An easy-to-implement, non-invasive head restraint method for monkey fMRI
Reiji Tanaka,
Kei Watanabe,
Takafumi Suzuki,
Kae Nakamura,
Masaharu Yasuda,
Hiroshi Ban,
Ken-ichi Okada,
Shigeru Kitazawa
Affiliations
Reiji Tanaka
Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan; Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
Kei Watanabe
Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan; Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka 565-0871, Japan; Corresponding author at: Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan.
Takafumi Suzuki
Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka 565-0871, Japan
Kae Nakamura
Department of Physiology, Kansai Medical University, Osaka 573-1010, Japan
Masaharu Yasuda
Department of Physiology, Kansai Medical University, Osaka 573-1010, Japan
Hiroshi Ban
Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka 565-0871, Japan
Ken-ichi Okada
School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
Shigeru Kitazawa
Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan; Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka 565-0871, Japan
Functional magnetic resonance imaging (fMRI) in behaving monkeys has a strong potential to bridge the gap between human neuroimaging and primate neurophysiology. In monkey fMRI, to restrain head movements, researchers usually surgically implant a plastic head-post on the skull. Although time-proven to be effective, this technique could create burdens for animals, including a risk of infection and discomfort. Furthermore, the presence of extraneous objects on the skull, such as bone screws and dental cement, adversely affects signals near the cortical surface. These side effects are undesirable in terms of both the practical aspect of efficient data collection and the spirit of “refinement” from the 3R's. Here, we demonstrate that a completely non-invasive fMRI scan in awake monkeys is possible by using a plastic head mask made to fit the skull of individual animals. In all of the three monkeys tested, longitudinal, quantitative assessment of head movements showed that the plastic mask has effectively suppressed head movements, and we were able to obtain reliable retinotopic BOLD signals in a standard retinotopic mapping task. The present, easy-to-make plastic mask has a strong potential to simplify fMRI experiments in awake monkeys, while giving data that is as good as or even better quality than that obtained with the conventional head-post method.
