Cerebral Functional Response during Eyelid Opening/Closing with Bell’s Phenomenon and Volitional Vertical Eye Movements in Humans

Cerebral Functional Response during Eyelid Opening/Closing with Bell's Phenomenon and Volitional Vertical Eye Movements in Humans

YUKIHISA SUZUKI,^1,2,3 MOTOHIRO KIYOSAWA,^1,4 KIICHI ISHIWATA,^2,5 KEIICHI ODA^2,6 and KENJI ISHII²

¹Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
²Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
³Department of Ophthalmology, Japan Community Health Care Organization, Mishima General Hospital, Mishima, Shizuoka, Japan
⁴Kiyosawa Eye Clinic, Tokyo, Japan
5 Institute of Cyclotron and Drug Discovery Research, Southern Tohoku Research Institute for Neuroscience, Koriyama, Fikushima, Japan
⁶Department of Radiological Technology, Faculty of Health Sciences, Hokkaido University of Science, Sapporo, Hokkaido, Japan

Bell's phenomenon is a physiological phenomenon wherein the eye ball involuntarily rolls upward during eyelid closing. Although this phenomenon occurs in healthy individuals, the neural mechanism related to Bell's phenomenon has not yet been identified. We aimed to investigate the brain regions relevant to Bell's phenomenon and volitional eye movement using [¹⁵O] H₂O and positron emission tomography (PET). We measured regional cerebral blood flow (rCBF) in 8 normal subjects under 3 conditions: at rest with eyes closed, during opening and closing of the eyelids in response to sound stimuli (lid opening/closing), and during vertical movement of the eyes with lids closed in response to sound stimuli (volitional eye movement). The supplementary motor area (SMA) proper, right superior temporal gyrus, right insular cortex and left angular gyrus were activated during lid opening/closing. The right frontal eye field (FEF), pre-SMA, left primary motor area, right angular gyrus, and SMA proper were activated during volitional eye movement. The SMA proper was active during both tasks, while the FEF and pre-SMA were active during volitional eye movement, but not during eyelid opening/closing. A comparison of activation during volitional eye movements and lid opening/closing tasks revealed a relative increase in rCBF in the FEF. There were no areas that are activated in relation to Bell's phenomenon. In conclusion, activation in the FEF mainly occurs during volitional eye movement. Since Bell's phenomenon is a reflexive eye movement, the FEF is scarcely concerned in Bell's phenomenon.

keywords —— Keywords: Bell's phenomenon; frontal eye field; positron emission tomography; regional cerebral blood flow; volitional eye movement

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Tohoku J. Exp. Med., 2016, 240, 141-146

Correspondence: Yukihisa Suzuki, M.D., Ph.D., Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University Graduated School, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.

e-mail: suzuki@f8.dion.ne.jp