Dorsal Root Projections in Various Types of Reptiles

Kusuma, A.; Donkelaar, Hans J. ten

doi:10.1159/000121805

Cited by 31 publications

(5 citation statements)

References 12 publications

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“…In Thamnophis sirtalis, Jacobs and Sis (1980) found a dorsal column projection to the DCN and to the descending vestibular nuclei. Comparable data were obtained in Iguana iguana (Joseph and Whitlock, 1968b) and in Python reticulatus (Kusuma and ten Donkelaar, 1980). In birds, Karten (1963) and van den Akker (1970) noted a spinal projection to the dorsal column nuclei of pigeons, Columba livia.…”

Section: A Comparison Of Spinal Ascending Pathways In Vertebratesmentioning

confidence: 88%

Spinal ascending pathways in amphibians: Cells of origin and main targets

Muñoz

González

et al. 1997

J. Comp. Neurol.

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As part of a research program on the evolution of somatosensory systems in vertebrates, the various components of ascending spinal projections were studied with in vivo and in vitro tract-tracing techniques in representative species of amphibians (the large green frog, Rana perezi, the clawed toad, Xenopus laevis and the ribbed newt, Pleurodeles waltl). Three main ascending sensory channels, each with largely separate targets, were demonstrated: 1. Ascending projections via the dorsal funiculus include primary and nonprimary projections that ascend to terminate mainly in the dorsal column nucleus at obex levels. A small component ascends farther rostralwards to terminate in the reticular formation, the octavolateral area, the trigeminal nuclear complex, and in the granular layer of the cerebellum. 2. Projections ascending via the dorsolateral funiculus reach other spinal and supraspinal targets than the dorsal funicular fibers, mainly ipsilaterally. At upper cervical cord and obex levels, many fibers innervate a region considered the amphibian homologue of the lateral cervical nucleus of mammals. In the medulla, these fibers ascend ventral to the descending trigeminal tract to terminate in the dorsal column and the solitary tract nuclei, and more rostrally, in the reticular formation, the descending trigeminal nucleus and the medial aspect of the ventral octaval nucleus. Major projections reach the area between the facial motor nucleus and the ventral octaval nucleus, and a mediolateral subcerebellar band. These projections arise in neurons located mainly in the ipsilateral deep dorsal and lateral fields throughout the spinal cord. 3. Ascending spinal projections via the ventral quadrant of the spinal cord (the ventral and ventrolateral funiculi) ascend throughout the brainstem up to the diencephalon. Along its course, this component innervates various parts of the reticular formation, the octavolateral area, the granular layer of the cerebellum, the region ventromedial and ventrolateral to the isthmic nucleus, and the subcerebellar region. In the mesencephalon, the torus semicircularis, the midbrain tegmentum and, sparsely, the tectum mesencephali are innervated. Beyond the midbrain, various dorsal and particularly ventral thalamic nuclei and the posterior tubercle are innervated by this ascending sensory channel. The cells of origin of some of these projections were observed in the dorsal, and to a lesser extent, in the lateral and ventral spinal fields of the spinal cord. Evidence for the presence of these three main ascending sensory channels throughout vertebrates will be discussed. The presence of such channels appears to be a shared character in the brain of both amniotes and anamniotes.

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Section: A Comparison Of Spinal Ascending Pathways In Vertebratesmentioning

confidence: 88%

Spinal ascending pathways in amphibians: Cells of origin and main targets

Muñoz

González

et al. 1997

J. Comp. Neurol.

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“…Cutaneous afferents from the rostral scratch receptive field enter the spinal cord via the D3-D6 segmental nerves (Mortin and Stein, 1990). Axons of turtle primary afferents have a central branch that may descend in the ipsilateral spinal cord posterior to the segment of origin; there are no known central branches of turtle primary afferents that descend in the contralateral spinal cord (Kusuma and ten Donkelaar, 1980;Kunzle and Woodson, 1983;Ruigrok et al, 1985). In the present experiments, sites innervated by cutaneous afferents that enter the spinal cord via the D3-D5 segmental nerves were stimulated in the ipsilateral rostral scratch receptive field.…”

Section: Contralateral Pathways Contribute To the Production Of Normamentioning

confidence: 99%

Reconstruction of Flexor/Extensor Alternation during Fictive Rostral Scratching by Two-Site Stimulation in the Spinal Turtle with a Transverse Spinal Hemisection

1998

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Analyses of fictive scratching motor patterns in the spinal turtle with transverse hemisection provided support for the concept of bilateral shared spinal cord circuitry among neurons responsible for generating left- and right-side rostral, pocket, and caudal fictive scratching. Rhythmic bursts of hip flexor activity, the hip extensor deletion variation of fictive rostral scratching, were elicited by ipsilateral stimulation in the rostral scratch receptive field of a spinal turtle [transection at the segmental border between the second (D2) and third (D3) postcervical spinal segments] with a contralateral transverse hemisection one segment anterior to the hindlimb enlargement (at the D6-D7 segmental border). In addition, other sites were stimulated in this preparation: (1) contralateral sites in a rostral, pocket, or caudal scratch receptive field or (2) ipsilateral sites in a caudal scratch receptive field. A reconstructed fictive rostral scratch motor pattern of rhythmic alternation between hip flexor and hip extensor activation was produced by simultaneous stimulation of one site in the ipsilateral rostral scratch receptive field and another site in one of the other scratch receptive fields. This reconstructed rostral scratch motor pattern resembled the normal rostral scratch motor pattern produced by one-site rostral scratch stimulation of a spinal turtle (D2-D3 transection) with no additional transections. The observation of a reconstructed rostral scratch motor pattern produced by two-site stimulation in the spinal turtle with transverse hemisection supports the concept that hip extensor circuitry activated by stimulation of other scratch receptive fields is shared with circuitry activated by ipsilateral rostral scratch receptive field stimulation.

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“…The appearance of these nuclei in reptiles might be associated with the development of limbs which is necessary for the terrestrial life. These nuclei have been found in limbed lizards [14,15,16,17], iguana [18], turtle [19] and alligator American Journal of Medical and Biological Research, 2013, Vol. 1, No.…”

Section: Reptilesmentioning

confidence: 99%

“…The DCN in some tailed-reptiles was divided into large lateral part, considered as the main DCN, and small medial part, referred as the Bi in either side of the midline (e.g., Tegu lizard [15], garter snake [22] and Python [19,23,24]) ( Figure. 2). However, Bi is not described in other tailed-reptiles such as some types of lizards [16], turtles [19] and boas [11].…”

Section: Reptilesmentioning

confidence: 99%

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Functional and Anatomical Features of the Dorsal Column Nuclei in Mammals and Lower Animals

Zaqout

Al-Hussain²

2013

AJMBR

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The dorsal fasciculi of the spinal cord are known as the chief pathways for the conduction of impulses underlying deep sensibility and tactile discrimination from limbs which reach the thalamus and ultimately the cerebral cortex after a relay at a bulbar level, the dorsal column nuclei. It is believed that the development of the dorsal fasciculi and their nuclei in the mammalian and primate series is correlated with increasing sensory discrimination in the skin and the increased development of proprioceptive sense in the limb musculature. In this review we will discuss the reflection of the development of limbs and sensory discrimination in lower animals and mammals on the organization and some functional aspects of these nuclei.

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Dorsal Root Projections in Various Types of Reptiles

Cited by 31 publications

References 12 publications

Spinal ascending pathways in amphibians: Cells of origin and main targets

Spinal ascending pathways in amphibians: Cells of origin and main targets

Reconstruction of Flexor/Extensor Alternation during Fictive Rostral Scratching by Two-Site Stimulation in the Spinal Turtle with a Transverse Spinal Hemisection

Functional and Anatomical Features of the Dorsal Column Nuclei in Mammals and Lower Animals

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