title: Development of a removable head fixation device for longitudinal behavioral and imaging studies in rats.
abstract: BACKGROUND
  In some behavioral neuroscience studies, an attachment is surgically fixed onto the head of an awake animal to allow the animal to perform learning tasks repeatedly in the same position in a task-training system. A recently developed task-training system enables operant conditioning of head-fixed rats within only a few days, and this system has been rigorously applied to record learning-associated neural activity using electrophysiological techniques. However, the head attachment of this device is made of metal and thus is not suitable for simultaneous brain imaging studies with X-ray computed tomography (CT), magnetic resonance imaging (MRI) or positron emission tomography (PET).
  
  
  METHODS
  We developed a novel head fixation device with a removable attachment to position the rat head precisely in both imaging and training devices across different sessions. The device consisted of a removable attachment, a clamp and a stage, all of which were made of PET/MRI compatible acrylic resin. We tested the usefulness of the device with (18)F-fluorodeoxyglucose (FDG) PET and CT.
  
  
  RESULTS
  The new device did not substantially affect (18)F-FDG PET images. Repositioning of the rat's head across sessions and experimenters was at a level of submillimeter accuracy.
  
  
  CONCLUSIONS
  The errors of radioactivity concentration of (18)F-FDG in the PET image were lower with the present attachment than with the conventional metal attachment. Repositioning accuracy was considerably improved compared with a visual inspection method.
  
  
  CONCLUSIONS
  The developed fixation device is useful for longitudinal behavioral and brain imaging studies in rats.
authors.affiliation: Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan; Department of Functional Brain Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. Electronic address: horiy@ncnp.go.jp.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hori
authors.affiliation: Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ogura
authors.affiliation: Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan; Department of Functional Brain Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ihara
authors.affiliation: Department of Medical Engineering, LMS Co. Ltd., Bunkyo-ku, Tokyo, Japan.
authors.forename: Tsunehisa
authors.initials: T
authors.lastname: Higashi
authors.affiliation: Department of Medical Engineering, LMS Co. Ltd., Bunkyo-ku, Tokyo, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tashiro
authors.affiliation: Department of Functional Brain Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Honda
authors.affiliation: Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan; Department of Functional Brain Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. Electronic address: hanakawa@ncnp.go.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hanakawa
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D004867:Equipment Design; D059907:Functional Neuroimaging / Q000379:methods*; D006257:Head; D007103:Immobilization / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging; D008297:Male; D049268:Positron-Emission Tomography; D051381:Rats; D020318:Rats, Long-Evans; D014057:Tomography, X-Ray Computed
keywords: Behavioral studies; Head fixation device; MRI; Operant learning; PET; Small animal