Quantitative electromicroscope study of the oculomotor parasympathetic neurons projecting to the ciliary ganglion in cats: comparison of the synaptic (axo-somatic and axo-proximal dendritic) organization of anterior-dorsal and ventral cell groups

Ichinohe, Noritaka; Shoumura, Kazuhiko; Takahashi, Hitoshi

doi:10.1007/bf00198326

Cited by 3 publications

(3 citation statements)

References 22 publications

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“…In fact, the present experiment revealed that the preganglionic neurons receive as many as seven morphologically distinct types of axon terminals. A previous investigation of cat preganglionic motoneuron ultrastructure had simply divided terminals into those containing spherical and pleomorphic vesicles and allowed identification only of terminals on the cell soma (Ichinohe et al, ). The existence of several types of terminals on labeled preganglionic motoneurons indicates that preganglionic neurons receive input from sources other than from pretectal premotor neurons.…”

Section: Discussionmentioning

confidence: 99%

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Central pupillary light reflex circuits in the cat: II. Morphology, ultrastructure, and inputs of preganglionic motoneurons

Sun

May

2014

J of Comparative Neurology

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Preganglionic motoneurons supplying the ciliary ganglion control lens accommodation and pupil diameter. In cats, these motoneurons make up the preganglionic Edinger-Westphal population, which lies rostral, dorsal and ventral to the oculomotor nucleus. A recent cat study suggested that caudal motoneurons control the lens and rostral motoneurons control the pupil. This led us to examine the morphology, ultrastructure and pretectal inputs of these populations. Preganglionic motoneurons retrogradely labeled by introducing tracer into the cat ciliary ganglion generally fell into two morphologic categories. Fusiform neurons were located rostrally, in the anteromedian nucleus and between the oculomotor nuclei. Multipolar neurons were found caudally, dorsal and ventral to the oculomotor nucleus. The dendrites of preganglionic motoneurons within the anteromedian nucleus crossed the midline, providing a possible basis for consensual responses. Ultrastructurally, several different classes of synaptic profiles contact preganglionic motoneurons, suggesting their activity may be modified by a variety of inputs. Furthermore, there were differences between the synaptic populations contacting the rostral and caudal populations, supporting the contention that these populations display functional differences. Anterogradely labeled pretectal terminals were observed in close association with labeled preganglionic motoneurons, particularly in the rostral population. Ultrastructural analysis revealed that these terminals, packed with clear, spherical vesicles, made asymmetric synaptic contacts onto motoneurons in the rostral population indicating these cells serve the pupillary light reflex. Thus, the preganglionic motoneurons found in the cat display morphologic, ultrastructural and connectional differences suggesting that this rostral preganglionic population is specialized for pupil control, while more caudal elements control the lens.

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Section: Discussionmentioning

confidence: 99%

“…A previous ultrastructural examination of the cat preganglionic motoneurons (Ichinohe et al, ) was also directed at identifying differences between pupil‐ and lens‐related preganglionic motoneurons. However, these authors divided their samples differently, into an anterior–dorsal group and a ventral group.…”

Section: Discussionmentioning

confidence: 99%

Central pupillary light reflex circuits in the cat: II. Morphology, ultrastructure, and inputs of preganglionic motoneurons

Sun

May

2014

J of Comparative Neurology

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“…Despite the critical role of EWpg motoneurons in these two important visual functions, there is relatively little information available about their inputs and ultrastructure in the primate, compared to other mammalian species (Ichinohe et al 1996;Klooster et al 1995;Sun and May 2014a, b). Even the organization of the primate EWpg is a matter of dispute.…”

Section: Introductionmentioning

confidence: 99%

Pupillary light reflex circuits in the macaque monkey: the preganglionic Edinger–Westphal nucleus

et al. 2019

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The motor outflow for the pupillary light reflex originates in the preganglionic motoneuron subdivision of the Edinger-Westphal nucleus (EWpg), which also mediates lens accommodation. Despite their importance for vision, the morphology, ultrastructure and luminance-related inputs of these motoneurons have not been fully described in primates. In macaque monkeys, we labeled EWpg motoneurons from ciliary ganglion and orbital injections. Both approaches indicated preganglionic motoneurons occupy an EWpg organized as a unitary, ipsilateral cell column. When tracers were placed in the pretectal complex, labeled terminals targeted the ipsilateral EWpg and reached contralateral EWpg by crossing both above and below the cerebral aqueduct. They also terminated in the lateral visceral column, a ventrolateral periaqueductal gray region containing neurons projecting to the contralateral pretectum. Combining olivary pretectal and ciliary ganglion injections to determine whether a direct pupillary light reflex projection is present revealed a labeled motoneuron subpopulation that displayed close associations with labeled pretectal terminal boutons. Ultrastructurally, this subpopulation received synaptic contacts from labeled pretectal terminals that contained numerous clear spherical vesicles, suggesting excitation, and scattered dense-core vesicles, suggesting peptidergic co-transmitters. A variety of axon terminal classes, some of which may serve the near response, synapsed on preganglionic motoneurons. Quantitative analysis indicated that pupillary motoneurons receive more inhibitory inputs than lens motoneurons. To summarize, the pupillary light reflex circuit utilizes a monosynaptic, excitatory, bilateral pretectal projection to a distinct subpopulation of EWpg motoneurons. Furthermore, the interconnections between the lateral visceral column and olivary pretectal nucleus may provide pretectal cells with bilateral retinal fields.

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Marked miosis caused by deafferenting the oculomotor nuclear complex in the cat

Ichinohe

Shoumura

2001

Autonomic Neuroscience

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Quantitative electromicroscope study of the oculomotor parasympathetic neurons projecting to the ciliary ganglion in cats: comparison of the synaptic (axo-somatic and axo-proximal dendritic) organization of anterior-dorsal and ventral cell groups

Cited by 3 publications

References 22 publications

Central pupillary light reflex circuits in the cat: II. Morphology, ultrastructure, and inputs of preganglionic motoneurons

Central pupillary light reflex circuits in the cat: II. Morphology, ultrastructure, and inputs of preganglionic motoneurons

Pupillary light reflex circuits in the macaque monkey: the preganglionic Edinger–Westphal nucleus

Marked miosis caused by deafferenting the oculomotor nuclear complex in the cat

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