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.
Highlights
In rodent olfactory bulb (OB), odor-evoked functional map has been commonly investigated by optical intrinsic signal imaging (OISI) [1,2]
OISI has been used for investigation of functional map in rodent OB because OISI have advantages of lateral resolution and does not need any exogenous treatment
We proposed using functional optical coherence tomography (fOCT) to investigate functional map of rodent OB
Summary
In rodent olfactory bulb (OB), odor-evoked functional map has been commonly investigated by optical intrinsic signal imaging (OISI) [1,2]. Optical sectioning at different focus points with OISI was reported [11]. Even in such cases, it is difficult to increase z-axis spatial resolution to a few micrometers level. Apart from OISI, fMRI is a widely used functional brain imaging technique for obtaining functional map of OB [3,12]. FMRI does not support a few micrometers level of spatial resolution for both lateral and depth. As a way to overcome these difficulties, we propose the use of functional optical coherence tomography (fOCT) [13] for visualization of depth-resolved functional map of OB under high spatial resolutions
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have