bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution and morphology of corticospinal tract neurons in reeler mouse cortex by the retrograde HRP method
Authors: Terashima Toshio , Inoue Yoshiro , Inoue Kaoru , Mikoshiba Katsuhiko , Tsukada Yasuzo 
Published: January 2005

AbstractReeler, a recessive mutation in mice., causes cytoarchitectqnic abnormalities to the cerebral and cerebellar cortices. In normal controls corticospinal (CS) tract neurons retrogradely labelled after HRP injection into the lumbar cord were situated only in layer V (the inner pyramidal layer). In the reeler, by contrast, the labelled CS neurons were scattered diffusely throughout all levels of the corresponding cortical area. In addition to the malpositioning of the somata, the labelled CS neurons in the cortex of the reeler could be divided into two major classes according to their dendritic pattern: typical pyramidal neurons and atypical ones. The typical pyramidal neuron had an apical dendrite projecting from the superior pole of the soma and ascending toward the pia mater and several basal and basolateral dendrites projecting from the inferior pole of the soma. The atypical neurons consisted of six types: (l)inverted, (2)tumbled, (3)bipolar, (4) V‐shaped, (5) hook‐shaped, and (6) superficial polymorphic. The typical pyramidal neurons in the reeler tended to be situated relatively deep in the cortex and the atypical neurons tended to lie relatively superficially in the cortex. The axons of both the typical pyramidal neurons and the atypical ones in the reeler usually extended from the lower surface of the soma or one of the descending dendrites as in the normal control.
The comparative effects of early‐life undernutrition and subsequent differential environments on the dendritic branching of pyramidal cells in rat visual cortex
Authors: Davies Christine A. , Katz Hillary B. 
Published: January 2005

AbstractMale rats were either undernourished or fed normally from birth to day 21, after which time food was made freely available. At 1 month of age littermate pairs from both nutritional groups were housed in either enriched or impoverished conditions for 30 days and then killed for brain measurements. Significant deficits due to undernutrition were observed in the weight and size of the cerebrum, but not in the thickness or area of the visual cortex. Although there were large differences of between 21 and 39% in the number of higher‐order basal dendrites of layers II and III pyramidal cells, and of about 19% in the distal ring intersections, none except the fourth‐order branches and intersections at 100 μm from the cell body approached statistical significance. Changes in cerebral weight and size also occurred as aresult of differential housing, with theenrichedratsshowingincreased values relative to their impoverished littermates. In contrast to the nutritional treatment, differential housing significantly affected cortical thickness and area, as well as basal dendritic branching of the pyramidal cells. Enriched rats had relative increases of 26% in the number of fifth‐order branches and 45–80% in the number of distal ring intersections.
Maturation and recycling of trigeminal motoneurons in anuran larvae
Authors: Barnes Maryann D. , Alley Keith E. 
Published: January 2005

AbstractDevelopment of the trigeminal motor system was analyzed in Rana pipiens larvae and adults. The aim of this investigation was to determine the postmetamorphic fate of the primary motoneurons that innervate the larval jaw muscles. Specifically, we wanted to ascertain whether these neurons were deleted in conjunction with their muscular targets during metamorphosis or reused to innervate the adult jaw muscles. Cell counts and horseradish peroxidase tracer were used to distinguish between these two possibilities.The number of trigeminal motoneurons was relatively constant in premetamorphic and prometamorphic larvae. A small reduction in the cellular complement of the motor nucleus occurred during metamorphic climax, but the majority (≈︁ 90%) of the primary motoneurons were retained from the larval to the adult nervous system. The cell loss may represent motoneurons that innervated specific larval muscles that have no adult successors and thus the entire myoneural unit degenerates. Retrograde tracers indicated that all trigeminal motoneurcns extended axons into the jaw muscles of both premetamorphic larvae and adult frogs. These observations provide further support for the recycling of the trigeminal motoneurons.
Corticotectal terminals in the superior colliculus of the rabbit: A light‐ and electron microscopic analysis using horseradish peroxidase (HRP)‐tetramethylbenzidine (TMB)
Authors: Holländer Horstmar , Schönitzer Klaus 
Published: January 2005

AbstractThe projection from the striate cortex to the superior colliculus was studied light‐ and electron microscopically by means of anterogradely transported horseradish peroxidase and tetramethylbenzidine histochemistry.Labeled boutons were found in the stratum zonale (SZ) and in the stratum griseum superficiale (SGS), not in stratum opticum (SO). There are two maxima of frequency of labeled boutons, one in middle SGS at about 500 μm depth, and a smaller one in upper SGS at about 200 μm depth. Such a bimodal distribution of corticotectal terminals has not been described in any species before. Labeled myelinated axons were found in SGS and SO with a maximal frequency in middle SGS at about 400 μm depth. The myelinated axons in SZ, which are commonly considered to be of corticalorigin, were not labeled.The labeled cortical terminals contained numerous round synaptic vesicles and predominantly dark mitochondria. They formed usually asymmetrical synapses and contacted dendrites, some of which contained synaptic vesicles. Occasionally, labeled boutons were observed which definitely did not belong to the type that is generally considered to be of cortical origin.
Corticopontine remodelling after cortical and/or cerebellar lesions in newborn rats
Authors: Castro Anthony J. , Mihailoff Gregory A. 
Published: January 2005

AbstractThe distribution of corticopontine projections was studied, primarily with the Fink‐Heimer technique, in adult rats which at 2‐3 days of age had sustained unilateral sensorimotor (SMC) or occipital (OC) cortical lesions and in animals that had received neonatal hemicerebellar (HCb) lesions singly or in combination with the neonatal SMC or OC lesions.Neonatal left SMC or left HCb lesions induced an anomalous increase in crossed sensorimotor corticopontine (SMP) projections originating from the right SMC. This increase appeared more dense after cortical lesions as compared to cerebellar lesions and appeared more dense in those animals receiving the combined SMC plus HCb lesions. No alterations in the distribution of SMP fibers were observed after neonatal OC lesions nor were any alterations of occipital corticopontine (OP) fibers observed in any of the neonatal lesion groups.The remodelling of right SMP projections after neonatal left SMC lesions demonstrates an interaction between corresponding pathways originating from opposite sides of the brain and which occurs in response to the partial removal of afferents to pontine gray neurons as a result of the SMC lesions. In contrast, the absence of SMP plasticity after OC lesions, and vice versa, demonstrates the absence of plasticity between pathways which differ anatomically and functiondly.The substantial neuronal loss which occurs within the right PG after neonatal left HCb lesions is believed to influence the increase in crossed SMP fibers coursing from the right hemisphere to the larger left PG. No increase in crossed OP fibers from the right hemosphere was observed in these animals. The increase in crossed SMP fibers after neonatal SMC lesions combined with neonatal HCb lesions is more dense than found in the single lesion groups. These findings suggest that separate mechanisms of plasticity might be operational for each lesion and that these mechanisms may be additive.
The inferior olive of a prosimian primate, Galago senegalensis. II. Olivocerebellar projections to the vestibulocerebellum
Authors: Whitworth R. H. , Haines D. E. , Patrick G. W. 
Published: January 2005

AbstractOlivocerebellar projections to the vestibulocerebellum of Galago senegalensis, a prosimian primate, were studied by using a horseradish peroxidase (HRP) method. Following implants of HRP into the flocculus, labeled cells are found in subgroup d of contralateral medial accessory olive (MAO), while labeled somata are present throughout subgroups c and d after injections of HRP into the nodulus and adjacent parts of the uvula. Labeled cells are also located throughout the dorsomedial cell column (DMCC) and a small contingent of HRP‐filled cells are seen in dorsomedial areas of the ventrallamellae of the principal olivary nucleus (PO) after HRP placements in nodu‐ lus and uvula. Subsequent to injections of paraflocculus, labeled cells are found in subgroup a of MAO, in the lateral bend of PO, and in its ventral lamella (VLPO).Collectively these data indicate a topographically organized projection of olivocerebellar fibers to the flocculonodular lobe and adjacent areas of paraflocculus and uvula. The paraflocculus receives input from subgroup a of MAO, the lateral bend of PO, and VLPO. Subgroup d of MA0 projects to the flocculus and nodulus with a relatively minor contribution to uvula. Neurons in subgroups c and DMCC of MA0 project to specific portions of nodulus and adjacent uvula. These data are in general agreement with those from other species. In contrast to earlier reports, however, this study describes a projection from VLPO to lateral areas of the contralateral nodulus and uvula. A zonal organization of olivocerebellar terminations in the nodulus and ventral portions of uvula is suggested. A medial zone is subdivided into medial and lateral parts which receive projections from subgroups c and d of MAO, and from cells in DMCC, respectively. A more lateral area receives axons from cells in VLPO.
An electron microscopic study of primary afferent terminals from slowly adapting type I receptors in the cat
Authors: Semba K. , Masarachia P. , Malamed S. , Jacquin M. , Harris S. , Yang G. , Egger M. D. 
Published: January 2005

AbstractPrimary afferent fibers transmitting impulses from slowly adapting (SA) Type I receptors in the glabrous skin of the hind paw of the cat were injected intraaxonally in the spinal cord with horseradish peroxidase (HRP).At the light microscopic level, terminal arborizations were observed in the medial dorsal horn extending up to 6 mm rostrocaudally in and near the seventh lumbar segment. Boutonlike swellings labelled with HRP were distributed in clusters in Rexed's laminae III‐VI. There was a tendency for the most dorsal clusters from an individual fiber to be located rostrally and for the most ventral clusters to be located caudally.At the electron microscopic level, a combination of morphometric analysis and serial reconstruction revealed the following: (1) All the boutons labelled with HRP contained predominantly clear, round synaptic vesicles, 40–50 nm in diameter. (2) Labelled boutons (n = 75) had cross‐sectional longest dimensions of 1.72 ± 0.53 μm (Mean ± S.D.), perimeters of 4.95 ± 1.52 μn, and areas of 1.18 ± 0.59 μm2. Their shapes in section varied from rounded to elongated forms. (3) The sizes of labelled boutons decreased significantly and linearly with depth from lamina IV to VI. The shapes of the bouton cross sections also became rounder with depth in the dorsal horn. (4) About 72% of synaptic contacts associated with HRP‐filled boutons were with dendritic spines and shafts; most of these synapses were of the asymmetric type. (5) The remainder (28%) of the appositions were synapselike contacts between labelled boutons and unlabelled structures containing flattened or pleomorphic vesicles, and occasional dense‐cored vesicles. (6) We observed no unequivocal axosomatic contacts made by labelled boutons. (7) The lengths of synaptic appositions with dendritic spines (0.46 ± 0.20 μm) or with dendritic shafts (0.51 ± 0.18 μm) were significantly greater than the synapselike contacts with vesicle‐containing unlabelled structures (0.29 ± 0.09 μm). (8) Complex neuropilar organization was occasionally seen with labelled boutons as central elements, although simpler organizations were much more common.In summary, HRP‐labelled fibers ended predominantly in boutons containing clear, round vesicles forming axospinous and axodendritic synapses. This is consistent with physiological observations of postsynaptic excitation of dorsal horn cells by the primary afferent fibers from SA Type I receptors in the glabrous skin.
An autoradiographic study of the postnatal development of sensorimotor and visual components of the corticopontine system
Authors: Mihailoff Gregory A. , Adams Catherine E. , Woodward Donald J. 
Published: January 2005

AbstractStandard autoradiographic tracing methods which employed intracortical injections of 3H‐leucine were used to describe the time course of development in those components of the corticopontine system which originate in sensorimotor (SM) or visual (VIS) cortices. These studies were performed using male or female pigmented rats ranging in age from 1 to 24 days (birth = day 0). Labeled axons could easily be recognized within the cerebral peduncle at the level of the basilar pons on postnatal day 1 following either an SM or a VIS cortical injection. Labeling over the basilar pontine neuropil suggestive of axonal ingrowth could also be seen on day 1 following SM injections but not until day 3 in cases with VIS injections. During the latter part of the first postnatal week, both SM and VIS axon terminal fields were established in the pontine neuropil in locations generally similar to those described in the adult. However, at this time they occupied a larger area and appeared more diffusely organized than in the adult. Subsequently during the second postnatal week, both SM and VIS projection fields gradually became more focused and circumscribed until by day 16 in the case of the SM system, and day 18 for the VIS projection, an adultlike configuration was attained. At no time during development was there any evidence of a more substantial contralateral projection than that described for the adult. Correlation of these events with previous Golgi observations and ongoing electron microscopic studies of pontine synaptogenesis suggest that the focusing or constriction of corticopontine axon terminal fields might be the result of a selective degeneration process in which the presynaptic (corticopontine axon) and postsynaptic (basilar pontine neurons) elements both play an active role. Furthermore, the absence of a stage in development characterized by an increase in the density of the contralateral component of the projection confirms the interpretation of earlier studies which suggested that the aberrant contralateral corticopontine projections observed following neonatal cortical lesions were the result of sprouting from the intact corticopontine system and not due to failure of retraction in one component of a system which in fact distributes bilaterally for a time during development.
Substance P and catecholaminergic expression in neurons of the hamster main olfactory bulb
Authors: Kream Richard M. , Davis Barry J. , Kawano Teruaki , Margolis Frank L. , Macrides Foteos 
Published: January 2005

AbstractA coordinated series of immunohistochemical and biochemical analyses have been conducted in the hamster to examine the dependence of substance P and tyrosine hydroxylase (TH) expression by second‐order olfactory neurons, and the level of dopamine in the main olfactory bulb (MOB), on the integrity of carnosine‐ and olfactory marker protein (OMP)‐containing primary afferent neurons. Substance P‐like immunoreactivity (SPLI) is localized in external tufted cells and centrifugal afferents of the MOB; TH immunoreactivity has a wider distribution, in external tufted, middle tufted, periglomerular, and deep short‐axon cells as well as in centrifugal afferents. To characterize the SPLI, this material was isolated by guanidine‐HCl extraction and passage over a C18 SEP‐PAK. The SPLI coelutes on HPLC with authentic substance P and, following oxidation, coelutes with substance P sulfoxide. It is sensitive to α‐chymotrypsin and is resistant to trypsin. Thus, the SPLI in the MOB behaves as authentic substance P. Intranasal irrigation with 0.17 M ZnSO4 results in peripheral deafferentation of the MOB for up to 8 months as evidenced by a persistent loss of OMP immunoreactivity and shrinkage of the olfactory nerve layer and glomeruli. By these criteria, the vomeronasal inputs to the accessory olfactory bulb are not destroyed and the spared vomeronasal receptor neurons do not innervate the vacated peripheral projection field in the MOB. The loss of peripheral inputs to the MOB is accompanied by marked and parallel reductions in the incidences of SPLI‐ and TH‐positive second‐order neurons despite an increase in the density of neuronal somata in the glomerular layer. Biochemical quantifications following peripheral deafferentation also demonstrate significant decreases of both substance P and dopamine, together with the expected decrease of carnosine. In contrast, the SPLI and the TH and serotoninlike immunoreactivities in centrifugal afferents as well as the TH immunoreactivity in deep interneurons do not appear to be reduced, and the MOB content of norepinephrine in centrifugal afferents is unaffected. These results collectively indicate that the loss of inputs from the primary olfactory receptor neurons can reduce the levels of at least two different, putatively neuroactive compounds (substance P and dopamine) in at least three classes of second‐order neurons (external tufted, middle tufted, and periglomerular cells). The control of central neuron phenotype by the peripheral olfactory neurons thus appears to be a phenomenon of broad influence. It may play a role in processing chemosensory information as well as offering a system in which to study neuronal plasticity.
The central nucleus of the inferior colliculus in the cat
Authors: Oliver Douglas L. , Morest D. Kent 
Published: January 2005

AbstractThe central nucleus of the inferior colliculus in the cat is distinguished by its unique neuropil. In Golgi‐impregnated material, it is composed primarily of neurons with disc‐shaped dendritic fields arranged into parallel arrays, or laminae, complemented by the laminar afferent axons from the lateral lemniscus. Large, medium‐large, medium, and small varieties of disc‐shaped cells are distinguished on the basis of the size of the dendritic field and cell body size, dendritic diameter, and dendritic appendages. A second major class of neurons in the central nucleus are the stellate cells with dichotomously branched, spherical‐shaped dendritic trees. Simple, complex, and small stellate cells can be distinguished by their size and by the complexity of the dendritic and axonal branching. Laminar afferent axons are recognized by the nests of collateral side branches and the grapelike clusters of terminal boutons – thick, thin, and intermediate‐sized varieties are apparent. Other axon types include local collaterals of central nucleus neurons, some of which are distinguished by their frequent and complex collaterals.In the central nucleus, the configuration of the fibrodendritic laminae, the presence of subdivisions, and the banding of afferent axons suggest levels of organization which are superimposed on the synaptic arrangements of the individual cell and axon types. The laminar pattern, as studied in serial Golgi‐impregnated sections, differs from previous reports. The central nucleus contains subdivisions which can be distinguished by their laminar pattern, different proportions of cell types, and the packing density of the cell bodies and axonal plexus.The patterns of degeneration observed in Nauta‐stained material after lesions of caudal auditory pathways show that thick and fine afferent fibers form dense bands of degeneration separated by sparse, fine‐fiber degeneration. The bands are thicker than individual laminae but smaller than the subdivisions.The intrinsic organization of the neurons and axons, combined with the laminar organization, subdivisions, and banding patterns, each may contribute different aspects to the processing of auditory information in the central nucleus.
α‐Bungarotoxin binding to the myotome and choline acetyltransferase activity in the rabbit embryo
Authors: Grubič Zoran , Tennyson Virginia M. , Chang Hai Won , Kremzner Leon T. , Penn Audrey S. 
Published: January 2005

AbstractWe have previously found incomplete sarcomeres and acetylcholinesterase activity in the myoblasts of the myotome of the rabbit at day 13 of gestation. We now report that an acetylcholine (Ach)‐synthesizing enzyme and the nicotinic receptor are present at this stage as well. A study of the myotome using [125I]α‐bungarotoxin shows that the mononucleated myoblasts have α‐bungarotoxin binding sites before they migrate away to form multinucleated myotubes. Choline acetyltransferase activity and/or a different ACh‐synthesizing enzyme are found at early stages of development, even before the spinal nerve has formed. An ACh‐synthesizing enzyme is present in the notochord, a neural tube‐dorsal root ganglion preparation, as well as in rows of myotomes separated from the latter preparation. Assays of isolated myotomes with very little adherent mesenchyme indicate that the enzyme is located either within the myotome or in its immediate vicinity. Cholinergic components, therefore, are associated with the mononucleated myoblasts of the myotome before they fuse to form myotubes and before they receive their permanent innervation.
The distribution of Timm's stain in the nonsulphide‐perfused human hippocampal formation
Authors: Cassell M. D. , Brown M. W. 
Published: January 2005

AbstractA detailed description is given of the distribution of Timm's staining in the human hippocampal formation. In sections cut transverse to the long axis of the hippocampal formation the same pattern of staining is seen throughout almost all of the structure, i.e., through all the main body except the most caudal region and, following the medial bend made by the long axis, through most of the pes hippocampi. The staining typically filled almost the whole of the hilus of the dentate gyrus and the whole depth of the adjacent stratum pyramidale and stratum lucidum of subfield CA3. Rostrally, staining was traced into the tip of the uncus. Caudally, staining was traced to the inferior surface of the splenium at the apex of the caudal taper of the hippocampus. No staining was found in the gyrus fasciolaris, indusium griseum, or anterior hippocampal rudiment. Except in the medial part of the pes hippocampi, the Timm's staining did not reach the proximal border of the subfield CA1. In some sections of the main body of the hippocampus a narrow, infragranular stain‐free zone was observed in the hilus. In the dentate gyrus of three older subjects, but not in those of three younger subjects, supragranular staining was found. It is argued that the Timm's staining described in this study is specific to the hippocampal mossy fibres. The distribution of the staining is discussed in relation to the boundaries of subfields CA3 and CA2 as delineated by other authors.