| Project/Area Number |
05454288
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Pediatrics
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| Research Institution | The Shiga University of Medical Science |
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Principal Investigator |
SHIMADA Morimi The Shiga University of Medical Science, Department of Pediatrics, Professor, 医学部, 教授 (00079873)
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| Co-Investigator(Kenkyū-buntansha) |
AOTANI Hirofumi The Shiga University of Medical Science Pediaterics, Asscistant, 医学部, 助手 (80175744)
ONO Kyokazu The Shiga University of Medical Science Pediatrics, Asscistant, 医学部, 助手 (70252385)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1994: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1993: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | Brain Damage / Neonate / Premature / Neuron / Plasticity / Corticospinal Tract / Axon number / Axon loss / 新生児脳障害 / 未塾児 |
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| Research Abstract |
In this experiment, neuronal plasticity after neonatal corticaldamage was studied with special refernece to the corticospinal tract at the cervical cord of ICR-JCKL mice.
In the suckling mouse before 5 days of age, many growth corns of the corticospinal axons and a few axons containing the electron dense material (EDM) were found in the corticospinal tract (CST) at the cervical cord. The total number of the axons in the CST increased abruptly after the birth to reach its maximum on 14 days of age, and then it decreased rapidly. The total axon number on 56 days was about 32% for its maximum thus losing or being eliminated about 68% of axons once extended.
When the right cerebral cortex was widely damaged by dry-ice on day 0 (operated group), the axons containing EDM in the CST before 5 days of age were significantly less than those of the control. The pattern of the increase and subsequent decrease in total axon number in the operated group were much the same with the control by 21 days of age. However, the decrease in total axon number in the operated group after 21 days was significantly less than that of the control. In the cervical CST of the operated group after 56 days of age, occurrence of small unmyelinated axons was higher than that of age the matched control. These evidences indicate that the neuons in the healthy cerebral cortex show considerable plasticity by active ramification of their parent axons and by the rescue of axons from elimination when rapidly growing cerebral cortex would be damaged.
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