bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of segmental nerves to the developing rat diaphragm: Absence of pioneer axons
Authors: Noakes P. G. , Bennett M. R. , Davey D. F. 
Published: January 2005

AbstractA study has been made of the growth of cervical nerves C3‐C6 to the ral diaphragm. At 11 days of embryonic age these cervical nerves first project out of the spinal cord toward the cardinal veins and later form the left and right phrenic nerve trunks. During the next 2 days, the phrenic nerves grow caudally in close association with the cardinal veins toward the diaphragm. At the growing tips of these nerve trunks the growth cones of axons were observed every 1–2 μm. The last axon did not project more than 2 μm ahead of any neighbouring axons. At 14 days the phrenic nerves reach the level of the developing diaphragm and converge into pools of premuscle cells. Previous studies have suggested that the phrenic nerve enters the premuscle masses of the diaphragm at an early developmental stage when the premuscle masses; are at approximately the segmenlal levels C3‐C6 This study shows that the phrenic nerves must grow to more caudal levels in order to reach the premuscle cells of the diaphragm. Furthermore, the leading axons of the phrenic nerve trunk do not project in a pioneering fashion, far in advance of the trailing axons.
Cytoarchitecture and topographic projections of the gustatory centers in a teleost, Carassius carassius
Authors: Morita Yasuhiro , Murakami Takeshi , Ito Hironobu 
Published: January 2005

AbstractThe neuronal connections in the central gustatory system of the crucian carp were examined by means of degeneration and HRP methods. Cell morphology in the primary gustatory lobes was studied in Golgi‐impregnated material.Medium‐sized neurons of the facial lobe emit axons which project to the secondary gustatory nucleus. The nucleus intermedius facialis of Herrick ('05) projects bilaterally. Large neurons send axons through the spinal trigeminal tract to terminate in the spinal trigeminal nucleus and in the medial funicular nucleus. In the vagal lobs, second‐order neurons for the ascending projections are located in the superficial part of the sensory zone. These neurons project exclusively to the ipsilateral secondary gustatory nucleus. Neurons located in the deeper part of the sensory zone send axons to the motor zone and to the brainstem reticular formation to form short reflex arcs. The glossopharyngeal lobe has similar neuronal connections to the vagal sensory zone.Both facial and vagal lobes receive afferent projections from the following central structures: nucleus posterioris thalami, nucleus diffusus lobi inferioris, optic tectum, motor nucleus of the trigeminal nerve, medullary reticular formation, and the gray matter of the upper spinal cord. The facial lobe has an additional afferent from the mesencephalic reticular formation. The major sources to the medullary gustatory lobes are the nucleus posterioris thalami and nucleus diffusus lobi inferioris.Each type of neuron classified by morphology and location in the facial, glossopharyngeal, and vagal Jobes was correlated with its particular destination. Topographic projections were demonstrated in the secondary and tertiary gustatory centers.
Postnatal development of caudate input neurons in the cat
Authors: Fisher Robin S. , Levine Michael S. , Gazzara Russell A. , Hull Chester D. , Buchwald Nathaniel A. 
Published: January 2005

AbstractLectin‐bound horseradish peroxidase (WG‐HRP) was pressure‐injected into the caudate nucleus (Cd) of neonatal (< 24 hours of age) and adult cats in order to assess the postnatal development of monosynaptic Cd input neurons. Tissue was processed for peroxidase activity with a benzidine dihydrochloride chromagen. The injection of WG‐HRP produced relatively similar labelled zones of marker uptake in the caudate nuclei of both neonates and adults. Similar axonal projections were also labelled in both age groups. While many characteristics of retrogradely labelled Cd input neurons were apparently constant throughout postnatal life, each of these features had a particular developmental modification. (1) Regardless of age, neuronal somata that projected to the Cd were located in the neocortex, thalamus, substantia nigra, mesencephalic raphe nuclei, and globus pallidus. In each of these brain sites, labelled Cd input neurons appeared to migrate postnatally. (2) The Cd afferent axons originated from the same neuronal lines in neonates and adults‐small‐to‐medium‐sized cortical neurons and medium‐sized‐to‐large fusiform cells in all other brain sites. In each of the brain sites, labelled neurons displayed marked postnatal somatic growth. (3) In both age groups, there was a characteristic intrasomatic reaction product density in the labelled neurons located in each brain site (substantia nigra > thalamus = raphe = globus pallidus > cortex). In each of these brain sites, the intrasomatic reaction product density was less in neonates than in adults.
The inferior olive of a prosimian primate Galago senegalensis. I. conformation and spino‐olivary projections
Authors: Whitworth R. H. , Haines D. E. 
Published: January 2005

AbstractSpino‐olivary projections to inferior olive (10)in a prosimian primate, Galago senegalensis, were studied by using a modification of the Fink and Heimer ('67) technique. Prior to examining the arrangement of spinal axons within 10, its conformation was determined from a series of cresyl violet acetate sections. Galago I0 is composed of typical medial accessory (MAO), dorsal accessory (DAO), and principal (PO) olivary nuclei. The MA0 is divisible into subgroups a, b, c, d, a ventrolateral outgrowth (VLO), and a dorsomedial cell column (DMCC). Cytoarchitectural and experimental data indicate that DAO is subdivided into lateral (DAOI) and medial (DAO,) parts. The PO of Galago consists of dorsal and ventral lamellae connected by a lateral bend.Following hemisections of the spinal cord at cervical, thoracic, and lumbar cord levels, degeneration is present in essentially identical subgroups of Galago 10. The preponderance of degeneration is found throughout the ros‐ trocaudal extent of ipsilateral DAO1. Moderate amounts of axonal debris are located in caudal parts of subgroup a of ipsilateral MAO, and only a few degenerated fibers extend into adjacent subgroup b after cervical lesions. A distinct contralateral component is evident only following a C1 hemisection. The moderate numbers of degenerated axons found in contralateral DAOM arise exclusively from cervical levels C1 to C3. Spinoalivary fibers terminating in MAO appear to ascend in the ventral funiculus while the majority of those to DAOlcourse through the lateral funiculus.
Cytoarchitecture and ultrastructure of nucleus prethalamicus, with special reference to degenerating afferents from optic tectum and telencephalon, in a teleost (Holocentrus ascensionis)
Authors: Ito Hironobu , Vanegas Horacio 
Published: January 2005

AbstractHistological structure and neuronal geometry of the nucleus prethalamicus of holocentrid teleosts, which is homologous to the nucleus rotundus of reptiles and birds and to the nucleus lateralis posterior‐pulvinar complex of mammals, were studied by means of the Bodian, Nissl, toluidine blue, and Golgi methods. Synaptic terminals were classified electron microscopically, and terminal types originating from the telencephalon and the optic tectum were determined by electron microscopy in degeneration experiments.The nucleus prethalamicus is composed of four layers, in the following order from medial to lateral: a small‐cell layer, a plexiform layer, a large‐cell layer, and a marginal layer. Six types of terminals (U, L, Sp, Sd, F, and P) were distinguished in the nucleus, and the distribution pattern for each type of terminal was determined by counting its relative number in each layer. Sp terminals make synaptic contacts with small‐cell dendrites or somata in the small‐cell layer, and degenerate after telencephalic ablations. Sd terminals synapse exclusively with spines of large‐cell dendrites in both marginal and large‐cell layers, and degenerate after tectal ablations.Because only large neurons have been labeled after HRP injections into the telencephalon (Ito et al., '80, '82; Ebbesson, '80; Murakami et al., '83), it is considered that these neurons relay visual information from the optic tectum onto the telencephalon. It is hypothesized that the small neurons in the nucleus, which receive telencephalic input, might modulate the large neurons' relay function.
Organization of the efferent projections of the medial superior olivary nucleus in the cat as revealed by HRP and autoradiographic tracing methods
Authors: Henkel Craig K. , Spangler Kevin M. 
Published: January 2005

AbstractFeatures of the organization of the efferent axonal projections from the medial superior olivary nucleus (MSO) in the cat were studied. In order to determine the origin and distribution of projections from MSO, the retrograde horseradish peroxidase (HRP) and autoradiographic tracing methods were used. The results showed that (1) in both HRP and autoradiographic studies the projection to the inferior colliculus was largely ipsilateral, although a contralateral component was present; (2) the projection field of MSO was confined to the ventral division of the central nucleus of the Inferior colliculus, and within this field the labeling was heavier in the rostral and dorsolateral parts of the ventral division; (3) the projection to the inferior colliculus was topographic with ventral parts of MSO projecting ventrally and dorsal parts of MSO projecting dorsolaterally; (4) the projection field in the central nucleus formed successive laminae oriented from ventro‐lateral to dorsomedial; (5) the axonal course was via the medial or internal segment of the lateral lemniscus; and (6) some fibers in this course ended additionally within the dorsal nucleus of the lateral lemniscus. This latter projection was also topographically organized. These observations supported previously described features of lamination and tonotopic order for afferents of the inferior colliculus, as well as recent suggestions that functional segregation of afferent connections exists within the laminated portion of the central nucleus of the inferior colliculus.
Separate origins for the dynorphin and enkephalin immunoreactive fibers in the inferior mesenteric ganglion of the guinea pig
Authors: Dalsgaard C. J. , Vincent S. R. , Hökfblt T. , Christensson I. , Terenius L. 
Published: January 2005

AbstractBy different denervation procedures the origin of dynorphin‐(1–17) and enkephalin immunoreactive fibers in the guinea pig inferior mesenteric ganglion was investigated. It was found that the dynorphin‐(1–17)‐positive fibers reached the ganglion predominantly via the colonic nerves and to a lesser extent via the hypogastric and intermesenteric nerves whereas the enkephalin‐positive fibers reached the ganglion via the lumbar splanchnic nerves. These findings show that the dynorphin‐(1–17) and enkephalin systems are separate in this ganglion.
Projections of the amygdala to the thalamus in the cynomolgus monkey
Authors: Aggleton J. P. , Mishkin M. 
Published: January 2005

AbstractThe projections of the amygdala to the thalamus in cynomolgus monkeys (Macaca fascicularis) were studied with both anterograde and retrograde axonal tracing techniques. Horseradish peroxidase (HRP) was injected into medial and midline thalamic sites in five animals, and tritiated amino acids were injected into selected amygdaloid regions in a total of 13 hemispheres in ten animals. The findings from the two types of tracer experiments demonstrated the origins, course, and terminal pattern of amygdaloid projections to two thalamic nuclei – medialis dorsalis (MD) and reuniens. Almost all of the amygdaloid nuclei contribute projections to MD, though the greatest proportion arise from the basal group and terminate in discrete, interlocking patches within the medial, magnocellular portion of MD. In addition to this major projection, the central and medial amygdaloid nuclei send a lighter projection to the lateral portion of nucleus reuniens. The amygdalothalamic projections took a variety of routes out of the amygdala before the large majority joined the interior thalamic peduncle and entered the rostral head of the thalamus where they turned caudally toward their targets. A small number of amygdalothalamic fibers may also run in the stria terminalis.
Tritiated 2‐deoxy‐D‐glucose: A high‐resolution marker for autoradiographic localization of brain metabolism
Authors: Hammer Ronald P. , Herkenham Miles 
Published: January 2005

AbstractThe technique for autoradiographic localization of 2‐deoxy‐D‐glucose (2DG) uptake has become a useful method for observing alterations of functional brain activity resulting from experimental manipulation. Autoradiographic resolution is improved using tritiated ([3H]) rather than carbon‐14 ([14C])2DG, due to the lower energy and shorter path of tritium emissions. In addition, lower 2DG uptake by white matter relative to gray matter is exaggerated in the [3H]2DG autoradiographs due to the greater absorption of tritium emissions by lipids. Using [3H]2DG, it is possible to observe differential metabolic labeling in various individual nuclei or portions of nuclei that is unresolvable using [14C]2DG in the awake, normal animal. Heterogeneous patterns of 2DG uptake seen only with [3H]2DG are found in the nucleus accumbens, the anterior portion of the basolateral nucleus of the amygdala, specific nuclei of the inferior olivary complex, various hypothalamic regions, and a region straddling the border of the medial and lateral habenular nuclei. The lamination of differential 2DG uptake in the hippocampus is better localized using [3H]2DG. Autoradiographic resolution of labeled 2DG is further improved when the brain is perfused prior to frozen sectioning, due perhaps to selective fixation and retention of intracellular labeled 2‐deoxy‐glycogen. A series of [3H]2DG autoradiographs are presented together with views of the Nissl‐stained sections that produced the autoradiographs.
Effects of monocular deprivation on geniculocortical synapses in the cat
Authors: Tieman Suzannah Bliss 
Published: January 2005

AbstractIn monocularly deprived (MD) cats, many cells in the lateral geniculate nucleus (LGN) but few cells in the visual cortex respond to input from the deprived eye, suggesting that the connections to visual cortex from the deprived geniculate laminae may have been disrupted. I have examined these connections in MD cats by using electron microscopic autoradiography of visual cortex after injections of tritiated lysine into single laminae of LGN. After injections into either deprived or experienced laminae, there was label over terminals that contained mitochondria and round synaptic vesicles and that made asymmetric contacts with dendritic profiles. However, the terminals of deprived afferents differed from those of experienced afferents: They were 25% smaller, contained 33% fewer mitochondria, were more likely to make synapses that were presynaptically convex (and thus, perhaps, immature), and synapsed onto smaller spines. These morphological changes were greater for afferents to upper layer IV than for afferents to lower layer IV. The geniculocortical synapses from deprived laminae were also reduced in number. To correct for variations in injection size and for a probable reduction in protein synthesis by cells in the deprived laminae, I computed the ratio of labeled synaptic terminals to labeled myelinated axons. Injections into the deprived laminae labeled 43% fewer synaptic terminals per labeled myelinated axon than did injections into the experienced lamina. The finding that the synaptic terminals of deprived afferents are both abnormal morphologically and fewer in number can help to explain the reduced effectiveness of the deprived eye in driving cortical cells.
Anatomy and innervation of the anterior aorta of Aplysia and the ultrastructure of specialized neuromuscular junctions on vascular smooth muscle
Authors: Price Christopher H. , Fowle William , Rittenhouse Ann R. 
Published: January 2005

AbstractThe fine structure of the cellular layers and innervation of smooth muscle in the anterior aorta of Aplysia were examined. The inner layer of circular muscle is not innervated but its fibers may be electrically coupled. In contrast, longitudinal fibers in the outer layer are well separated and richly innervated by highly specialized neuromuscular junctions (NMJ). Three distinct types of NMJ are present on this smooth muscle, each identifiable by a set of quantitatively described morphological features including size, degree of contact with sarcolemma, density of active zones, number of mitochondria and vesicular content. The three types of NMJ are likely to arise from the identified serotonergic (RDAAE), cholinergic (RDAAI), and glycinergic (R14) neurons that provide the major known excitatory, inhibitory, and modulatory inputs to this vessel. Each longitudinal muscle fiber is separately innervated by one or more NMJ of each type. Since there are no intercellular junctions between longitudinal fibers, coordination of contractility is clearly a function of the pattern of neural activity. This report further characterizes the rapid and fine control of the vasculature in Aplysia and demonstrates the utility of this preparation for cellular‐level studies on the neural control of smooth muscle and neurochemical messengers mediating its activity.
The organization of projections from the cortes, amygdala, and hypothalamus to the nucleus of the solitary tract in rat
Authors: van der Kooy Derek , Koda Leonard Y. , McGinty Jacqeline F. , Gerfen Charles R. , Bloom Floy E. 
Published: January 2005

AbstractDirect 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.We suggest that direct projections to the NTS and dorsal motor nucleus of the vagus are one criterion that can be used to define the visceral fore‐brain. The organization of the forebrain terminations in the solitary complex described here may eventually allow a better understanding of how the brain controls visceral function.
The development of photoreceptors in the zebrafish, Brachydanio rerio. II. Function
Authors: Branchek Theresa 
Published: January 2005

AbstractThe functional development of rod and cone photoreceptors in the zebrafish (Brachydanio rerio) was studied by electroretinographically measuring flicker fusion frequencies. Two to 3 days after fertilization, fish gave little or no response to high intensity stimuli. Increases in sensitivity and flicker resolution were observed after this time. Biphasic response curves typical of adults could be elicited from fish as young as 2 weeks postfertilization, thus indicating a functional divergence of rods and cones. The results are consistent with behavioral and anatomical analyses of zebrafish photoreceptor development.
Subcortical projections of the inferior parietal cortex (area 7) in the stump‐tailed monkey
Authors: Weber Joseph T. , Yin Tom C. T. 
Published: January 2005

AbstractThe efferent projections of the neocortex on the lateral convexity of the inferior parietal lobe (area 7 of Brodmann) were examined using the anterograde transport of tritiated amino acids. Multiple injections of 3H‐leucine and 3H‐proline were placed within the three cytoarchitecturally distinct zones that lie along the exposed surface of the inferior parietal lobe (IPL). The subcortical projections resulting from these injections were studied. Prominent projections were seen in the thalamus (medial and lateral pulvinar), brainstem (dorsolateral and ventral pontine nuclei), and basal ganglia (caudate and putamen) with less dense label over the thalamic intralaminar nuclei, pretectal complex, superior colliculus, reticular nucleus of the thalamus, suprageniculate nucleus, lateral posterior nucleus, oral pulvinar, and claustrum. In many of these cases there was a topographical relationship apparent with regard to the injections placed along the rostral‐caudal dimension of the IPL. There is a striking reciprocal arrangement in the afferent and efferent projection systems of the IPL. The functional relevance of both the topography and the efferent projections of the IPL is discussed.
Torpedo electromotor system development: A quantitative analysis of synaptogenesis
Authors: Fox Geoffrey Q. , Kötting Dieter 
Published: January 2005

AbstractSynaptogenesis in the electric organ of Torpedo marmorato has been studied quantitatively at the ultrastructural level of observation. In addition to establishing the normal developmental time course for this event we were interested in determining whether a gradient of synaptogenesis might be present because the electric organ produces several morphologically recognizable spatiotemporal gradients during its early ontogeny. These gradients genesis of electrocyte columns, both gradients of which are operative for periods of weeks. No gradient of synaptogenesis was found, indicating this to be a synchronous process. The idea is advanced that synaptogenesis in the electric organ is modulated by extrinsic influences, many of which may originate from the target electrocytes which, by this time, have became synchronized in their development.