A Simulation Study of Light Propagation in the Spinal Cord for Optogenetic Surface Stimulation

Shih Yin Chang, Satoshi Nishikawa, Masaki Sekino, Hiroshi Onodera, Yasuo Kuniyoshi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

For utilizing optogenetics in neuroscience research, a proper setup is necessary, which delivers sufficient light to target cells and minimizes unexpected side effects caused by light exposure. In this study, we were interested in the area of influence of optical surface stimulation on a spinal cord tissue. We built a 3D spinal cord structure of rat and utilized the Monte-Carlo methods to simulate the light transport in it. We first evaluated light propagation in homogeneous nervous tissue models. For a 10-mW, 470-nm light source, light intensity of 1 mW=mm2 was detected at depths of 1:14 and 1:77 mm in white and grey matter, respectively. This indicated a narrower spreading pattern of light in the white matter than in the grey matter. Since the grey matter, which contains the somatosensory pathways, is an important target of spinal cord stimulation, we focused on investigating how much light could reach this area in a multi-layered structure. The results showed that when an optical fiber was positioned in the center line of the spinal cord dorsal surface, most of the light energy was absorbed before reaching the grey matter. In contrast, when we put the fiber on a lateral position, 0:8mm away from the central line, relatively sufficient light intensity could be detected deep into the lamina 5 area. The experimental results obtained herein suggest that tissue type and the position of stimulation could greatly affect the area of influence of light stimulation in a 3D spinal cord. It is important to consider the location of the interested neural pathways and plan a proper stimulation site before conducting optogenetic surface stimulation of the spinal cord.

Original languageEnglish
Title of host publication2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2019
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages6872-6875
Number of pages4
ISBN (Electronic)9781538613115
DOIs
Publication statusPublished - Jul 2019
Externally publishedYes
Event41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2019 - Berlin, Germany
Duration: Jul 23 2019Jul 27 2019

Publication series

NameProceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
ISSN (Print)1557-170X

Conference

Conference41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2019
CountryGermany
CityBerlin
Period7/23/197/27/19

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

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