| Project/Area Number |
17500195
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bioinformatics/Life informatics
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| Research Institution | Aichi Prefectural University |
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Principal Investigator |
KAMIYAMA Yoshimi Aichi Prefectural University, Faculty of Information Science and Technology, Associate Professor (70233963)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,730,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥330,000)
Fiscal Year 2007: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Retina / Neuron Model / Neuroinformatics / Rod Photoreceptor / Retinal Ganglion Cell / Neural Spikes / 数理モデル / シミュレーション / イオンチャネル / ニューロン / 杆体 |
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| Research Abstract |
The vertebrate retina has been thought to be a window to the brain because of its accessibility and suitability for neuroscientific investigation. It is thought to be one of the few parts of the vertebrate brain where we can reasonably explain its purpose and how it works. The retina is an ideal model of an information processing neural network, describing how neurons interact to codify and process visual information. Over the last decade, we have developed mathematical models of retinal neurons based on biophysical details. These models can reveal what happens if a particular ionic current is active or inactive. One can then ask what advantages are given on the visual system by having the particular class of ion channel present in the neuron.
In this study, we analyzed the underlying mechanisms of a rod photoreceptor that behaves as a bandpass filter. The simulated frequency response revealed that a single rod behaves as a bandpass filter whose characteristics are affected by the stimulus strength and frequency. We analyzed the contribution of individual ionic currents to bandpass filtering and found that the filtering of small signals is largely regulated by the calcium-dependent currents, whereas the filtering of large signals is regulated by the hyperpolarization-activated current. The major discovery was that the kinetics of the ionic currents, IK(Ca), ICl(Ca), and Ih characterize the bandpass filtering of rod signals. We also developed a stochastic model of spike generation in retinal ganglion cells. The stochastic model succeeded to reproduce precise and reliable spikes to flucutuating current injection. We found the spike timing variability was much influenced by the outward K currents, IKv and IA.
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