2001 Fiscal Year Final Research Report Summary
Integration of the otolish and semicircular canals on single vestibular neurons
| Project/Area Number |
12671682
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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 |
Otorhinolaryngology
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| Research Institution | Tokyo Medical University |
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Principal Investigator |
UCHINO Yoshio Tokyo Medical University, Medicine, Professor, 医学部, 教授 (00086555)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Hitoshi Tokyo Medical University Medicinem Assistant professor, 医学部, 講師 (80154087)
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| Project Period (FY) |
2000 – 2001
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| Keywords | vestibular nerve / semicircular canal / otolith / dizziness / icuiburium system / utricular nerve / saccular / linear accereation |
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| Research Abstract |
(1)Commissural effects in the otolith system. Exp Brain es. 136, 421-430, (2001). We examined whether otolith-catibated vestibular neurons received commissural inhibition from the contralateral otolithic macula orented in the same geometric plane. More than half of the utricular (UT)-activated vestibular neurons received mommissural inhibition from the contralateral UT nerve. Approximately 10% of saccular (SAC)-activated vcstibular neurons received commissural inhibition. The present findings suggest that many UT-activated vestibular neurons receive commissursal inhibition, which may provide a mcchanism for increasing the sensitivity of vestibular neurons to horizontal linear acceleration and lateral tilt of the head. Commissural inhibition in the SAC system was less prominent than in the UT system. (2) Convergence of the horizontal semicircular canal and otolith afferents on cat single vestibular neurons. Exp Brain es.140, 1-11(2001). We studied the convergence of two afferent pairs t
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o single vestibular neurons by selective stimulation of the horizontal semicircular canal (HC)and SAC nerves, and the HC and UT nerves in decerebrated cats. Of a total of 125 neurons activated by stimulation of the HC/SAC nerves, 17% received convergent inputs. About half of the convergent neurons were classified as vestibulospinal neurons. In 80 neurons studied by stimulation of the HC/UT nerves, both inputs converged in 15% neurons and more than half of which were vestibulospinal neurons. The percentages of HC/SAC and HC/UT convergence were half those of the posterior semicircular canal (PC), PC/SAC(33%)and PC/UT(33%) convergence, respectively. The convergent neurons receiving the HC and otolith inputs may contribute at least partly to the vestibulocollic reflex. (3) Otolith-activated vestibulothalamic neurons in cats.. Exp Brain es, 141, 415-424(2001). The components of the vestibular ascending pathway that transmit otolith information to the thalamus were studied electrophysiologically in anesthetized cats. Otolith inputs to these neurons were examined with selective stimulation of the UT or the SAC nerves. Most of the neurons (38/40)were antidromically activated by focal stimulation of the ventral part of the ipsilateral thalamus. Only three SAC-activated vestibulo-thalamic nuerons were antidromically activated by stimulation of the contralateral thalamus, in marked contrast to the UT-activated vestibulo-thalamic neurons. Less
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