title: High-Speed Video-Oculography for Measuring Three-Dimensional Rotation Vectors of Eye Movements in Mice.
abstract: BACKGROUND
  The mouse is the most commonly used animal model in biomedical research because of recent advances in molecular genetic techniques. Studies related to eye movement in mice are common in fields such as ophthalmology relating to vision, neuro-otology relating to the vestibulo-ocular reflex (VOR), neurology relating to the cerebellum's role in movement, and psychology relating to attention. Recording eye movements in mice, however, is technically difficult.
  
  
  METHODS
  We developed a new algorithm for analyzing the three-dimensional (3D) rotation vector of eye movement in mice using high-speed video-oculography (VOG). The algorithm made it possible to analyze the gain and phase of VOR using the eye's angular velocity around the axis of eye rotation.
  
  
  RESULTS
  When mice were rotated at 0.5 Hz and 2.5 Hz around the earth's vertical axis with their heads in a 30° nose-down position, the vertical components of their left eye movements were in phase with the horizontal components. The VOR gain was 0.42 at 0.5 Hz and 0.74 at 2.5 Hz, and the phase lead of the eye movement against the turntable was 16.1° at 0.5 Hz and 4.88° at 2.5 Hz.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first report of this algorithm being used to calculate a 3D rotation vector of eye movement in mice using high-speed VOG. We developed a technique for analyzing the 3D rotation vector of eye movements in mice with a high-speed infrared CCD camera. We concluded that the technique is suitable for analyzing eye movements in mice. We also include a C++ source code that can calculate the 3D rotation vectors of the eye position from two-dimensional coordinates of the pupil and the iris freckle in the image to this article.
authors.affiliation: Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Imai
authors.affiliation: Department of Otolaryngology, Suita Municipal Hospital, Osaka, Japan.
authors.forename: Yasumitsu
authors.initials: Y
authors.lastname: Takimoto
authors.affiliation: Department of Otorhinolaryngology - Head and Neck Surgery, Tokushima University Graduate School of Medicine, Tokushima, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Takeda
authors.affiliation: Department of Otorhinolaryngology - Head and Neck Surgery, Osaka General Medical Center, Osaka, Japan.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Uno
authors.affiliation: Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Inohara
authors.affiliation: Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Shimada
mesh_terms: D000818:Animals; D005133:Eye Movements / Q000502:physiology*; D021621:Imaging, Three-Dimensional; D008297:Male; D008810:Mice, Inbred C57BL; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology; D012399:Rotation; D014741:Video Recording