1997 Fiscal Year Final Research Report Summary
Difference of relay modes in synaptic organization of the somatic and visceral thalamic nuclei.
| Project/Area Number |
08680810
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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 |
Nerve anatomy/Neuropathology
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
NAKAMURA Yasuhisa Tokyo Medical & Dental Univ.Faculty of Medicine, Professor, 医学部, 教授 (70025625)
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| Co-Investigator(Kenkyū-buntansha) |
IZUMI Masahide Tokyo Medical & Dental Univ.Faculty of Medicine, Research Associate, 医学部, 助手 (70262186)
SATO Fumi Tokyo Medical & Dental Univ.Faculty of Medicine, Research Associate, 医学部, 助手 (60205961)
OTAKE Kazuyoshi Tokyo Medical & Dental Univ.Faculty of Medicine, Lecturer, 医学部, 講師 (10168966)
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| Project Period (FY) |
1996 – 1997
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| Keywords | thalamus / VL / VA / PVT / MGN / thalamic reticular nucleus / axonal transport / EM 3-D reconstruction |
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| Research Abstract |
We observed light and electron microscopically somatic and visceral thalamic nuclei to know their characteristics of the synaptic organization. Wechose the ventral lateral (VL) and ventral anterior (VA) nuclei as the motor, the medial geniculate nucleus (MGN) as the sensory and the paraventricular thalamic nucleus (PVT) as the visceral nuclei.
In the VL,three-dimensional reconstruction from serial ultrathin sections revealed that cerebellar terminals (CLRs) predominantly made synaptic contacts on primary and secondary dendrites of thalamocortical projection neurons (TCNs), whereas, cortical terminals made synapses on distal dendrites. Presynaptic dendrites (PSDs) of intrinsic neurons and axon terminals of unidentified origins (Ps) made synapses on every order of dendrites and neuronal somata. The synaptic complex (synaptic triad), formed by the CLR,dendrites of the TCN and the PSD was also analyzed. Terminals from the thalamic reticular nucleus (TRN), which belong to P were located independently from the synaptic triad. In the VA,entopeduncular terminals (ELPs) mainly made synaptic contacts with somata and primary dendrites of TCNs. The synaptic triad among the ELP,TCN dendrites and PSD was also observed. Because the ELP is inhibitory in nature, the PSD may play a role of disinhibition against the TCN.TRN terminals in the VA often showed serial synapses in which they were posynaptic to ELPs or terminals with round vesicles.
We studied the corticocortical connections to know the morphological bases of auditory information processing. During this study we examined the relationship between auditory related cortical areas and the subnuclei of the MGN precisely.
About the PVT,we proved that neurons in the Barrington's nucleus which is known as the micturition center sent axons to both the spinal cord and the PVT by axon collaterals. We also observed that many PVT neurons gave off axons to both the limbic cortex and nucleus accumbens by collaterals.
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