Evaluation of cortical activation area responsible for changes in orofacial function: An fMRI study

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12470458
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 矯正・小児・社会系歯学
• Research Institution: Tokyo Medical and Dental University
• Principal Investigator: ONO Takashi Tokyo Med. Dent. Univ., Graduate School, Assistant Prof., 大学院・医歯学総合研究科, 助手 (30221857)
• Co-Investigator(Kenkyū-buntansha): HONDA Ei-ichi Tokyo Med. Dent. Univ., Dental Hospital, Lecturer, 歯学部・附属病院, 講師 (30192321)
• Project Period (FY): 2000 – 2001
• Keywords: fMRI / cortical activation / tongue movement / SPM99 / primary sensorimotor cortex / brain function / chewing-side preference

Research Abstract

Blood oxygenation level dependent (BOLD)-functional magnetic resonance imaging (fMRI) is known to be a noninvasive technique for studying human brain function. The purpose of this study, applying the above method to 8 normal right-handed volunteers, was to identify brain areas responsible for producing tongue movements and their relations with the individual chewing side preference. All subjects gave written informed consentand were studied with local ethical approval, and the chewing side preference was interviewed after the experiment. All subjects were trained, before the MR imaging, to perform tongue movements with visual feedback of electromyographic activities of orofacial muscles in order to minimize the artifacts onto the acquired images by motion of orofacial area. ASiemens Vision 1.5T MRI apparatus was used for image acquisition. The data were analyzed by SPM99. In the group analysis, marked increase of BOLD signals compared with the rest conditions was detected during tongue movements in primary sensorimotor cortices, supplementary motor area and cerebellum ; in all instances were these brain areas of both hemispheres activated upon all of protrusion, rignt and leftward tongue movements. By the individual-based analysis of BOLD signals during various tongue movements in 6 subjects with evident chewing side preference, the signal intensity of the primary sensorimotor cortex and the cerebellum tended to be greater in the contralateral and ipsilateral side of the chewing side preference, respectively. The results suggest that, in primary sensorimotor cortices responsible for tongue movements, there is a relationship between hemispheric dominance and chewing side preference across subjects.