gms | German Medical Science

Objective: An increasing body of functional neuroanatomical evidence suggests that Chinese language processing requires brain areas distinct from those used when processing the English language. However, existing studies of Chinese language processing are limited to functional neuroimaging studies. Data gathered through intraoperative electrocortical stimulation of language cortex provide a unique opportunity for mapping the distribution and topographical organization of language. Our purpose is to establish the patterns of language in Chinese-speakers by using multimodality techniques.

Method: Intraoperative language mappings were obtained from 55 patients with gliomas. Positive sites associated with speech arrest, anomia, and alexia were categorized and used to generate cortical language maps. These maps were also compared with those obtained from task-based functional MRI (fMRI). In addition, by defining the positive sites as the seed regions, we computed the functional connectivity in 15 patients to generate the language networks.

Results: A total of 112 language sites were identified from a total of 1402 sites stimulated during a number counting task. Of these 112 sites, 78 (69.6%) were located in the ventral precentral gyrus (50.9%) and pars opercularis (18.7%), followed by 12 (10.7%) in the middle frontal gyrus, 13 (11.6%) in the pars triangularis, and 3 sites (2.7%) in the superior frontal gyrus. Stimulation at 33 of the 1030 sites during a picture-naming task resulted in anomia. Eight of the 925 sites were associated with stimulation-induced alexia during a Chinese word-reading task. Language maps were also generated from fMRI data of three different tasks (picture naming, verb generation, recitation) in 15 patients. Recitation activated the left ventral precentral and postventral gyrus. The tasks of picture naming and verb generation have the same patterns, that activations in left inferior frontal gyrus and posterior middle frontal gyrus were obviously detected. The language networks based on resting fMRI and stimulation sites demonstrated that the left inferior frontal gyrus, the ventral precentral and postcentral gyrus, the Wernicke’s area and superior parietal lobe were involved.

Conclusions: Our electrophysiological evidence suggests that the ventral precentral gyrus (ventral part of BA6) and the pars opercularis (BA44) play a critical role in speech production. Additionally, by comparing stimulation maps of Chinese and English-speakers, the left middle frontal gyrus may be unique to Chinese language processing, which was also supported by the task fMRI data. The resting language network generated from golden standard may display a more real pattern.