Anisotropic light scattering from myelinated axons in the spinal cord
| Autor: | Robert P. Bonin, Daniel Côté, Jean M. Deschenes, Laurent Goetz, Jimena Perez-Sanchez, Yves De Koninck, Damon DePaoli, Alicja Gasecka, Mohamed Bahdine, Martin Parent |
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| Rok vydání: | 2020 |
| Předmět: |
Paper
optical properties Neuroscience (miscellaneous) Optogenetics 01 natural sciences Light scattering 010309 optics White matter 03 medical and health sciences Myelin 0302 clinical medicine 0103 physical sciences medicine Radiology Nuclear Medicine and imaging tissue optics optogenetics Anisotropy Monte Carlo Physics Radiological and Ultrasound Technology Scattering spinal cord Spinal cord Research Papers myelin medicine.anatomical_structure Peripheral nervous system 030217 neurology & neurosurgery Biomedical engineering |
| Zdroj: | Neurophotonics |
| ISSN: | 2329-423X |
| DOI: | 10.1117/1.nph.7.1.015011 |
| Popis: | Optogenetics has become an integral tool for studying and dissecting the neural circuitries of the brain using optical control. Recently, it has also begun to be used in the investigation of the spinal cord and peripheral nervous system. However, information on these regions' optical properties is sparse. Moreover, there is a lack of data on the dependence of light propagation with respect to neural tissue organization and orientation. This information is important for effective simulations and optogenetic planning, particularly in the spinal cord where the myelinated axons are highly organized. To this end, we report experimental measurements for the scattering coefficient, validated with three different methods in both the longitudinal and radial directions of multiple mammalian spinal cords. In our analysis, we find that there is indeed a directional dependence of photon propagation when interacting with organized myelinated axons. Specifically, light propagating perpendicular to myelinated axons in the white matter of the spinal cord produced a measured reduced scattering coefficient ( μ s ' ) of 3.52 ± 0.1 mm - 1 , and light that was propagated along the myelinated axons in the white matter produced a measured μ s ' of 1.57 ± 0.03 mm - 1 , across the various species considered. This 50% decrease in scattering power along the myelinated axons is observed with three different measurement strategies (integrating spheres, observed transmittance, and punch-through method). Furthermore, this directional dependence in scattering power and overall light attenuation did not occur in the gray matter regions where the myelin organization is nearly random. The acquired information will be integral in preparing future light-transport simulations and in overall optogenetic planning in both the spinal cord and the brain. |
| Databáze: | OpenAIRE |
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