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Journal ArticleDOI

An autoradiographic examination of the central distribution of the trigeminal, facial, glossopharyngeal, and vagal nerves in the monkey.

01 Apr 1979-The Journal of Comparative Neurology (J Comp Neurol)-Vol. 184, Iss: 3, pp 455-472
TL;DR: The central distributions of primary afferent axons in cranial nerves V, VII, IX, and X have been re‐examined autoradiographically after 3H‐proline injections into their peripheral ganglia to suggest that trigeminal fibers of the ophthalmic and mandibular branches enter the ventrolateral part of the nucleus of the solitary tract (NST).
Abstract: The central distributions of primary afferent axons in cranial nerves V, VII, IX, and X have been re-examined autoradiographically after 3H-proline injections into their peripheral ganglia. Fiber-labeling after subtotal injections of the trigeminal ganglion, besides confirming earlier classical descriptions, suggests that trigeminal fibers of the ophthalmic and mandibular (but not maxillary) branches enter the ventrolateral part of the nucleus of the solitary tract (NST). Injection of VII's geniculate ganglion labels fibers which both ascend and descend upon reaching NST. The ascending fibers distribute in a compact and circumscribed zone immediately dorsal to the spinal V nucleus as far rostral as the caudal pole of the principal trigeminal nucleus. The descending fibers distribute to the lateral NST rostral to the level at which X joins the solitary tract. For a short distance caudal to this level, sparse label is confined to a small part of lateral NST ventral to the solitary tract, which corresponds to the zone receiving direct trigeminal afferents. Fiber-labeling after injections of the ganglia of nerves IX and X suggest the following. Although, upon reaching NST, a few fibers of either IX or X ascend as far rostrally as had those of VII, both have a much larger descending component which distributes to more caudal levels of NST. Most of IX's axons appear to end in the lateral NST; only a few travel as far as the obex. Fibers of X, on the other hand, are abundant in the medial and commissural parts of NST. Moreover, only X appears to have a crossed projection in the commissural nucleus and caudal portion of the contralateral NST. A few fibers of vagal origin also appear to enter the area postrema. Whereas fibers of X appear to constitute the solitary tract, few if any fibers of VII or IX travel within that fascicle. A significant descending components of labeled fibers appears in the spinal V tract when the superior ganglion of either IX or X is injected. These fibers distribute mainly in the pars caudalis of the spinal V nucleus and, to a lesser degree, the cuneate nucleus.
Citations
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Journal ArticleDOI
TL;DR: The autoradiographic material, and additional double-labeling experiments, were used to identify and to characterize projections that interconnect the A1, A2 and A6 regions, as well as possible projections from these cell groups to the spinal cord.

1,099 citations

Journal ArticleDOI
TL;DR: Feelings constitute a crucial component of the mechanisms of life regulation, from simple to complex, and can be found at all levels of the nervous system, from individual neurons to subcortical nuclei and cortical regions.
Abstract: Feelings are mental experiences of body states. They signify physiological need (for example, hunger), tissue injury (for example, pain), optimal function (for example, well-being), threats to the organism (for example, fear or anger) or specific social interactions (for example, compassion, gratitude or love). Feelings constitute a crucial component of the mechanisms of life regulation, from simple to complex. Their neural substrates can be found at all levels of the nervous system, from individual neurons to subcortical nuclei and cortical regions.

852 citations

Journal ArticleDOI
TL;DR: HRP‐labeled perikarya, in contrast to transganglionically transported HRP in sensory terminals in the nTS, were visualized on one side only, thus indicating that motor control via the vagus nerve is exerted only by motor neurons located ipsilaterally.
Abstract: The sensory and motor connections of the cervical vagus nerves and of its inferior ganglion (nodose ganglion) have been traced in the medulla and upper cervical spinal cord of 16 male Wistar rats by using horseradish peroxidase (HRP) neurohistochemistry. The use of tetramethyl benzidine (TMB) as the substrate for HRP permitted the visualization of transganglionic and retrograde transport in sensory nerve terminals and perikarya, respectively. The vagus nerve in the rat enters the medulla in numerous fascicles with points of entry covering the entire lateral aspect of the medulla extending from level +4 to - 6 mm rostrocaudal to the obex. Fascicles of vagal sensory fibers enter the dorsolateral aspect of the medulla and travel to the tractus solitarius (TS) which was labeled for over 8.8 mm in the medulla. The caudal extent of the TS receiving vagal projections was found in lamina V of the cervical spinal cord (C1 to C2). Sensory terminal fields could be visualized bilaterally in the nucleus of the tractus solitarius (nTS), area postrema (ap) and dorsal motor nucleus of the vagus nerve (dmnX). The ipsilateral projection to the nTS and the dmnX was heavier than that found on the contralateral side. The area postrema was intensely labeled on both sides. Motor fibers from HRP-labeled perikarya in the dmnX travel ventromedially in a distinct fascicle and subsequently subdivide into a number of small fiber bundles that traverse the medullary reticular formation in the form of a fine network of HRP-labeled fibers. As these fibers from the dmnX approach the ventrolateral aspect of the medulla they are joined by axons from the nucleus ambiguus (nA), nucleus retroambigualis (nRA) and the retro facial nucleus (nRF). These latter fibers form hairpin loops in the middle of the reticular formation to accompany the axons from the dmnX exiting from the medulla in a ventrolateral location. HRP-labeled perikarya, in contrast to transganglionically transported HRP in sensory terminals in the nTS, were visualized on one side only, thus indicating that motor control via the vagus nerve is exerted only by motor neurons located ipsilaterally. Sensory information on the other hand, diverges to many nuclear subgroups located on both sides of the medulla.

741 citations

Journal ArticleDOI
TL;DR: The prefrontal cortical areas projecting to the NTS apparently overlap to a large degree with those cortical areas receiving mediodorsal thalamic and dopaminergic input, and the retrogradely labeled cortical cells were situated in deep layers of the rat prefrontal cortex.
Abstract: Direct projections from the forebrain to the nucleus of the solitary tract (NTS) and dorsal motor nucleus of the vagus in the rat medulla were mapped in detail using both retrograde axonal transport of the fluorescent tracer True Blue and anterograde axonal transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). In the retrograde tracing studies, cell groups in the medial prefrontal cortex, lateral prefrontal cortex (primarily ventral and posterior agranular insular cortex), bed nucleus of the stria terminalis, central nucleus of the amygdala, paraventricular, arcuate, and posterolateral areas of the hypothalamus were shown to project to the NTS and in some cases also to the dorsal motor nucleus of the vagus. The prefrontal cortical areas projecting to the NTS apparently overlap to a large degree with those cortical areas receiving mediodorsal thalamic and dopaminergic input. The retrogradely labeled cortical cells were situated in deep layers of the rat prefrontal cortex. The anterograde tracing studies revealed a prominent topography in the mediolateral termination pattern of forebrain projections to the rostral part of the NTS and to the dorsal pons. The projections to the NTS were generally bilateral, except for projections from the central nucleus of the amygdala and bed nucleus of the stria terminalis which were predominantly ipsilateral. The prefrontal cortical projections to the NTS travel through the cerebral peduncle and pyramidal tract and terminate throughout the rostrocaudal extent of the NTS. Specifically, the prefrontal cortex innervates dorsal portions of the NTS (lateral part of the dorsal division of the medial solitary nucleus, dorsal part of the lateral solitary nucleus and the caudal midline region of the commissural nucleus), areas which receive relatively sparse subcortical projections. These dorsal portions of the NTS receive major primary afferent projections from the vagal and glossopharyngeal nerves. In contrast, the subcortical projections, which travel through the midbrain and pontine tegmentum, terminate most heavily in the ventral portions of the NTS, i.e., the area immediately dorsal and lateral to the dorsal motor nucleus of the vagus. Only the paraventricular hypothalamic nucleus has substantial terminals throughout the dorsal motor nucleus of the vagus. Hypothalamic cell groups innervate the area postrema and, along with the prefrontal cortex, innervate the zone subjacent to the area postrema.(ABSTRACT TRUNCATED AT 400 WORDS)

735 citations

Journal ArticleDOI
TL;DR: The aim of this study was to map the viscerotopic representation of the upper alimentary tract in the sensory ganglia of the IXth and Xth cranial nerves and in the subnuclei of the solitary and spinal trigeminal tracts.
Abstract: The aim of this study was to map the viscerotopic representation of the upper alimentary tract in the sensory ganglia of the IXth and Xth cranial nerves and in the subnuclei of the solitary and spinal trigeminal tracts. Therefore, in 172 rats 0.5-65 microliters of horseradish peroxidase (HRP), wheat germ agglutinin-HRP, or cholera toxin-HRP were injected into the trunks and major branches of the IXth and Xth cranial nerves as well as into the musculature and mucosa of different levels of the upper alimentary and respiratory tracts. The results demonstrate that the sensory ganglia of the IXth and Xth nerves form a fused ganglionic mass with continuous bridges of cells connecting the proximal and distal portions of the ganglionic complex. Ganglionic perikarya were labeled in crude, overlapping topographical patterns after injections of tracers into nerves and different parts of the upper alimentary tract. After injections into the soft palate, pharynx, esophagus, and stomach, anterograde labeling was differentially distributed in distinct subnuclei in the nucleus of the tractus solitarius (NTS). Palatal and pharyngeal injections resulted primarily in labeling of the interstitial and intermediate subnuclei of the NTS and in the paratrigeminal islands (PTI) and spinal trigeminal complex. Esophageal and stomach wall injections resulted in labeling primarily of the subnucleus centralis and subnucleus gelatinosus, respectively. The distribution of upper alimentary tract vagal-glossopharyngeal afferents in the medulla oblongata has two primary groups of components, i.e., a viscerotopic distribution in the NTS involved in ingestive and respiratory reflexes and a distribution coextensive with fluoride-resistant acid-phosphatase-positive regions of the PTI and spinal trigeminal nucleus presumably involved in visceral reflexes mediated by nociceptive or chemosensitive C fibers.

709 citations

References
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Journal ArticleDOI
TL;DR: There are several reasons for thinking that this method may offer a number of advantages over other currently available techniques, and it should be possible to do this by locally injecting radioactively labeled precursors of proteins or other macromolecules into the brain or spinal cord.

1,523 citations

Journal ArticleDOI
TL;DR: The distribution of best frequencies of neurons and neuron clusters was mapped on the superior temporal plane of the macaque monkey, finding neurons with very similar best frequencies are arrayed both vertically and horizontally.

752 citations