title: Functional near-infrared spectroscopy study on primary motor and somatosensory cortex response to biting and finger clenching.
abstract: The purpose of this study was to compare the influence of biting and finger clenching intensity on the concentration of oxygenated hemoglobin (OxyHb) in regional cerebral blood flow (rCBF) as an indicator of brain activity in the primary motor (MI) and somatosensory (SI) cortices. Functional near-infrared spectroscopy (fNIRS) was used in 8 healthy subjects. Subjects were required to do biting (bite) and finger clenching (fclench) at 20, 50 and 80% of maximum force. To minimize the effect of temporal muscle activity on the working side of the jaw, the fNIRS probes were positioned contralaterally, in the left temporal region. Activation of MI and SI cortices with bite and fclench was noted in all subjects, irrespective of the intensity of bite and fclench. A significant increase was observed in OxyHb in MI and SI between 20% and both 50 and 80% intensity. In MI cortex, OxyHb showed a significant increase between 80% and both 20 and 50% fclench intensity. The results suggest that intensity of bite and fclench influences activation levels in MI and SI. Further, an activation was more obvious with bite than fclench.
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College, Nihon University School of Medicine, Tokyo, Japan. sibusawa@tdc.ac.jp
authors.forename: Mami
authors.initials: M
authors.lastname: Shibusawa
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Takeda
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nakajima
authors.forename: Handa
authors.initials: H
authors.lastname: Jun
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sekiguchi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishigami
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sakatani
mesh_terms: D000328:Adult; D001732:Bite Force; D005385:Fingers / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000098:blood supply / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D013003:Somatosensory Cortex / Q000098:blood supply / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*