Hyperspectral optical tomography of intrinsic signals in the rat cortex

Soren D. Konecky; Robert H. Wilson; Nathan A. Hagen; Amaan Mazhar; Tomasz S. Tkaczyk; Ron D. Frostig; Bruce J. Tromberg

doi:10.1117/1.NPh.2.4.045003

12 November 2015 Hyperspectral optical tomography of intrinsic signals in the rat cortex

Soren D. Konecky, Robert H. Wilson, Nathan A. Hagen, Amaan Mazhar, Tomasz S. Tkaczyk, Ron D. Frostig, Bruce J. Tromberg

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Neurophotonics, Vol. 2, Issue 4, 045003 (November 2015). https://doi.org/10.1117/1.NPh.2.4.045003

Abstract

We introduce a tomographic approach for three-dimensional imaging of evoked hemodynamic activity, using broadband illumination and diffuse optical tomography (DOT) image reconstruction. Changes in diffuse reflectance in the rat somatosensory cortex due to stimulation of a single whisker were imaged at a frame rate of 5 Hz using a hyperspectral image mapping spectrometer. In each frame, images in 38 wavelength bands from 484 to 652 nm were acquired simultaneously. For data analysis, we developed a hyperspectral DOT algorithm that used the Rytov approximation to quantify changes in tissue concentration of oxyhemoglobin (ctHbO₂) and deoxyhemoglobin (ctHb) in three dimensions. Using this algorithm, the maximum changes in ctHbO₂ and ctHb were found to occur at 0.29±0.02 and 0.66±0.04 mm beneath the surface of the cortex, respectively. Rytov tomographic reconstructions revealed maximal spatially localized increases and decreases in ctHbO₂ and ctHb of 321±53 and 555±96 nM, respectively, with these maximum changes occurring at 4±0.2 s poststimulus. The localized optical signals from the Rytov approximation were greater than those from modified Beer–Lambert, likely due in part to the inability of planar reflectance to account for partial volume effects.

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Soren D. Konecky, Robert H. Wilson, Nathan A. Hagen, Amaan Mazhar, Tomasz S. Tkaczyk, Ron D. Frostig, and Bruce J. Tromberg "Hyperspectral optical tomography of intrinsic signals in the rat cortex," Neurophotonics 2(4), 045003 (12 November 2015). https://doi.org/10.1117/1.NPh.2.4.045003

Published: 12 November 2015

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