Trigemino-thalamic fibre connections in the goat. An experimental anatomical study

Karamanlidis, A.N.; Voogd, Jan

doi:10.1159/000143472

Cited by 19 publications

(1 citation statement)

References 3 publications

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“…Experimental studies in Artiodactyla (Capra: Karamanlidis and Voogd 1970) and Perissodactyla (donkey: Karamanlidis, unpublished) showed the presence of an extensive ipsilateral projection arising from the nucleus princeps and the absence of a crossed trigeminothalamic projection from that nucleus (Karamanlidis and Voogd 1970). The dorsal trigeminothalamic tract in the goat and other artiodactyls and perissodactyls is large and located lateral to the periaqueductal grey, where it overlaps with the central reticular fasciculus (see Fig.…”

Section: Trigeminal Sensory Systemmentioning

confidence: 97%

Mammals

Voogd¹,

Nieuwenhuys²,

Dongen³

et al. 1998

The Central Nervous System of Vertebrates

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107

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Section: Trigeminal Sensory Systemmentioning

confidence: 97%

Mammals

Voogd¹,

Nieuwenhuys²,

Dongen³

et al. 1998

The Central Nervous System of Vertebrates

Self Cite

107

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The ascending fiber projections from the principal sensory trigeminal nucleus in the rat

Smith

1973

J of Comparative Neurology

164

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Persisting reports of uncrossed secondary trigeminothalamic pathways originating from the principal sensory trigeminal nucleus (PrV) are based mainly on data obtained from surgically induced lesions analyzed by methods other than reduced silver impregnation techniques. After complete stereotaxic or direct surgical lesions of PrV, degenerating fibers proceed ventrally and rostrally from the nucleus and cross the midline in the rostral pons, completing their decussation caudal to nucleus interpeduncularis. These fibers form a large trigeminal lemniscus that ascends through the midbrain dorsomedial to the smaller medial lemniscus. PrV fibers terminate in the posterior thalamic nucleus and throughout the medial two-thirds of the ventrobasal thalamic complex (VBm) contralateral to the side of the lesion. Connections with the ventral part of zona incerta were also found similar to those reported for the medial lemniscus.Another fiber system proceeds dorsad from the parvicellular reticular formation in the PrV region and terminates on cells of the ipsi-and contralateral motor trigeminal nuclei and the adjacent contralateral parvicellular reticular formation. Differential lesions indicate that these "intertrigeminal" commissural connections arise chiefly from the parvicellular reticular formation that lies between PrV and the motor trigeminal nucleus.These experiments, which also included selective lesions of dorsal and rostral portions of PrV, failed to produce any evidence supporting the existence of an uncrossed principal sensory trigeminothalamic pathway in the rat. While selective, ventral zona incerta PrV connections can be demonstrated, no PrV intralaminar projections appear to exist. Initial findings show that comparable fully decussated PrV-VBm connections also exist in the guinea pig but that some ipsilaterally ascending fibers occur in monkeys (Smith, '72). These and other recent data demonstrate that phyletic neural variations exist in the PrV-thalamic projections in various mammalian species.Although many techniques have been used to investigate secondary trigeminal sensory connections in a variety of animal species, differing and sometimes contradictory results have produced controversies concerning the course and sidedness of principal sensory nuclear projections in various species (Wallenberg, 1896, '05; von Economo, '11; Papez and Rundles, '37; Russell, '54; Carpenter, '57; Torvik, '57; Emmers, '65; '66; Karamanlidis and Voogd, '70; Mizuno, '70 neurophysiological activities have sometimes been inconclusive, and some authors disagree as to the course of secondary trigeminal fiber projections in the same species. In the cat, for example, a dorsal ipsilateral ascending component, in addition to the ventral contralateral lemniscal pathway, has been both reported and later denied (Russell, '54 '71). Viewed collectively these reports suggest that some species differences might exist and that interspeies generalizations should therefore be approached with caution.The aim of this investigation was t...

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Species differences in mechanosensory projections from the mouth to the ventrobasal thalamus

Bombardieri

Johnson

Campos

1975

J of Comparative Neurology

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To determine whether the largely ipsilateral, inverted representation of mouth parts in the ventrobasal thalamus of sheep was unique to that species or an expansion of a general mammalian pattern, the corresponding thalamic projections were mapped electrophysiologically in a selected series of mammals (oppossums, agoutis, squirrel monkeys, cats, raccoons, and sheep) representing major branches of evolution among therian mammals. In mapping, tungsten microelectrodes were used to record multi-unit discharges in the thalamus in response to mechanical stimulation of oral surfaces. The pattern of projections seen in sheep is not a general mammalian pattern; there is extensive variability among mammals in the laterality and internal orgainzation of the projections from the mouth. In spite of the great variability, the results suggest an hypothesis concerning phylogenetic trends: descendants of palaeoryctoid insectivores (cats, raccoons, and sheep in our sample) have extensive ipsilateral projections from the mouth, in other therian mammals (opossums, agoutis, and squirrel monkeys in our sample) the ipsilateral component is small or absent.

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Trigemino-thalamic fibre connections in the goat. An experimental anatomical study

Cited by 19 publications

References 3 publications

Mammals

Mammals

The ascending fiber projections from the principal sensory trigeminal nucleus in the rat

Species differences in mechanosensory projections from the mouth to the ventrobasal thalamus

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