Presurgical brain mapping of language processing with fMRI: state of the art and tendencies

Abstract

Presurgical brain mapping of language-eloquent cortex aims to minimize its injury during neurosurgery in patients with brain tumors and drug-resistant epilepsy, and thereby, to preserve their quality of life. Two main goals of language mapping are to identify the localization and lateralization of brain regions involved in language. Gold standards for them are the intraoperative mapping and Wada test, respectively; however, due to some limitations of these techniques, non-invasive preliminary language mapping becomes reasonable. During the last years, fMRI has been widely applied for such purposes. Our literature review focuses on innovations and actual tendencies which spread in the field of language mapping via fMRI in the last decade. State-of-the-art knowledge on brain organization of language, which underpins brain mapping of language processing via fMRI, is briefly described in the article. Contemporary studies of fMRI validity in localization and lateralization of language brain regions are considered. Strategies of presurgical language mapping, such as application of tractography in addition to fMRI, combined analysis of fMRI tasks as well as resting-state fMRI are also discussed. Well-established fMRI tasks for brain mapping of language production and comprehension, as well as new experimental developments in this field, are listed and described.