| Project/Area Number |
15500147
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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 |
Sensitivity informatics/Soft computing
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| Research Institution | Kochi University of Technology |
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Principal Investigator |
SHINOMORI Keizo Kochi University of Technology, Faculty of Engineering, Department of Information Systems Engineering, Professor, 工学部, 教授 (60299378)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Vision Psychophysics / Color Vision / Aging Effect / Elderly people / Vision / Individual variation / Temporal response / Visual response / 視覚心理物理学 / 視覚情報処理 |
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| Research Abstract |
From the viewpoint of deterioration of ability for visual system by aging, I took up the deterioration of visual information processing speed when elderly people watch stimuli presented in short duration like the case of watching moving images and objects. In this research, I focused on a perception part and investigated an individual variation quantitatively in terms of how the processing speed is affected by aging.
In experiments, I measured individual variation and aging effects in luminous and chromatic impulse response functions (IRFs) by a double-pulse method. In measurement of the chromatic IRFs, I aimed at the S-cone that is the photoreceptor having sensitivity in short wavelength region closest to ultraviolet light. For the S-cone stimulation, I measured individual S-cone confusion line. I analyzed threshold data when two pulses were presented with different intervals and derived luminous and chromatic IRFs for each observer.
As the results, on 70 (in the luminous experiment) and 49 observers (in the chromatic experiment) in 16.6 - 86.3 years old, I succeeded in derivation of luminous and chromatic IRFs. I found that the intensity of visual response was reduced in 49.5% in the luminous response and 44.2% in chromatic responses by aging in this age range. On the other hand, the decline of response speed was not basically observed. Only in the case of luminous IRFs, however, the response functions became slower and did not have an inhibitory phase in 60% of observers older than 60 years old. It suggests that the compensation mechanism of aging effect, in which the age-related decline of signal strength is compensated by increase of summation time, works only in pathways for luminous information but not in ones for chromatic information. It can reflect that luminous information is important in detections of object and motion but information of color is not very much needed for them.
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