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- M. Stetter and
K. Obermayer. Simulation of Scanning Laser techniques for optical imaging
of blood-related intrinsic signals.
.
J. Opt. Soc. Am. A, 16:58-70, 1999.
(FTP Gzipped PostScript, 46 pages, 98 kb)
Optical Imaging of intrinsic signals detects neural activation
patterns by taking video images of the local activity-related changes in the
light intensity reflected from neural tissue (intrinsic signals). At red
light (605nm), these signals are mainly caused by local variations of the
tissue absorption following deoxygenation of blood. In this work, we
characterize the image generation process during Optical Imaging by Monte
Carlo simulations of light propagation through a homogeneous model tissue
equipped with a local absorber. Conventional video-imaging and Scanning Laser
imaging are compared to each other. We find that, compared to video imaging,
Scanning Laser techniques drastically increase both the contrast and the
lateral resolution of optical recordings. Also, the maximum depth up to which
the signals can be detected, is increased by roughly a factor of 2 using
Scanning Laser Optical Imaging. Further, the radial profile of the diffuse
reflectance pattern for each pixel is subject to changes which correlate with
the depth of the absorber within the tissue. We suggest a detection geometry
for the online measurement of these radial profiles, which can be realized by
modifying a standard Scanning Laser Ophthalmoscope.
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