bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mudpuppy retinal ganglion cell morphology revealed by an hrp impregnation technique which provides golgi‐like staining
Authors: Arkin Martin S. , Miller Robert F. 
Published: January 2005

AbstractA new technique of retrograde labeling of ganglion cells with horseradish peroxidase (HRP) has been developed, based on orbital injections of HRP combined with a detergent (lysolecithin). When injections are followed by an appropriate survival time, dense staining of a small number of widely scattered cells results in Golgi‐like filling of each neuron. This technique, as well as a variation which causes mass staining of ganglion cell somas, has been used to analyze the morphology of mudpuppy retinal ganglion cells. Morphological analysis has relied on computer reconstruction techniques for display, analysis of dendritic sublamination pattern, and morphometric analysis of the dendrites and soma.Based on morphological criteria, the mudpuppy retina contains a rich variety of ganglion cell types which vary according to soma placement, dendritic field size, polar vs. non‐polar dendritic fields, dendritic branching pattern, and dendritic sublamination. The mudpuppy retina contains both conventional and displaced ganglion cells: the latter constitute about 15% of the total ganglion cell population. Both conventional and displaced ganglion cells show morphological diversity of dendritic sublamination branching pattern; cells from each group have a dendritic branching pattern confined to either distal or proximal divisions of the inner plexiform layer, whereas other cells have dendrites which branch in both sublaminae. Using morphological criteria, two subtypes of ganglion cells were identified, which have a distinctive branching pattern and dendritic tree size.The size and distribution of ganglion cell somas were analyzed from retinas in which mass staining of ganglion cells was present. The total number of ganglion cells was estimated at approximately 14,500 cells per retina. There was a tendency for soma size and density to decrease near the optic disk. The somas of displaced ganglion cells are smaller than their conventional counterparts, at the same retinal eccentricity.The somas of all HRP filled cells swell when compared to those of unstained fixed and freshly dissected retinas. The degree of swelling is proportional to the length of exposure to HRP. Cell swelling was evident for both retrograde labeling and intracellularly injected HRP. This artifact of HRP staining could influence the interpretation of studies in which quantitative differences in soma sizes are based on the use of HRP labeling.
Parasagittal organization of mossy fiber collaterals in the cerebellum of the mouse
Authors: Heckroth J. A. , Eisenman L. M. 
Published: January 2005

AbstractWe have observed that WGA‐HRP injections in lobule VIII of the mouse result in the labeling of mossy fiber terminals in the anterior lobe (lobules I‐V), which are distributed in five distinct parasagittal bands. Injections in the anterior lobe label mossy fiber terminations in lobules VIII and IX. We interpret these results as indicating that an extensive system of mossy fiber collaterals exists between the anterior lobe and lobule VIII (less so to IX), which terminates as discrete parasagittal bands in the anterior lobe. Intermediate bands are thus occupied by fibers that do not send collaterals to the posterior vermis (VII–IX).In an attempt to identify the source(s) of this collateral system we have used double retrograde tracing techniques. Following injections of one tracer in the anterior lobe and another in lobule VIII we observe large numbers of double retrogradely labeled neurons in the lateral reticular nucleus, the basilar pontine nuclei, and the spinal cord. Thus, these mossy fiber sources are the most likely origins for the banded collateral system. Our studies do not allow us to distinguish whether one, or more than one, of these regions contribute to the system.
Central distribution of the efferent cells and the primary afferent fibers of the trigeminal nerve in Pleurodeles waltlii (Amphibia, urodela)
Authors: Gonzalez Agustín , Muñoz Margarita 
Published: January 2005

AbstractAs part of a study on the organization of the brainstem in a primitive group of vertebrates, the efferent cells and primary afferent fibers of the urodele amphibian Pleurodeles waltlii were examined by means of retrograde and anterograde axonal transport and anterograde degeneration. The trigeminal motor nucleus is located in the periventricular gray just medial to the sulcus limitans. Its rostral part is a band of pear‐shaped cells lying parallel to the wall of the ventricle, whereas its caudal part is a round mass consisting of polygonal cells. In addition, a small group of scattered neurons is situated ventral to the rostral part of the nucleus. The primary afferent fibers enter the brainstem in the dorsal two‐thirds of the trigeminal root. They diverge into a short ascending and a long descending tract. The former distributes its axons to the principal sensory trigeminal nucleus, which is an ill‐defined cell group located at the ventrolateral edge of the periventricular gray. In the descending tract, the fibers of the ophthalmic nerve are predominantly located ventromedially, and those of the maxillomandibular nerve dorsolaterally. A fascicle of the ophthalmic nerve leaves the descending tract and, apparently, makes contact with the accessory abducens nucleus. The descending tract extends caudally into the three upper cervical segments of the spinal cord. The mesencephalic trigeminal nucleus consists of conspicuous large cells, which are scattered through the tectum of the mesencephalon. The cells with peripheral branches in the ophthalmic nerve are mainly located in the caudal half of the tectum, and those with peripheral branches in the maxillomandibular nerve in the rostral half Collaterals of the central branches of the mesencephalic trigeminal system were traced to an area of the periventricular gray situated between the motor nucleus and the principal sensory nucleus of the trigeminus.
Morphometric study of the glomerular population in the mouse olfactory bulb: Numerical density and size distribution along the rostrocaudal axis
Authors: Royet J. P. , Souchier C. , Jourdan F. , Ploye H. 
Published: January 2005

AbstractA morphometric study of the glomerular population in the olfactory bulb of the mouse has been carried out by using stereological methods. On the basis of the assumption that the glomerular population is a polydispersed system of spheres, glomerular profile distributions obtained from profile measurements were subjected to a mathematical unfolding procedure to obtain the actual glomerular size distribution. We used a distribution‐free method to account for the combined effects of overprojection due to section thickness and truncation (two missing profile mechanisms). Results proved better than those obtained directly from profile measurements without stereological analysis. Several new findings were obtained. First, significant variations of the glomerulus sizes were found along the rostrocaudal axis. The glomeruli are larger in the middle region of the olfactory bulb, whereas their numerical density decreases in the same region. Moreover, the profile density is homogeneous along the rostrocaudal axis. In other words, the relative surface occupied by the periglomerular cells in the glomerular layer is invariant. As a consequence, it may be concluded that the variations in size and numerical density are inversely correlated. Thus, since the glomeruli are larger in the middle region, their number per unit volume is logically smaller in this same area. Finally, the computerization of all these data has led us to estimate the number of glomeruli (1,810 ± 41) in the olfactory bulb of the mouse. In order to get a comparative idea of their advantages and disadvantages, other standard stereological methods were used in the present study to determine this number. Functional interpretations of the variations of the size and numerical density along the rostrocaudal axis of the olfactory bulb are discussed with respect to ontogenetic and morphofunctional data obtained elsewhere.
Collateral reinnervation of taste buds after chronic sensory denervation: A morphological study
Authors: Kinnman Erik , Aldskogius Hårkan 
Published: January 2005

AbstractPeripheral transganglionic transport of horseradish peroxidase (HRP) was used to label afferent fibers in the taste buds and lingual epithelium 2–12 weeks after chronic chorda tympani or combined chorda tympani‐lingual nerve lotions, From 4–12 weeks after a chronic chorda tympani lesion, taste buds could be found. These were innervated by fibers from the ipsilateral lingual nerve. From 8–12 weeks after a. chronic chorda tympanivlingual nerve lesion, nerve fibers from the contralateral lingual nerve could be found in a few taste buds on the denervated side of the tongue. Thus, collateral sprouting took place over the midline in this instance. These findings indicate that intact gustatory axons do not sprout into denervated taste buds, but trigeminal fibers in the lingual nerve do have this ability.
A Golgi‐electron microscopic study of fusiform neurons in the hilar region of the dentate gyrus
Authors: Ribak Charles E. , Seress László 
Published: January 2005

AbstractThe fusiform cells of the dentate gyrus are located in a portion of the hilus within 100 μm of the granule cell layer. They have ovoid somata and bipolar dendrites that generally run parallel to the granule cell layer. The dendrites of these cells are either spiny or sparsely spiny. The spiny fusiform cell has numerous spines along its dendrites, which are contacted by terminals with the features of granule cell axon collaterals. This cell type also displays somal spines that are contacted by similar terminals. In contrast, the sparsely spiny fusiform cell displays only a few spines, which are contacted by multiple small axon terminals that synapse with both the stalk and end bulb of the spine. Most synaptic input for this cell type is made with the smooth surfaces of the soma and dendrites. A variety of terminals form synapses with the sparsely spiny fusiform cell, including terminals that resemble the fine axon collaterals of mossy fibers. The somata of these two cell types also display differences in the amount of Nissl bodies and the degree of nuclear infolding.The results indicate that spiny fusiform cells are similar to mossy cells, another hilar cell type that receives its major synaptic input from axon collaterals of mossy fibers from granule cells. The distribution of the dendrites of spiny fusiform cells and the pattern of granule cell axon collaterals suggest a high degree of convergence from granule cells. In contrast, the variety of axodendritic synapses for sparsely spiny fusiform cells suggests that more diverse inputs affect this cell's activity. Therefore, the structure and circuitry of these two hilar cell types are probably different. This study adds further evidence to indicate that the hilus contains a large variety of cell types with different neuronal connections.
Representation of the forepaw in the feline cuneate nucleus: A transganglionic transport study
Authors: Nyberg Gunnar 
Published: January 2005

AbstractThe projection of forelimb nerves innervating the paw to the cuneate nucleus was studied in the cat by the transganglionic transport method. Exposure of a single digital nerve to the tracer (a conjugate of horseradish peroxidase to wheat‐germ agglutinin) resulted in a longitudinal sequence of labeled patches throughout the extent of the nucleus. In the middle region the labeled patches coincided with the location of the cell clusters that are characteristic of this part of the nucleus. A very precise somatotopic termination pattern was found in the middle region of the nucleus. Afferent fibers from the palm were represented superficially close to the dorsal rim. The digits were represented in a mediolateral sequence, with the first digit in the dorsolateral part of the nucleus and the fifth digit in the dorsomedial part. The ventral surfaces of the digits were represented superficial to the dorsal surfaces. The dorsum of the paw was represented close to the center of the nucleus. A similar somatotopic organization, but much less detailed, was found in the rostral and caudal regions of the cuneate nucleus. These dissimilarities in somatotopic detail between the different cytoarchitectonic regions of the cuneate nucleus probably reflect differences in function between these regions.
Origin of sympathetic and sensory innervation of the elbow joint in the rat: A retrograde axonal tracing study with wheat germ agglutinin conjugated horseradish peroxidase
Authors: Widenfalk B. , Elfvin L.‐G. , Wiberg M. 
Published: January 2005

AbstractAfter injection of wheat germ agglutinin conjugated horseradish peroxidase (WGA‐HRP) into the elbow joint of adult rats, labeled neurons were found in the stellate and the T2‐T4 ganglia of the ipsilateral sympathetic trunk, and also in dorsal root ganglia at the C4–T4 levels. Most labeled sympathetic cells, 90% or more, were located in the stellate ganglion. The sensory innervation to the joint originated mainly from the dorsal root ganglia at the levels of C7–T1.
Studies of the early stages of optic axon regeneration in the goldfish
Authors: Lowenger E. , Levine R. L. 
Published: January 2005

AbstractWe have studied the early stages (4–14 days) of axonal regeneration following intraorbital optic nerve crush in the goldfish. We used 3H‐proline autoradiography to anterogradely label and visualize the growing axons and wheat germ agglutinin–conjugated horseradish peroxidase (WGA:HRP) for retrograde labeling to determine the cells of origin of the earliest projections.The first retinal ganglion cells (RGCs) that could be retrogradely filled from the optic tract, following optic nerve crush, were in the central retina and were seen at 8 days postoperative. More peripheral cells were only labeled with longer postcrush survival periods. Thus, the first axons to regenerate past the lesion were from central RGCs. The axons of these cells extended into the cranial nerve stump between 4 and 5 days postcrush and entered the nerve as a fascicle, which travelled just beneath its surface. Studies of nerve cross sections from animals at 5–8 days postoperative demonstrated that initial outgrowth was not confined to any particular locale within the nerv although the early fibers appeared to avoid its temporal aspect. When the regenerating axons reached the optic tract they remained in fascicles but left the surface to run along the medial, deep portion of the tract, immediately adjacent to the diencephalon and pretectum.The positions occupied by the earliest‐regenerating axons in the optic nerve were variable and not always appropriate for their central retinal origin. However, the abrupt change in growth trajectory as the fibers entered the optic tract brought them into the areas of the visual paths that are occupied by central axons in intact animals. We suggest that this change in position is related to both changes in the structural organization of the intracranial visual paths and to possible axon guidance signals in the region of the nerve‐tract juncture.
Patterns of angiogenesis in neural transplant models: II. Fetal neocortical transplants
Authors: Krum Janette M. , Rosenstein Jeffrey M. 
Published: January 2005

AbstractVascular integration between transplanted fetal CNS tissues and host brain is essential for long‐term transplant survival. This study compares the time course and mechanism of vascularization in allografts of fetal cerebral cortex inserted either into the fourth ventricle or directly into the parietal cortex or hippocampus of perinatal rats. Recipient animals were administered 3H‐thymidine after various postoperative time periods. The tissues were processed for light microscopic autoradiography to determine the temporal pattern of endothelial proliferation at the graft sites. Correlative electron microscopy depicted the morphological changes in transplant vasculature. Some recipients were prelabelled with 3H‐thymidine prior to transplantation to determine if host vessels invaded the grafts; conversely, some donor tissues were prelabelled in utero to ascertain if the intrinsic vascular anlagen survived.Intraventricular transplants contained patent vessels, probably originating from the host pia mater, as early as 24 hours postoperative. Intraparenchymal transplants had patent vessels by 72 hours and a more complete network by 5 days. Prelabelling experiments and ultrastructural observations demonstrated that adjacent host pial vessels became incorporated into the perimeter of the intraventricular transplants and later grew centrally into the grafts. Intraparenchymal transplants also contained host vessels that exhibited a similar growth pattern. Intrinsic graft vessels remained viable and continued their development, and presumably anastomosed with the ingrowing host vasculature. Temporal labelling studies revealed that both vessel populations attained their highest proliferative rates within 72 hours after transplantation.This study demonstrates that the vasculature which develops within both intraventricular and intraparenchymal fetal CNS transplants is chimeric, consisting of intrinsic fetal vasculature and proliferating host vessels. The mechanism of transplant vascularization may be significant with regard to astrocytic, immunological, or blood‐brain–barrier characteristics at these transplantation sites.
Quantified regional and laminar distribution of the noradrenaline innervation in the anterior half of the adult rat cerebral cortex
Authors: Audet Marie Andrée , Doucet Guy , Oleskevich Sharon , Descarries Laurent 
Published: January 2005

AbstractThe regional and laminar distribution of the noradrenaline (NA) innervation in the adult rat cerebral cortex was quantified in radioautographs of semithin sections from whole hemisphere slices incubated with tritiated catecholamines and a monoamine oxidase inhibitor. Uptake‐labeled axonal varicosities (aggregates of silver grains) were counted with the help of a computerized image analyzer in seven cytoarchitectonic areas of the rostral half of the cortex: Cg3, rostral AID, Cg2, Fr1, Par1, caudal AID, and Pir (prepiriform) according to Zilles's nomenclature. Both dopamine (DA) and NA terminals were detected after incubation with [3H]DA and citalopram or with [3H]NA alone. In the presence of desipramine (DMI), DA terminals alone were demonstrated; the number of NA terminals was then obtained by subtraction from counts in adjacent slices incubated with or without DMI. These counts suggested that DA and NA varicosities were fully visualized only after labeling with their respective tritiated amine. Similar numbers of labeled NA varicosities as inferred after [3H]NA incubation with or without DMI were observed after [3H]NA incubation in the presence of benztropine (BZ). This indicated that NA terminals were then maximally detected to the exclusion of the DA ones, and the latter approach was adopted for the acquisition of normative data. Since the average diameter of the labeled NA varicosities was known from earlier measurements in electron microscope radioautographs, the initial counts of labeled sites/mm2 of histological section could be expressed as numbers of varicosities/mm3 of tissue following a double correction for incomplete detection at the chosen duration of radioautographic exposure and section thickness. The overall density of NA innervation was thus estimated at 1.2 million varicosities/mm3 of tissue, with no statistically significant differences between the seven cortical areas examined. In every region, the number of NA terminals was the greatest in the molecular layer (1.5–2 times the density in the rest of cortex) and then progressively decreased in the underlying cortex, with a two‐ to threefold difference between upper and lower layers. These numerical data allowed an estimation to be made of the possible number of cortical NA varicosities per locus coeruleus nerve cell body of origin (at least 300,000), of their average number per cortical neuron (30–50), their actual incidence among all terminals in the cortex (1/1,000), their mean endogenous amine content per varicosity (0.22 fg), and the mean number of recognition sites for the uptake blocker DMI (4,500/varicosity). Further quantification of the cortical NA innervation in correlation with these and other measurable parameters of Na function under physiological or experimentally altered conditions should improve our understanding of the properties and role(s) of this monoamine in cerebral cortex.
Maturation of rat visual cortex: IV. The generation, migration, morphogenesis, and connectivity of atypically oriented pyramidal neurons
Authors: Miller Michael W. 
Published: January 2005

AbstractThe generation, migration, and morphogenesis of atypically oriented pyramidal neurons in the rat visual cortex were examined. In the mature cortex, these neurons were distributed through layers II–VI. Moreover, the atypically oriented pyramidal neurons in a particular layer tended to be oriented in a specific way; atypically oriented pyramidal neurons in layer II, layers III–VIa, and layer VIb were obliquely, radially, and obliquely oriented, respectively. Ultrastructurally, the somata of atypically oriented pyramidal neurons contained large euchromatic ovoid nuclei and cytoplasm that was replete with rough endoplasmic reticulum and Golgi apparatus. These somata formed only symmetric axosomatic synapses. Many atypically oriented pyramidal neurons projected axons into the white matter as demonstrated by a Golgi method and by a retrograde tract‐tracing technique; however, some of these pyramidal neurons in layers III–V had axons that ascended to layer I.By using a technique which combined retrograde tract tracing with [3H]thymidine autoradiography, it was determined that most atypically oriented pyramidal neurons in layers V and VIa, layer IV, and layer II were generated on gestational days (GD) 15–17, GD 17–19, and GD 20–21, respectively. Atypically oriented pyramidal neurons were identified during the period from postnatal day 0 (day of birth) to day 30. On day 0, obliquely oriented pyramidal neurons were distributed in the deep cortical plate, i.e., immature layer VI. On day 3, the youngest atypically oriented pyramidal neurons were radially oriented and were located in layer IV. Some obliquely oriented pyramidal neurons were present in layer II on day 6, but the greatest number and the most severely canted pyramidal neurons in layer II were evident on day 9. The orientations of the cell body and the apical dendrite did not change appreciably after migration was complete, except for those in layers V and VI with obliquely oriented cell bodies and radially oriented apical dendrites. The second and third postnatal weeks were marked by substantial morphological differentiation of all pyramidal neurons as noted by the lengthening and branching of dendrites and by the appearance of dendritic spines. By the fourth postnatal week, atypically oriented pyramidal neurons achieved their mature morphology.The generation, migration, and morphogenesis of atypically oriented pyramidal neurons proceed by an inside‐to‐outside sequence. This development is similar and concurrent with that of typically oriented pyramidal neurons.