1991 Fiscal Year Final Research Report Summary
Information processing mechanisms in the optic tectum.
| Project/Area Number |
01440019
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
神経解剖学
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| Research Institution | Nippon Medical School |
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Principal Investigator |
ITO Hironobu Nippon Medical School, Dept. of Anatomy, Professor, 医学部, 教授 (30046065)
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| Co-Investigator(Kenkyū-buntansha) |
KISHIDA Reiji Yamaguchi University, Sch. of Med., Dept. of Anat., Prof., 医学部, 教授 (50046132)
YOSHIMOTO Masami Nippon Medical School, Dept. of Anatomy, Assistant, 医学部, 助手 (00182832)
UENO Noriyuki Nippon Medical School, Dept. of Anatomy, Assistant, 医学部, 助手 (20184955)
TANUMA Kumiko Nippon Medical School, Dept. of Anatomy, Associate Prof., 医学部, 助教授 (90090977)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Optic Tectum / Visual / Somatosensory / Trigeminal nerve / Correlation center / Information processing / Teleost / Reptile |
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| Research Abstract |
1) Teleost Optic Tectum
In order to clarify correlation mechanisms for two different sensory modalities in the teleost optic tectum, synaptic distribution upon neurons of the nucleus corticalis was studied. The large cells of the@nucleus corticalis are located along the ventromedial edge of the rostral tectum having extremely long dendrites into, two tectal layers, stratum fibrosum et griseum superficiale and stratum griseum centrale. The cortical neurons were retrogradely labeled by injecting HRP into the corpus glomerulosum, and the tissue was treated for electron microscopy.
At least four types of terminals, S2, F2, S4, and S5 were found on the labeled dendrites. S2 terminals showed degenerative changes after contralateral eye enucleation. S4 and S5 terminals were labeled by injecting biocytin into the trigeminal sensory nucleus in the meduffa oblongata. It is highly possible that one particular cortical neuron receives both visual and somatosensory information at the same time.
2) Reptile Optic Tectum
Following HRP injections into the nucleus of lateral descending trigeminal tract, which is a primary sensory nucleus of the trigeminal nerve in ball pythons, labeled fibers and terminals appeared in layers 5-13 of the contralateral optic tectum. Labeled terminals were densely distributed in layers 6-8. After HRP injections into the optic nerve, fibers and terminals in layers 7b-13 were labeled in the contralateral optic tectum. Labeled fibers and terminals were densely packed in layers 12-13. In order to identify neurons which can receive both somatosensory and visual information, the optic tectum was stained with the Golgi method, and tectal neurons were classified on the basis of dendritic arborization. Some neurons have an apical dendrite which arborizes in two levels, layers 6-8 and layers 12-13. Possibility of correlation of visual and somatosensory modalities on such neurons was discussed.
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