Quantitative studies on motoneurons. II. Spatial and dimensional organization of hypoglossal motoneurons in the boa constrictor, <i>Constrictor constrictor</i>

Ulinski, Philip S.

doi:10.1002/cne.901560407

Cited by 7 publications

(1 citation statement)

References 33 publications

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“…It is still unresolved which fibers, pathways, and nuclei in the brain stem are specifically related to the efferent and afferent fibers and whether the information obtained from mammals is comparable to that in reptiles. Nevertheless, some information has been obtained regarding the central representation of the cranial nerves (IXth, Xth, XIth, XIIth) including sensory nuclei (18,43,131,167), motor nuclei (70,350,629), and both sensory and motor nuclei (37,38,390).…”

Section: G Reptilesmentioning

confidence: 99%

Central Control of the Cardiovascular and Respiratory Systems and Their Interactions in Vertebrates

Taylor

Jordan

Coote

1999

Physiological Reviews

336

278

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This review explores the fundamental neuranatomical and functional bases for integration of the respiratory and cardiovascular systems in vertebrates and traces their evolution through the vertebrate groups, from primarily water-breathing fish and larval amphibians to facultative air-breathers such as lungfish and some adult amphibians and finally obligate air-breathers among the reptiles, birds, and mammals. A comparative account of respiratory rhythm generation leads to consideration of the changing roles in cardiorespiratory integration for central and peripheral chemoreceptors and mechanoreceptors and their central projections. We review evidence of a developing role in the control of cardiorespiratory interactions for the partial relocation from the dorsal motor nucleus of the vagus into the nucleus ambiguus of vagal preganglionic neurons, and in particular those innervating the heart, and for the existence of a functional topography of specific groups of sympathetic preganglionic neurons in the spinal cord. Finally, we consider the mechanisms generating temporal modulation of heart rate, vasomotor tone, and control of the airways in mammals; cardiorespiratory synchrony in fish; and integration of the cardiorespiratory system during intermittent breathing in amphibians, reptiles, and diving birds. Concluding comments suggest areas for further productive research.

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Section: G Reptilesmentioning

confidence: 99%

Central Control of the Cardiovascular and Respiratory Systems and Their Interactions in Vertebrates

Taylor

Jordan

Coote

1999

Physiological Reviews

336

278

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Neural substrates for tongue‐flicking behavior in snakes

Martı́nez-Marcos

Úbeda-Bañón

Halpern

2001

J of Comparative Neurology

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Snakes deliver odorants to the vomeronasal organ by means of tongue-flicks. The rate and pattern of tongue-flick behavior are altered depending on the chemical context. Accordingly, olfactory and vomeronasal information should reach motor centers that control the tongue musculature, namely, the hypoglossal nucleus (XIIN); however, virtually nothing is known about the circuits involved. In the present work, dextran amines were injected into the tongue of garter snakes (Thamnophis sirtalis) to identify the motoneurons of the XIIN. Tracers were then delivered into the XIIN to identify possible afferents of chemical information. Large injections into the XIIN yielded retrograde labeling in two chemosensory areas: the medial amygdala (MA) and the lateral posterior hypothalamic nucleus (LHN). Smaller injections only yielded labeled neurons in the LHN. In fact, the MA, which receives afferents from the accessory olfactory bulb, the rostroventral lateral cortex, and the nucleus sphericus, projects to the LHN. Injections into the MA did not show terminal labeling in the XIIN but in an area lateral to it. However, injections into the LHN gave rise not only to labeled fibers in the XIIN but also to retrograde labeling in the MA, thus confirming the chemosensory input to LHN. Injecting different fluorescent tracers into the tongue and into the LHN corroborated the projection from the LHN to the XIIN. The present report investigates further connections of the olfactory and vomeronasal systems and describes the afferent connections to XIIN in a nonmammalian vertebrate. The circuit for tongue-flicking behavior described herein should be evaluated using functional studies.

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The motor nuclei and primary projections of the IXth, Xth, XIth, and XIIth cranial nerves in the monitor lizard, Varanus exanthematicus

Barbas-Henry

Lohman

1984

J of Comparative Neurology

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The motor nuclei and sensory connections of the IXth, Xth, XIth, and XIIth cranial nerves of the reptile Varanus exanthematicus were studied with the methods of anterograde degeneration and anterograde and retrograde axonal transport. The motor nuclei of nerve IX are located ventrally in the rhombencephalon and are constituted medially by the large-celled glossopharyngeal part of the nucleus ambiguus and laterally by the small-celled nucleus salivatorius inferior. The motor nuclei of nerve X consist of the dorsomedially located dorsal motor nucleus of the vagus and the laterally located vagal part of the nucleus ambiguus. The rostral portion of the latter cell group contains smaller cells than its caudal portion and is rostrally continuous with the nucleus salivatorius inferior of nerve IX. The efferent axons of nerves IX and X arising from the ventrolateral medulla first course dorsomedially, form genua beneath the IVth ventricle, and then exit the brainstem. All primary afferent fibers of nerve IX and the majority of those of nerve X enter the solitary tract. Terminations of vagal fibers were observed in the postvagal portion of the nucleus of the solitary tract, the dorsal motor nucleus of the vagus, and the nucleus of the commissura infima. A small contingent of vagal fibers courses caudally just dorsolateral to the descending trigeminal tract. A separate spinal component of nerve XI could not be found. The bulbar component of this nerve forms part of nerve X and takes its main origin from a detached caudal element of the nucleus ambiguus. The motor nuclear complex of nerve XII consists of a large dorsal nucleus and a small ventral nucleus that extend from the medulla oblongata into the first segment of the cervical spinal cord.

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Quantitative studies on motoneurons. II. Spatial and dimensional organization of hypoglossal motoneurons in the boa constrictor, Constrictor constrictor

Cited by 7 publications

References 33 publications

Central Control of the Cardiovascular and Respiratory Systems and Their Interactions in Vertebrates

Central Control of the Cardiovascular and Respiratory Systems and Their Interactions in Vertebrates

Neural substrates for tongue‐flicking behavior in snakes

The motor nuclei and primary projections of the IXth, Xth, XIth, and XIIth cranial nerves in the monitor lizard, Varanus exanthematicus

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