Afferent connections to the sensory trigeminal nuclei, the nucleus of the solitary tract and adjacent structures. An experimental study in the rat

Torvik, Ansgar

doi:10.1002/cne.901060104

Cited by 751 publications

(184 citation statements)

References 73 publications

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“…Early studies by Allen (1923), using the Marchi method, su! {gested this, and subsequent experiments by both Astrom (1953) and Torvik (1956) supported such a conclusion. The course of secondary gustatory fibers, however, remained uncertain for many years, principally because of the difficulty in producing small lesions within this region and/or verifying that experimental lesions involved secondary gustatory neurons within the SOL.…”

Section: Central Gustatory Pathwaysmentioning

confidence: 74%

The gustatory neocortex of the rat

1982

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Research findings related to the functional significance of the gustatory neocortical system of the rat are reviewed and interpreted. Studies of gustatory neocortex (GN) involvement in taste-related cognitive processes are emphasized after briefly reviewing GN anatomy and physiology. Evidence is presented supporting the conclusion that the GN contributes relatively little to fundamental taste reactivity, but is deeply involved in cognitive (learning and memorial) taste processes; that is, "reactive salience" to taste stimuli is preserved following GN ablation, while "associative salience" is markedly degraded. Apparent functional similarities between GN and other sensory neocortical areas are emphasized throughout the paper, and a hierarchical view of gustatory system functioning is addressed.Patton began his 1950 review of the chemical senses by pointing out that taste and smell essentially had been neglected relative to the other sensory systems. As a partial explanation for this neglect, he men-

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Section: Central Gustatory Pathwaysmentioning

confidence: 74%

The gustatory neocortex of the rat

1982

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“…Under the present experimental conditions, the anaesthetics (urethane plus pentobarbitone) administered to the rat could depress activity evoked by C fibres, whilst the faster, more synchronized responses to Ad fibre activation may be more resistant to anaesthetics. On the basis of anatomical and electrophysiological data obtained in several species, the main pathways responsible for the transmission of the nociceptive information in the spinal cord are the ventrolateral (Torvik, 1956;Zemlan, Leonard, Kow & Pfaff, 1978) and possible dorsolateral pathways (McMahon & Wall, 1983;Hylden, Anton & Nahin, 1989), terminating within the brain stem reticular formation and the thalamus. The RVL-spinal 'vasomotor' neurones could receive a collateral input from the lateral spinothalamic tract and/or a direct input from the spinoreticular tract (Torvik, 1956;Zemlan et al 1978;Kevetter & Willis, 1983), though this remains to be investigated.…”

Section: Discussionmentioning

confidence: 99%

Nociceptive inputs into rostral ventrolateral medulla‐spinal vasomotor neurones in rats.

Sun

Spyer

1991

The Journal of Physiology

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SUMMARY1. In anaesthetized rats recordings were made from thirty-eight neurones in the rostral ventrolateral medulla (RVL) with spinal-projecting axons. Their responses to mechanical, thermal and/or electrical stimulation were examined as were the accompanying changes in arterial pressure.2. Mechanical, thermal and electrical stimulation of either hindpaw at a strength that can be regarded as noxious produced a consistent rise in arterial pressure. RVL-spinal-projecting 'vasomotor' neurones were excited by the noxious mechanical and thermal (52°C) stimulation at a latency that was shorter than that of the evoked pressor response.3. Percutaneous electrical stimulation of either hindlimb extremity resulted in an early peak of excitation (fourteen out of fourteen), an early trough of inhibition (twelve out fourteen), and a later peak of excitation (two out of fourteen). This response pattern to stimulation of either limb was independent of which limb was activated, but contralateral hindpaw stimulation elicited excitation at a shorter latency. The differences in latency of responses to stimulating two locations along the tail suggested that the early excitation and inhibition of RVL-spinal 'vasomotor' neurones were evoked by activation of peripheral fibres with a mean conduction velocity in the Ad range.4. Short-latency excitatory and inhibitory responses in RVL-spinal 'vasomotor' neurones were observed also when single-pulse stimuli were delivered within the lateral part of the spinal cord. 5. lonophoretic application of bicuculline, a GABAA receptor antagonist, blocked the evoked inhibition of these neurones on electrical stimulation of the hindpaw without attenuating the excitatory input from the same stimulus.6. These results indicate that RVL-spinal 'vasomotor' neurones receive an input from cutaneous nociceptive afferents. This suggests that these neurones mediate, at least partly, the cardiovascular responses related to nociceptor stimulation.

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“…Both anatomical and physiological evidence is available to support the idea that the LRF contains cells that are related to the trigeminal system. The LRF is contiguous dorsolaterally with the trigeminal spinal nucleus, and no obvious borders between them exist (Torvik, 1956). In addition, cells within and adjacent to the trigeminal nuclear complex (within the LRF) are activated by noxious and/or non-noxious stimulation of the trigeminal receptive field (Segundo et al, 1967;Nord and Kyler, 1968;Nord and Ross, 1973;Azerad et al, 1982) in a manner dependent upon stimulus intensity (Burton, 1968;Biedenbach, 1977).…”

Section: Pontomedullary Locomotor Stripmentioning

confidence: 99%

Locomotion produced in mesencephalic cats by injections of putative transmitter substances and antagonists into the medial reticular formation and the pontomedullary locomotor strip

1988

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The purpose of this study was to determine the distribution of cells in the medial reticular formation (MRF) and the pontomedullary locomotor strip (PLS), which can induce locomotion when activated. Controlled microinjections of neuroactive substances (Goodchild et al., 1982) into the MRF or PLS were made in order to activate cell bodies in those areas. The ability of trigeminal receptive field stimulation to induce locomotion before and after drug infusion into the PLS was also assessed since the PLS and the spinal nucleus of the trigeminal nerve are similar in their anatomical distribution. Experiments were performed on precollicular-postmamillary decerebrate cats walking on a treadmill. Injections of glutamic acid (GA; 500 nmol) into the MRF produced locomotion that was antagonized by infusion of glutamic acid diethyl ester into the same spot. Decreases in the current threshold for locomotion produced by electrical stimulation of the MRF were observed when the MRF was infused with either GA (40–80 nmol), DL- homocysteic acid (DL-HCA; 200 nmol), or picrotoxin (PIC; 15 nmol). Injections of GA (100 nmol), DL-HCA (700 nmol), PIC (10–50 nmol), and substance P (2 nmol) into the PLS also produced locomotion. Locomotion produced by injections of PIC into the PLS was blocked by infusion of equal amounts of muscimol or GABA. Effective PLS injection sites were all confined to the trigeminal spinal nucleus or immediately ventral and medial to this in the adjacent lateral reticular formation. Trigeminal nerve peripheral field stimulation evoked locomotion after microinjection of PIC into the PLS, although this same facial stimulus was not effective prior to drug injection. We conclude that the MRF and PLS regions of the cat brain stem contain cells that produce locomotion when chemically stimulated, and we suggest that the PLS is closely related to or synonymous with the spinal nucleus of the trigeminal nerve. Furthermore, we suggest that stimulation of trigeminal afferents is analogous to stimulation of segmental afferent pathways in the production of locomotion (Sherrington, 1910; Jankowska et al., 1967; Afelt, 1970; Budakova, 1972; Grillner and Zangger, 1979).

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Afferent connections to the sensory trigeminal nuclei, the nucleus of the solitary tract and adjacent structures. An experimental study in the rat

Cited by 751 publications

References 73 publications

The gustatory neocortex of the rat

The gustatory neocortex of the rat

Nociceptive inputs into rostral ventrolateral medulla‐spinal vasomotor neurones in rats.

Locomotion produced in mesencephalic cats by injections of putative transmitter substances and antagonists into the medial reticular formation and the pontomedullary locomotor strip

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