A Neurolinguistic Investigation of Emotional Prosody and Verbal Components of Speech

Abstract

Emotional prosody has a key role implication of timbre component, mood sense, and prosodic content. For this reason, it serves a highly important function for sense, the meaning to be reflected, and ability to provide effective communication. Due to its crucial role in verbal communication, it has a critical relationship within many disciplines such as linguistics, computer sciences, medicine, etc. Consequently, the knowledge of how the prosody sequence works in the brain will contribute to both language development and foreign language teaching as well as clinical evaluation of individuals with verbal communication difficulty. From this point of view, the current study takes an interdisciplinary perspective to address the investigation of brain localization of emotional prosody and verbal components of speech. In accordance with this purpose, the fNIRS technique was used. fNIRS has recently become popular as an emerging optical brain imaging technique for studying human brain. However, it is still not widespread compared to other neuroimaging techniques. This study was conducted on both 20 healthy native speakers of Turkish and English. Participants were recorded by using fNIRS while performing emotional prosody production and auditory stimulus tasks to measure the brain activation. Our results showed superior temporal gyrus, middle temporal gyrus, which includes primary and secondary auditory cortex, and superior temporal cortex, which comprises of temporal sulcus, were strongly activated by prosodies irrespective of emotional valence. Our findings also demonstrated left inferior frontal gyrus which comprises of pars triangularis; (Broadmann Area 45) and the frontal eye field (Broadmann Area 8) were significantly activated for happy, angry, and fearful prosodies.