| Project/Area Number |
61480103
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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 |
Neurophysiology and muscle physiology
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| Research Institution | University of Tokyo |
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Principal Investigator |
HONGO Toshinori University of Tokyo, Professor, 医学部, 教授 (60013843)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1988: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | skin reflex / interneurone / premotor neurone / corticospinal tract / rubrospinal tract / spinal cord / ネコ / 運動ニューロン / 指 / 体部位局在 / 部位特異性 |
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| Research Abstract |
Organizations of skin reflex pathways in the cat forelimb and hindlimb were investigated. The following results were obtained.
1. Spatial patterns of reflexes evoked from central and toe pads. Stimulation of the central pad of the foot evoked extension of all the toes, while that of the toe pad evoked a special pattern of reflexes typical of the toe stimulated. The reflex patterns were essentially the same whether stimulated mechanically (pressure) or electrically, and both in the hand and the foot. It was suggested that these reflexes play an important role in equalizing force distribution over the glabrous skin area.
2. Facilitatory actions of the corticospinal (CST) and rubrospinal tracts (RST). Stimulation of these descending tracts facilitated skin reflexes at an interneuronal level. Central latencies of the facilitated skin reflex effects were 1.1 - 3.0 msec for CST and 1.6 - 3.4 msec for RST. It was suggested that the two tracts acts on separate interneurones of skin reflex pathways partly.
3. Intraspinal route of reflexes from pads to toe extensor motoneurones. Both in the hand and the foot, afferent fibres from pads entered the cord via dorsal roots rostral to the motor nuclei of intrinsic toe extensors. The reflex actions were conveyed caudally by interneuronal axons which projected to the target motor nuclei.
4. Identification of premotor neurones in the skin reflex pathways. Premotor neurones of skin reflex pathways were identified by means of intracellular staining of interneuronal axons with HRP, threshold mapping for antidromic excitation of an interneurone, and interneurone-spike-triggered averaging of motoneuronal membrane potentials. Thus identified premotor neurones lay mainly in Rexed's laminae V-VI and descended in the lateral funiculus to project to motoneurones. Excitatory and inhibitory premotor neurones of both disynaptic and polysynaptic pathways were successfully identified.
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