Application of Functional Magnetic Resonance Imaging in Neurolinguistics: A Systematic Review

Abstract

Purpose: This paper aims to review the recent linguistic research carried out with the help of fMRI.
Materials and Methods: We performed a comprehensive search on ProQuest and Scopus search engines using keywords: "functional MRI", "fMRI", and "linguistics", "phonetics", "semantics", and their synonyms, yielding to a total of 343 articles. We included 23 articles based on full-text review which conducted original research on different aspects of language processing using fMRI. Studies regarding applied linguistics, as well as studies using subjects with any neuropsychological disorders, were excluded.
Results: Included studies were categorized according to the language areas they investigated, including phonetics and phonological processing; semantics; and syntax. The results show that the auditory cortex of both hemispheres is responsible for phonological comprehension of language at the first level, followed by left dominant processing of suprasegmental language in the superior temporal gyrus and the inferior frontal cortices and the supplementary motor area. During semantic processing of the language, lexical entry takes place in the medial temporal lobe and the hippocampus, while sentential semantic aspects of the language are predominantly processed in the left anterior temporal cortex. The BA 44 area is the major active region during syntax processing.
Conclusion: The experimental methods in studying language such as fMRI and other neurolinguistics techniques could provide scientific evidence for proving theoretical assumption. Besides, results of such researches can help other scientific developments such as brain mapping and pre-surgical planning.