title: Functional optical coherence tomography of rat olfactory bulb with periodic odor stimulation.
abstract: In rodent olfactory bulb (OB), optical intrinsic signal imaging (OISI) is commonly used to investigate functional maps to odorant stimulations. However, in such studies, the spatial resolution in depth direction (z-axis) is lost because of the integration of light from different depths. To solve this problem, we propose functional optical coherence tomography (fOCT) with periodic stimulation and continuous recording. In fOCT experiments of in vivo rat OB, propionic acid and m-cresol were used as odor stimulus presentations. Such a periodic stimulation enabled us to detect the specific odor-responses from highly scattering brain tissue. Swept source OCT operating at a wavelength of 1334 nm and a frequency of 20 kHz, was employed with theoretical depth and lateral resolutions of 6.7 μm and 15.4 μm, respectively. We succeeded in visualizing 2D cross sectional fOCT map across the neural layer structure of OCT in vivo. The detected fOCT signals corresponded to a few glomeruli of the medial and lateral parts of dorsal OB. We also obtained 3D fOCT maps, which upon integration across z-axis agreed well with OISI results. We expect such an approach to open a window for investigating and possibly addressing toward inter/intra-layer connections at high resolutions in the future.
authors.affiliation: Laboratory for Integrative Neural Systems, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-city, Saitama, 351-0198, Japan; Course of Health Science, Graduate school of Medicine, Osaka University, 1-7 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Department of Food Life Sciences, Faculty of Food Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma, 374-0193, Japan.
authors.forename: Uma Maheswari
authors.initials: UM
authors.lastname: Rajagopalan
authors.affiliation: Laboratory for Integrative Neural Systems, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-city, Saitama, 351-0198, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Nakamichi
authors.affiliation: Department of Anatomy and Neurobiology School of Medicine University of California, Irvine Hall Room 112, California 92697, USA.
authors.forename: Kei M
authors.initials: KM
authors.lastname: Igarashi
authors.affiliation: Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-08570, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kadono
authors.affiliation: Laboratory for Integrative Neural Systems, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-city, Saitama, 351-0198, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Tanifuji
keywords: (070.2615) Frequency filtering; (170.2655) Functional monitoring and imaging; (170.3010) Image reconstruction techniques; (170.3880) Medical and biological imaging; (170.4500) Optical coherence tomography; (170.5380) Physiology; (170.6900) Three-dimensional microscopy; (170.6935) Tissue characterization