Cross-language differences in the brain network subserving intelligible speech

Abstract

How is language processed in the brain by native speakers of different languages? Is there one brain system for all languages or are different languages subserved by different brain systems? The first view emphasizes commonality, whereas the second emphasizes specificity. We investigated the cortical dynamics involved in processing two very diverse languages: a tonal language (Chinese) and a nontonal language (English). We used functional MRI and dynamic causal modeling analysis to compute and compare brain network models exhaustively with all possible connections among nodes of language regions in temporal and frontal cortex and found that the information flow from the posterior to anterior portions of the temporal cortex was commonly shared by Chinese and English speakers during speech comprehension, whereas the inferior frontal gyrus received neural signals from the left posterior portion of the temporal cortex in English speakers and from the bilateral anterior portion of the temporal cortex in Chinese speakers. Our results revealed that, although speech processing is largely carried out in the common left hemisphere classical language areas (Broca's and Wernicke's areas) and anterior temporal cortex, speech comprehension across different language groups depends on how these brain regions interact with each other. Moreover, the right anterior temporal cortex, which is crucial for tone processing, is equally important as its left homolog, the left anterior temporal cortex, in modulating the cortical dynamics in tone language comprehension. The current study pinpoints the importance of the bilateral anterior temporal cortex in language comprehension that is downplayed or even ignored by popular contemporary models of speech comprehension.speech perception | tonal language | functional MRI | cortical dynamics T he brain of a newborn discriminates the various phonemic contrasts used in different languages (1) by recruiting distributed cortical regions (2); by 6-10 mo, it is preferentially tuned to the phonemes in native speech that they have been exposed to (3, 4). In adult humans, the key neural nodes that subserve speech comprehension are located in the superior temporal cortex (5, 6) and the inferior frontal cortex (7). Do these regions interact in different ways depending on the type of language that is being processed? Little is known about how information flows among these critical language nodes in native speakers of different languages.As one of the unique capacities of the human brain (8), the nature of compositional languages and their neural mechanisms have been the interests of scientific research for decades. There are more than 7,000 different spoken languages in the world today used for communication. By exploring the brain networks subserving universal properties across languages and specific differences within different languages, such research helps address the essential questions in neurolinguistics such as the constitution of knowledge of language, as well as how it is acquired (9). Although ...

Neuroanatomical Correlates of Perceived Usability

“…A one-sample t-test was applied to determine group-level activation for intelligibility effect. This process was similar to previous works [26,29].…”

Comprehending auditory speech: previous and potential contributions of functional MRI

“…In a DCM analysis, they found that the best model to explain the interactivity of these three sites involved auditory inputs driving posterior STS, with the intelligibility of speech modulating feed-forward connectivity from there to the other two sites. A more recent study has replicated this evidence for feed-forward connectivity between posterior and anterior sections of the STS, for both tonal and non-tonal languages (Ge et al, 2015).…”

“…In a DCM analysis, they found that the best model to explain the interactivity of these three sites involved auditory inputs driving posterior STS, with the intelligibility of speech modulating feed-forward connectivity from there to the other two sites. A more recent study has replicated this evidence for feed-forward connectivity between posterior and anterior sections of the STS, for both tonal and non-tonal languages (Ge et al, 2015).In sum, the work of the last ten years, with support from emerging techniques including MVPA and DCM, indicates important contributions for both posterior and anterior temporal cortex in speech comprehension. Evidence suggests that distributed, sparse neural codes support perception, and these patterns extend across anterior and posterior temporal cortex and into early auditory regions.…”

Development of the Intrinsic Language Network in Preschool Children from Ages 3 to 5 Years

“…In this analysis, four ROIs were selected based on a previous language study [39]. These regions indicated brain activations for speech intelligibility effect (intelligible > unintelligible) in the Chinese group.…”

“…Fifteen rs-fMRI data sets in each age group were acquired while children were in a natural sleep state. Intrinsic connectivity analysis was conducted with four language-related regions of interest (ROIs), including the left aSTG, left pSTG, right aSTG and left IFG, which had been shown to be activated in adult Chinese native speakers and chosen as ROIs in dynamic causal modeling [39]. Expecting to detect age-related changes at the network level, here, we firstly explored the development of intrinsic connectivity in the language network based on these selected ROIs.…”