studies, The Hong Kong Polytechnic University, Hong Kong, China; Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China. Electronic address: caicai.zhang@polyu.edu.hk.
Caicai
C
Zhang
Haskins Laboratories, New Haven, CT, USA; Department of Psychology, University of Connecticut, Storrs, CT, USA; Department of Linguistics, Yale University, New Haven, CT, USA.
Kenneth R
KR
Pugh
Haskins Laboratories, New Haven, CT, USA; Department of Linguistics, Yale University, New Haven, CT, USA.
W Einar
WE
Mencl
Haskins Laboratories, New Haven, CT, USA; Department of Psychology, University of Connecticut, Storrs, CT, USA.
Peter J
PJ
Molfese
Haskins Laboratories, New Haven, CT, USA.
Stephen J
SJ
Frost
Haskins Laboratories, New Haven, CT, USA; Department of Psychology, University of Connecticut, Storrs, CT, USA.
James S
JS
Magnuson
Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; CUHK-PKU-UST Joint Research Centre for Language and Human Complexity, The Chinese University of Hong Kong, Hong Kong, China; Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Hong Kong, China. Electronic address: gpeng@cuhk.edu.hk.
Gang
G
Peng
Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; CUHK-PKU-UST Joint Research Centre for Language and Human Complexity, The Chinese University of Hong Kong, Hong Kong, China; Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Hong Kong, China; Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, China.
William S-Y
WS
Wang
D000328:Adult; D001931:Brain Mapping; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010700:Phonetics; D010898:Pitch Perception / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
ERP; Lexical tones; Linguistic processing; Neural bases; Talker processing; fMRI