bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative anatomy of the distribution of catecholamines within the inferior olivary complex from teleosts to primates
Authors: Kamei Ichiro , Shiosaka Sadao , Senba Emiko , Takagi Hiroshi , Sakanaka Masahiro , Inagaki Shinobu , Takatsuki Kenichi , Nakai Kunio , Imai Harumichi , Itakura Toru , Komai Norihiko , Tohyama Masaya 
Published: May 2005

AbstractThe distribution of catecholamine (CA) in the inferior olivary complex (IO) of various vertebrate (from fish to monkey) was investigated by means of the histofluorescence technique. In addition, using rats, a further attempt was made to elucidate the origins of CA in the IO.The IO of the lower vertebrates (from fish to birds) was in general poorly innervated by the CA neuron system. IO in the lower mammals, such as insectivora and bats, contained only a few CA nerve terminals, while that in the higher mammals such as rat, guinea pig, rabbit, cat, and monkey revealed quite a number. In these animals, species‐specific patterns of CA nerve terminals were found. In the rat, the highest concentration was observed in the dorsal lamella of the principal nucleus and in the guinea pig ventral lamella. In the rabbit and cat, maximum CA nerve terminals were detected in the dorsal accessory nucleus, while in the monkey, they were detected in the medial accessory nucleus.The retrograde tracer technique of horseradish peroxidase (HRP) suggested that the main source of the abundant CA terminals in IO of the rat might be A1, A2, and A3 noradrenaline neurons, though not locus coeruleus and not dopaminergic ones.
Structural diversity of marginal (Lamina l) neurons in the adult monkey (Macaca mulatta) lumbosacral spinal cord: A Golgi study
Authors: Beal John A. , Penny Joseph E. , Bicknell H. Ryan 
Published: May 2005

AbstractUtilizing the Golgi technique, the present study provides a structural analysis of primate marginal (lamina I) neurons in the lumbosacral spinal cord. Marginal neurons are classified on the basis of major structural differences in dendritic conformation, distribution, and specialization. Cell size and shape alone were not found to be reliable criteria. Marginal cells can be divided into four major groups. Group I (Aspiny Neurons with Thick, Blunt Dendrites) consists of neurons with relatively thick dendrites which have an abrupt, blunt termination and few spines. This heterogeneous group includes large, medium, and small neurons of various shapes. Group II cells (Large to Medium Spiny Neurons) can be subdivided into two distinct groups: Group IIA neurons, which have longitudinal spiny dendritic arbors, and Group IIB cells, which have a moderately spiny, fan‐shaped dendritic arbor which spreads across the lateral portion of the dorsal marginal zone. Both Groups A and B exhibit several types of spines. Group III (Aspiny Neurons with Thin, Tapering Dendrites) consists of small to medium size neurons which can be further divided into two groups: Group IIIA, which is characterized by oval‐ to fusiform‐shaped neurons with tortuous, fine, tapered dendrites which ramify in the dorsolateral fasciculus and the lateral funiculus, and Group IIIB, which is composed of fusiform‐, pyramidal‐ and polygonal‐shaped neurons with fine, tapering dendrites confined to lamina I. Group IV (Small Spiny Neurons) are characterized by a small fusiform‐to pyramidal‐shaped cell body and delicate longitudinal dendrites with small, short‐necked pedunculated spines. This group is subdivided into Group IVA cells, which are found within lamina I proper and Group IVB cells, which are located in the dorsolateral fasciculus and have unmyelinated axons.The present study demonstrates considerably more structural diversity within the marginal zone than has been previously reported, and offers sufficient variation to correlate with functional differences described for lamina I neurons.
Rules of motor innervation in chick embryos with supernumerary limbs
Authors: Hollyday Margaret 
Published: May 2005

AbstractThe positions of motoneurons supplying individual muscles in chick embryos with grafted supernumerary limbs have been identified using retrograde transport of horseradish peroxidase. For a given muscle, motor pool location varied depending on the embryonic origin of the muscle, the position of the limb along the rostrocaudal axis of the body, and the limb's orientation with respect to the body wall. Limb muscles derived from the ventral part of the embryonic premuscle mass were always innervated by medially located motoneurons. Muscles derived from the dorsal portion were consistently innervated by motoneurons in either intermediate or far lateral positions. These relationships were invariant with changes in limb position and orientation. These findings indicate that motor axons can recognize and selectively innervate muscles derived from either dorsal or ventral muscle mass.In addition, the spinal nerves innervating each limb were identified. The type of limb plexus (e.g., crural, sciatic, or wing) and the peripheral branching patterns of the nerves within the limbs were also studied and found to be controlled by the limbs. The rostrocaudal variation in motor pool position similarly depended on the position and orientation of the limb. This rostrocaudal variation in motor pool position can be explained by the limb's ability to determine axonal outgrowth pathways and hence to constrain the possible target choices of outgrowing axons.The process of limb innervation involves interactions between motoneuron axons having intrinsic differences or specificities, and the character of the local environment of the limb into which they grow.
Neuronal and neuroglial responses following retinal lesions in the neonatal rats
Authors: Miller Nancy Muchnick , Oberdorfer Michael 
Published: May 2005

AbstractLesions were produced in the nasal‐superior quadrant of rat retinas at 1 day postnatal. Both the optic fiber and ganglion cell layers were destroyed at the lesion site. Retrograde changes in the more peripherally located ganglion cell bodies, their optic fibers, and neuroglia were monitored by light and electron microscopy. No optic fibers remained in the region peripheral to the lesion site after 2 days postoperative (DPO). Neither regenerative sprouting nor axonal ingrowth from late‐maturing ganglion cells in the retinal periphery was observed. Cell death of the large and the majority of medium ganglion cell bodies was very rapid, as was clearing of the degeneration products. These processes peaked at 1 DPO and were complete by 2 DPO. Microglia and Mueller cell cytoplasm actively phagocytized degenerating ganglion cell bodies and their optic fibers.A stable population of cell bodies in the ganglion cell layer peripheral to the lesion remained intact from 2 DPO to 21 DPO. The surviving somata were consistently 65% of the control ganglion cell population, and they remained after their axons had degenerated. The cell bodies measured 6–12.1 m̈m in diameter, a range which included the small cell population and a few of the medium cells. Dendritic patterning, used to designate ganglion cell types, corroborated their classification as small and medium ganglion cells. Morphological changes in these perikarya due to axotomy were limited to a mild chromatolytic response.
Axonal guidance during development of the optic nerve: The role of pigmented epithelia and other extrinsic factors
Authors: Silver Jerry , Sapiro Jacob 
Published: May 2005

AbstractIt is well established that a congenital lack of ocular melanin (albinism) can lead to developmental abnormalities of the central visual pathways. However, it is yet unknown how the pigmentation per se acts to influence formation of the optic projection. In order to study the possible interaction between eye pigment and optic axons during development, we have examined, with the use of serial section techniques, a series of timed embryos at stages when the ocular pigment and outgrowing axons first become apparent. Our results have demonstrated that, in mice and rats, the upper wall of the distal half of the primitive eye stalk (a region which lies along the potential route to be taken by the earliest developing nerve fibers) is transiently pigmented prior to and during the migration of the pioneer optic axons. All outgrowing neurites avoid this stretch of melanotic tissue and instead grow preferentially through a system of extracellular tunnels in the ventral, pigment‐free zones of the distal eye stalk. The stalk remains unpigmented from about its midpoint and continuing toward the brain. At the pigment/pigment‐free interface many of the axons shift upward from their ventral positions, forming a marginal annulus. In the chick, on the contrary, pigmentation of the stalk does not occur and as the optic axons exit the globe they grow immediately in an annulus configuration. In Xenopus, the entire stalk becomes pigmented and the optic fibers congregate in one discrete bundle of fascicles along the length of the stalk's most ventral margin. These observations suggest that melanin‐producing stalk cells may play a role in controlling the topographic patterning of optic fibers within the developing nerve by inhibiting the lateral spread of axonal growth cones into or within their territory. To test this hypothesis we have charted the distribution of optic fibers in the developing optic stalks of timed albino rat embryos. Indeed, as fibers leave the mutant eye, it was found that a small but consistent number of pioneering axons (day E15) become ectopic and immediataely invade nonpigmented regions (those normally pigmented and axon‐free) in the distal optic stalk. Thus, the usual topographic arrangement of the collection of pioneer optic fibers is altered in the albino.
Ipsilateral corticocortical projections related to binaural columns in cat primary auditory cortex
Authors: Imig Thomas J. , Reale Richard A. 
Published: May 2005

AbstractProjections from the high‐frequency representations of auditory cortical fields A and P were autoradiographically labeled using anterograde transport of a mixture of tritiated proline and leucine. A single injection of isotope into either cortical field resulted in multiple regions of dense labeling within ipsilateral AI. As the result of an injection of radioactive label into field A in one experiment, densely labeled regions were found to be systematically related to the binaural map throughout the high‐frequency representation of AI. Contralateral dominant suppression responses were located in regions of dense labeling while summation responses were located in regions of less dense labeling. In contrast, it was previously found that callosal axon terminations were more densely concentrated in summation columns than in contralateral dominant suppression columns (Imig and Brugge, '78). Thus, the two classes of binaural columns differ with respect to the density of innervation they receive from these ipsilateral and contralateral populations of neurons.In other experiments in which isotope was injected into field A, a systematic relationship between density of ipsilateral labeling and binaural response class was only seen in a portion of AI; in other regions no relationship was evident. A simple interpretation of these data follows. Within a contiguous territory in field A is a population of neurons whose axons provide more dense innervation to contralateral dominant suppression columns than to summation columns in ipsilateral AI. Injections of radioactivity confined to this territory result in a systematic relationship between the density of labeling and the binaural map throughout AI. Outside this territory is a population of neurons whose axonterminations are not systematically related to the binaural map in AI. Isotope injections which engage both territories may result in a systematic relation between density of labeling and the binaural map in one portion of AI, while in another, no relationship may be evident.There is some indication that projections from field P may also be related to binaural columns in AI in the same manner as are the projections from field A.
Pulpal axons in developing, mature, and aging feline permanent incisors. A study by electron microscopy
Authors: Fried K. , Hildebrand C. 
Published: May 2005

AbstractThe ingrowth, maturation, and aging of pulpal axons was followed by electron microscopy in permanent mandibular incisors of 44 cats aged 35 days–11 years. The first axons entered the incisor pulps about 2 months after birth. Cells resembling Schwann cells, but lacking an axonal relation, were also observed at this time. Axonal ingrowth and maturation continued until 7 months, when the pulps contained 92–394 axons, 81–88% of which were unmyelinated. Between month 7 and 20 months the character of the incisor pulpal axons remained largely unchanged. In adult cats the myelinated pulpal axons had diameters of 1–6 μm. The relation between the number of myelin lamellae and the axon size correlated better with linear + logarithmic than linear functions. The g‐ratios were higher than in most peripheral nerves, and tended to increase with axon diameter. In the old adult this tendency was more evident and the g‐ratios were generally lower. From 3 years on the incisors displayed various age‐related or pathological alterations. These were accompanied by axonal changes and axon loss. In contrast to earlier stages perineriumlike sheaths were frequent in old teeth. The findings are discussed in relation to axon development in the inferior alveolar nerve and in primary incisor pulps.
Developmental growth and degeneration of pulpal axons in feline primary incisors
Authors: Fried K. , Hildebrand C. 
Published: May 2005

AbstractThe life history of pulpal axons in primary mandibular incisors was examined by light and electron microscopy in 56 kittens aged from 25 days postconception to 120 days after birth. Cells resembling Schwann cells preceded the first arrival of pulpal axons, 1 week postnatally. Myelination was initiated during the second week. Two months after birth the incisors were fully grown and each pulp contained about 100 axons. Between 10 and 20% of these were myelinated and ranged in size from 1 to 5 μ. The relation between number of myelin lamellae and axon size appeared nonlinear and differed markedly from that in similarly sized inferior alveolar nerve axons. During the third month many unmyelinated axons showed signs of degeneration. With progress of root resorption an increasing proportion of both unmyelinated and myelinated axons degenerated. In highly resorbed incisors necrotic Schwann cells were associated with degenerating axons and there was a generalized pulpal tissue reaction. In some teeth with advanced root resorption pulpal axons were lacking. A progressive derangement of all pulpal tissue elements continued until shedding during the second half of the fourth month. In incisor nerve branches below the incisor teeth axon degeneration was very limited.
Superior colliculus neurons which project to the cat lateral posterior nucleus have varying morphologies
Authors: Caldwell Ruth B. , Mize R. Ranney 
Published: May 2005

AbstractWe have studied the laminar position, morphology, and synaptic relationships of neurons in the cat superior colliculus which project to the interadjacent division of the lateral posterior nucleus (LPi), using the retrograde transport of horseradish peroxidase. The neurons which project to LPi are remarkably varied in depth, size, morphology, and synaptic density and appear to consist of at least four cell types. Labeled cells were found in four laminae. Forty‐seven percent were found in the superficial gray layer (50–550μm), all but a few within its deep subdivision. Forty‐seven percent were located in the optic layer (550–1,200μm), the majority of these being within the upper one‐half of the layer. Seven percent were found in the intermediate and deep gray layers (below 1,200μm). Cell body area varied widely, ranging from 37 to 768 μm2 (mean of 243μm2). Based on cell size, shape, and dendritic field orientation, we identified four distinct cell morphologies which were labeled. Thirty‐five percent were stellate, 32% were vertical fusiform, 19% were granule, and 12% were horizontal cells. Electron microscope analysis confirmed that neurons projecting to the lateral posterior nucleus are a morphologically diverse group. A sample of 71 labeled cells varied significantly in density of synaptic input as well as in size, shape, depth, dendritic distribution, and cytology.
Quantitative study of synapse formation in the duck olfactory bulb
Authors: Rebiere A. , Dainat J. 
Published: May 2005

AbstractSynaptic emergence and development in the duck olfactory bulb was quantiatively studied by electron microscopy from the 14th day of incubation (E 14) to the adult stage. Overall synaptic density in this bulb grew considerably during the last weeks of embryonic life and the first postnatal week.The pattern of synatpic density development was similar in the four main architectonic layers of the bulb. However, lower density values were observed in the mitral and inner granule cell layers.In the glomerular layer (GL), axodendritic synapse density was always higher than dendrodentritic synapse density. In the external plexiform layer, most synapses were dendrodendritic and were established between the gemmules of the granule cells (GC) and the dendrites of the mitral cells (MC) or tufted cells (TC). Synapses established by MC and TC on GC gemmules, or by GC on MC and TC dendrites had densities very similar to each other at all the stages studied. Reciprocal synapses already appeared at E 14; their density grew until a week after birth (P7) and thereafter remained stable. In the internal granular layer, the density of asymmetrical synapses was always higher than that of symmetrical synapses.Excitatory synapses formed earlier on MC and TC than inhibitory synapses. The ratio of inhibitory‐to‐excitatory synapses rose rapidly after birth, reaching 2.5 in the adult duck. The density of excitatory synapses received by granule cells was as high in the external plexiform layer as in the inner granule layer, at all stages of GC development. However, the ratio of received‐to‐formed synapses fell in these cells from 8.42 at E 14 to 2 after birth. These results are discussed as a function of the evolution of the different synaptic balances during olfactory bulb development.Synaptic development in the duck olfactory bulb at birth is relatively close to the adult state. It appears sufficiently advanced to enable the olfactory system to function in a way compatible with the relatively independent behavior displayed by the duckling.
Afferent sources of a lateral midbrain tegmental zone associated with the pinnae in the cat as mapped by retrograde transport of horseradish peroxidase
Authors: Henkel Craig K. 
Published: May 2005

AbstractA paralemniscal zone in the lateral midbrain tegmentum of the cat has been identified in a possible pathway from the superior colliculus to the facial nucleus that may control pinna movements (Henkel and Edwards, '78). Other brainstem afferent projections to this paralemniscal zone have been mapped in the present study using the retrograde horseradish peroxidase tracing method and are discussed in three groups. First, potential sources of auditory afferents were limited mainly to the external nucleus of the inferior colliculus, the nucleus sagulum, and the dorsomedial periolivary cell group. Labeled cells in other superior olivary regions and the dorsal cochlear nucleus were apparently related to uptake of horseradish peroxidase from the axons of the lateral lemniscus. Second, afferents from several premotor regions involved in aspects of gaze control were identified. These were mainly from the nucleus prepositus hypoglossi and adjacent pontine reticular formation, butalso included projections from the medial vestibular and abducens nuclei and possibly subthalamic regions such as the zona incerta and fields of Forel. Third, a relatively large group of midbrain afferents was closely related to the origin of the collicular projection to the paralemniscal zone. This group consisted of labeled cells in the periaqueductal gray matter, nucleus cuneiformis, and pretectum. The relatively sparse labeling in auditory regions that projected to the paralemniscal zone seems to indicate that the sensorimotor integration necessary to guide pinna movements does not take place primarily in the lateral midbrain tegmentum. The interaction of gaze‐related sources with the pinna‐related pathway is also discussed.
Cholecystokinin in hippocampal pathways
Authors: Greenwood Robert S. , Godar Steve E. , Reaves Troy Albert , Hayward James N. 
Published: May 2005

AbstractThe distribution of cholecystokininlike (CCK‐L) immunoreactive cells and fibers in the rat hippocampal formation and its afferent and efferent connections was studied using the immunoperoxidase technique. In the hippocampal formation CCK‐L immunoreactive perikarya were located in the polymorphic zone of the dentate hilus, all layers of Ammon's horn, the subiculum, the presubiculum, and the entorhinal cortex. Cholecystokininlike immunoreactive fibers extended from cell bodies or were located around the cell bodies in the entorhinal cortex, subiculum and stratum pyramidale of Ammon's horn, and among the granule cells and inner molecular layer of the dentate gyrus. The immunoreactive cells in the stratum oriens may be a type of basket cell, since processes from these cells extend into stratum pyramidale and collections of CCK‐L immunoreactive fibers are seen around cell bodies in stratum pyramidale.Cholecystokininlike immunoreactive fibers were also observed in the alveus, ventral and lateral fimbria, and ventrolateral lateral septal nucleus. Some of these immunoreactive fibers, therefore, belong to either an efferent or afferent hippocampal formation and/or from the hippocampal subcortical nuclei, the supramammillary nucleus, and the dorsomedial hypothalamic nucleus which contain CCK‐L immunoreactive perikarya. The distribution of these immunoreactive fibers in the fimbria and lateral septal nucleus is most consistent with an anteriorly directed efferent hippocampal pathway.
Efferent projections of the medial preoptic nucleus and medial hypothalamus in the pigeon
Authors: Berk Mitchell L. , Butler Ann B. 
Published: May 2005

AbstractThe efferent projections of the medial preoptic nucleus (POM), anterior‐medial hypothalamic area (AM), and the posteromedial hypothalamic nucleus (PMH) in the pigeon were traced by the autoradiographic technique. Similar and differential connections were noted from these regions. Projections from POM and AM‐PMH were traced to nucleus septalis lateralis, nucleus dorsomedialis thalami, nucleus dorsolateralis anterior thalami (pars ventralis), posterior hypothalamic and medial mammillary areas, area ventralis tegmenti (Tsai), central gray of midbrain and nucleus intercollicularis and substantia grisea periventricularis of the midbrain. The density of silver grains in these regions differed with POM and AM‐PMH injections. Other projections were observed exclusively from only one or two of the nuclear regions injected. Connections from POM and the rostral part of AM were seen to the median eminence, neurohypophysis, and the nucleus of anterior pallial commissure. Only cells of the anterior part of AM project fibers to nucleus septalis medialis. In the hypothalamus, projections from POM are concentrated in the periventricular region and in the preoptic‐hypophyseal tract in the extreme lateral hypothalamus, while AM‐PMH projections are heaviest in the medial hypothalamus and lateral preoptic area. A major difference in the connections of PMH from POM is the more substantial PMH projection to the midbrain. A prominent projection courses dorsolaterally and posteriorly from PMH toward nucleus ovoidalis and splits into two pathways: a lateral pathway which heavily innervates n. intercollicularis and the periventricular gray and a ventrolateral projection to the midbrain tegmentum. The projections described above provide anatomical substrates for neuroendocrine, autonomic, and behavioral functions.