| 研究課題/領域番号 |
18F18807
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| 研究機関 | 総合研究大学院大学 |
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研究代表者 |
蟻川 謙太郎 総合研究大学院大学, 先導科学研究科, 教授 (20167232)
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| 研究分担者 |
ILIC MARKO 総合研究大学院大学, 先導科学研究科, 外国人特別研究員
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| 研究期間 (年度) |
2018-11-09 – 2021-03-31
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| キーワード | Intracellular recording / Insect / Vision / Lamina / Spectral sensitivity / Spectral opponency / Papilio xuthus / Modelling |
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| 研究実績の概要 |
We have successfully made a new 21 channel LedSynth device, and used it to measure physiological properties of photoreceptors (PR) and lamina monopolar cells (LMC) in the Papilio xuthus butterfly brain. The new and improved device allows for better spectral control of the stimulating light and thus increases the details for distinguishing between different cell types (PR and LMC). Using this better dataset, we were able to further our mathematical model for lateral inhibition in the lamina, producing a better prediction of response amplitude (positive and negative, relative to the baseline resting membrane potential) based on the spectral composition of the stimulating light and the estimated synaptic connections between cells. On the foundation of this model we calculated the distribution of possible spectral sensitivities of cells depending on the composition of neighboring ommatidial types. Our modeled results show, that the effect of lateral inhibition is mostly due to intraommatidial inhibition. The model is a simplified representation of the real-life situation and of course the modeled predictions will have to be tested experimentally before any conclusions can be made.
Unfortunately, the merger of a LedSynth with a DLP projector proved to be unsuccessful for the lack of light intensity when projecting on to a screen. We thus continued the experiments by positioning the light source in discrete angular steps around the on-axis position and mapped receptive fields of PRs and LMCs. This data needs to be further analyzed.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
We successfully tested the potential merger of a LedSynth with a DLP device and concluded that the output intensity is unfortunately not sufficient for the type of experiments we were interested in. Based on that, we continued measuring the receptive fields with a goniometrically movable point source, which produced useful data for lateral inhibition modeling. The obtained data has been used to further the mathematical model for predicting lateral inhibition effect. We have also modeled the theoretical effect of different neighboring ommatidial types and evaluated the effects of intra- and interommatidial inhibition. Additionally, we made a 21 channel LedSynth device that allows us to measure the physiological properties in a fast and spectrally rich manner. We were able to continue our research project towards obtaining combined physiological and anatomical data for photoreceptors (PRs) and lamina monopolar cells (LMCs) with injecting neurobiotin and its successful visualization under a microscope. The method has proven to be difficult, but nevertheless we were able to establish a protocol which produces results. The next step is to change the labeling to visualize the dendritic arborization of cells and the layered structure of the medulla simultaneously.
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| 今後の研究の推進方策 |
The next step in figuring out the effect of lateral inhibition and neural processing that is taking place in the lamina is to see how the physiologically measured properties coincide with the anatomical structures, how a specific signal is being transmitted further down the visual system. We have started experiments with injecting neurobiotin for cell labeling. The end goal is to produce double staining showing the dendrite arborization of PRs and LMCs in the layers of the medulla, which can be seen by staining cell nuclei. We plan on using a confocal microscope with antibody-bound fluorescent dye. We will mainly focus on the dye injection experiments to produce a solid foundation for connecting physiologically measured characteristics of PRs and LMCs and their connectivity profiles in the lamina and medulla. In the meantime, we will analyze data and prepare results for publications and start writing up the manuscripts for publication of our findings in peer-reviewed journals and on conferences.
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