Neural responses to human voice and hemisphere dominance for lexical-semantic processing--an fMRI study

• Published in: Methods of information in medicine Vol. 46; no. 2; p. 247
• Main Authors: Koeda, M, Takahashi, H, Yahata, N, Matsuura, M, Asai, K, Okubo, Y, Tanaka, H
• Format: Journal Article
• Language: English
• Published: Germany 2007
• Subjects: Adult; Brain Mapping; Cerebral Cortex - physiology; Cognition - physiology; Dominance, Cerebral - physiology; Female; Humans; Language; Magnetic Resonance Imaging; Male; Semantics; Signal Processing, Computer-Assisted; Surveys and Questionnaires; Voice - physiology
• ISSN: 0026-1270
• DOI: 10.1055/s-0038-1625416

In our previous functional magnetic resonance imaging (fMRI) study, we determined that there was distinct left hemispheric dominance for lexical-semantic processing without the influence of human voice perception in right-handed healthy subjects. However, the degree of right-handedness in the right-handed subjects ranged from 52 to 100 according to the Edinburgh Handedness Inventory (EHI) score. In the present study, we aimed to clarify the correlation between the degree of right-handedness and language dominance in the fronto-temporo-parietal cortices by examining cerebral activation for lexical-semantic processing.
Twenty-seven normal right-handed healthy subjects were scanned by fMRI while listening to sentences (SEN), reverse sentences (rSEN), and identifiable non-vocal sounds (SND). Fronto-temporo-parietal activation was observed in the left hemisphere under the SEN - rSEN contrast, which included lexical-semantic processing without the influence of human voice perception. Laterality Index was calculated as LI = (L - R)/(L + R) x 100, L: left, R: right.
Laterality Index in the fronto-temporo-parietal cortices did not correlate with the degree of right-handedness in EHI score.
The present study indicated that the degree of right-handedness from 52 to 100 in EHI score had no effect on the degree of left hemispheric dominance for lexical-semantic processing in right-handed healthy subjects.