Frontotemporal effective connectivity revealed a language-general syntactic network for Mandarin Chinese

Human language is proposed to be hierarchically constructed according to syntactic information. Studies on languages with overt morphosyntactic markers (e.g., German) have found a key frontotemporal syntactic network that includes Broca's area (Brodmann Area, BA 44/45) and the posterior temporal cortex (pTC). Whether this syntactic network is language-general is still unspecified. Mandarin Chinese is a suggestive empirical test case, lacking morphosyntax and relying heavily on function words to guide syntactic hierarchy construction. By developing the jabberwocky sentence paradigm, we created sets of visually-presented Chinese structures formed by function words and pseudo-words (the structure condition), and contrasted the structures with comparable word lists (the word-list condition) in healthy Chinese-speaking adults in a functional magnetic resonance imaging (fMRI) experiment. Participants were required to identify the syntactic category of each structure by merging its constituents into syntactic hierarchies, guided by function words. Compared with the word-list condition, the structure condition (a) elicited higher involvement of left BA 44, and (b) recruited a language-general syntactic network as revealed by the effective connectivity between BA 44, precentral gyrus, and pTC. These findings specified the neural basis for Chinese syntax and further corroborated the unique human language faculty across languages in a neurobiologically ubiquitous fashion.