bluuebunny/crossref_metadata_2025_split huggingface dataset:
The connections of the trigeminal and facial motor nuclei in the brain of the carp (cyprinus carpio L.) as revealed by anterograde and retrograde transport of horseradish peroxidase
Authors: Luiten P. G. M. , van der Pers J. N. C. 
Published: December 2004

AbstractThe connections of the rostral and caudal parts of the trigeminal and facial motor nuclei in the carp were studied with the horseradish peroxidase technique. Following ionophoretic peroxidase injections in these motor nuclei, retrogradely labeled cells were observed together with anterogradely labeled motor cell processes. Several cellular areas in thalamus, cerebellum and medulla oblongata were shown to project to the V and VII motor nuclei. Labeled cells were found in the inferior lobe and the glomerular complex of the thalamus. In the medulla oblongata, cells in the descending trigeminal nucleus, reticular nuclei and motor nuclei other than those injected were labeled. Besides these conspicuous projections several smaller connections were also found. These findings are discussed on their significance to respiratory function. Anterogradely labeled cellular processes constitute a relatively simple network of fiber connections between the various motor nuclei and the reticular nuclei of the brainstem. This apparently dendritic system of the bulbar motor complex shows a certain degree of similarity to the structure of the motor system in the spinal cord, and might play a role in the coordinated control of the muscular system.
Increased proliferation of neuroglia and endothelial cells in the supraoptic nucleus and hypophysial neural lobe of young rats drinking hypertonic sodium chloride solution
Authors: Paterson Jean A. , Leblond C. P. 
Published: December 2004

AbstractMale rats aged 30 to 35 days were provided with 1.75% sodium chloride solution as drinking fluid for two weeks, to create a chronic increase in plasma osmolality. During this time, the animals and a control group of water‐drinking rats received two injections per day of 1 μCi of 3H‐thymidine per gram body weight to label dividing cells and their progeny. At the end of this period, the animals were sacrificed by aldehyde perfusion. Sections 1 μm‐thick were saved at intervals from a series cut throughout the length of the supraoptic nucleus; these sections and others taken from the caudate nucleus and the neural lobe of the hypophysis were processed for radioautography.Neuronal nuclei and nucleoli were enlarged in the supraoptic nucleus of salttreated rats, in accord with previous work indicative of neuronal enlargement associated with increased protein synthesis and probably enhanced vasopressin production. Furthermore, most axon terminals in the neural lobe were depleted of neurosecretory granules in the salt‐treated group, a fact suggesting increased release of vasopressin.Cell counts in radioautographs of the supraoptic nucleus revealed that 20.6% of the astrocytes were labeled in salt‐treated rats, but only 5.9% in controls, indicating a marked increase in the production of new astrocytes in the treated animals. Also, endothelial cells were more frequently labeled in salt‐treated rats (52.9%) than in controls (17.4%). In the caudate nucleus, by contrast, the labeling percentages of astrocytes or of endothelial cells did not differ between control and treated rats. In the neural lobe, the labelling percentage of pituicytes was 45.8% in treated, but only 3.1% in control animals. The endothelial cell labeling was also greater in treated (46.5%) than controls (23.9%). Thus, in young rats, a period of salt ingestion elicited both an enlargement of supraoptic neurons and an increase in the production of the astrocytes, pituicytes, and endothelial cells associated with these neurons and their processes.
Physiological identification and analysis of dentate granule cell responses to stimulation of the medial and lateral perforant pathways in the rat
Authors: McNaughton B. L. , Barnes C. A. 
Published: December 2004

AbstractStimulation of the dorsomedial or ventrolateral perforant pathways resulted in quantitatively different extracellularly recorded EPSPs in the fascia dentata of the rat. The two potential differed in latency to peak and in width at half amplitude in a manner consistent with the different locus of termination of the two pathways on the granule cell dendrites. Both potentials were able to follow brief stimulus trains of 100 Hz, which suggests that they are monosynaptic. Medially elicited responses had their peak negativity approximately 100 to 180 μm deeper in the molecular layer than laterally elicited responses. Stimulation at short intervals along a dorsomedial to ventrolateral track in the angular bundle yielded a step function rather than a continuum of EPSP peak latency and half‐width, in agreement with Hjorth‐Simonsen's ('72) evidence for the separateness of the two pathways. Both pathways were able to induce granule cell discharge. Laterally elicited spikes, however, were delayed. Stimulation at intermediate locations frequently elicited double spikes from granule cell population. Population spikes elicited by either pathway were inhibited for as long as 100 msec after a single discharge. Both pathways showed facilitation with double stimuli at short intervals, and both showed post‐tetanic potentiation lasting at least 30 minutes. Under conditins where it could be shown that the two pathways at least partially converged onto the same granule cells, the response of one pathway did not increase when long lasting potentiation was induced on the other.
Retinal ganglion cells in the crucian carp (Carassius carassius). II. Overlap, shape and tangential orientation of dendritic trees
Authors: Kock Jan‐Henrik , Reuter Tom 
Published: December 2004

AbstractGanglion cells were studied in methylene blue stained flatmounted retinas. Three categories of cells are described: small (S) and large (L) ganglion cells in the main ganglion cell layer, and large ganglion cells (LD) with somata more or less displaced into the inner plexiform layer. These LD cells have two to four very thick primary dendrites and are identifiable as ganglion cells by their axons.An analysis of published data reveals that the large genglion cells of the crucian carp (types L and LD) have several striking characteristics in common with the large ganglion cells of the dogfish, the frog and the cat: (1) they are selectively stained by methylene blue; (2) they comprise only 2–5% of all the ganglion cells; (3) the large cells can be divided into two or three subtypes, and within each subtype the dendritic trees usually cover the retinal surface with a two‐ or threefold overlap.New ganglion cells are formed from neuroblasts at the retinal margin and most dendrites first grow along this neuroblastic zone. Thus the main dendrites of the L and LD cells tend to be oriented parallel to the margin all around the periphery of a crucian carp retina. Independent of the size of the eye this parallel orientation disappears at the same relative distance from the margin (about one‐third of the distance from the margin to the optic disc). If all L and LD cells are formed at the retinal margin and first develop oriented dendrites, we have to assume that the more randomly oriented dendritic trees in the central retina have undergone a reorganization.
The synaptic organization of the motor nucleus of the trigeminal nerve in the opossum
Authors: Hamos James E. , King James S. 
Published: December 2004

AbstractThe motor nucleus of the opossum trigeminal nerve consists of a main body and a small dorsomedial cell cluster. The cell bodies form a unimodal population with areas that range from 150–2700 μm2. Golgi impregnations reveal that each neuron has three to six primary dendrites which radiate in all planes from the cell body. Within 300 μm from the soma, the primary dendrites divide into secondary branches and these, in turn, bifurcate into thinner distal dendrites. The overall diameter of the dendritic tree often extends as much as 1 mm, with a rare branch leaving the confines of the nucleus to enter the neighboring reticular formation. Somatic and dendritic spines are often present and are either sessile or complex appendage forms.The perikarya and initial dendritic trunks of trigeminal neurons are contacted by four types of presynaptic terminals which cover more than 40% of the membrane. Most endings are 1–3 μm long and contain either spherical (S) or pleomorphic (P) synaptic vesicles. Another, less common, type of bouton is marked by large dense‐core (DC) vesicles. Approximately 8% of the terminals on trigeminal cell bodies are large (2–5 μm) with spherical synaptic vesicles and are always associated with a subsynaptic cistern (C‐boutons). These terminals very often interdigitate with adjacent synaptic endings. S‐, P‐, and C‐boutons synapse on the dendritic tree of trigeminal neurons in the following characteristic pattern: proximal dendrites (greater than 5 μm in diameter) are contacted by all three types of terminals; intermediate‐sized dendrites (between 2.5 and 5.0 μm in diameter) are most often contacted by S‐boutons although P‐boutons are also present; and small, distal dendrites (less than 2.5 μm in diameter) are almost always contacted by S‐ boutons. Both S‐ and P‐boutons contact spines.In order to determine the ultrastructural identity of some of the major afferent systems to the trigeminal motor nucleus, adult opossums were subjected to two different types of lesions. Three and 5 days subsequent to lesions which destroyed most of the trigeminal mesencephalic nucleus, degenerating terminals containing spherical vesicles were found. These endings were S‐boutons on more distal parts of the dendritic tree while on the cell body and proximal dendrites they were C‐boutons. Seven days after a mesencephalic lesion, expanded glial processes approximated the trigeminal cell membrane. Two days subsequent to lesions which transected commissural fibers from the contralateral trigeminal complex, degenerating S‐ and P‐boutons were found in contact with intermediate and distal parts of the trigeminal dendritic tree.
Ultrastructure of normal and degenerating glomerular terminals of dorsal root axons in the substantia gelatinosa of the rhesus monkey
Authors: Knyihar‐Csillik E. , Csillik B. , Rakic Pasko 
Published: December 2004

AbstractThe fine structure of primary sensory terminals within glomerular complexes of lamina II of Rexed (substantia gelatinosa Rolandi) in the spinal cord was investigated in normal adult rhesus monkeys and in monkeys subjected to thoracic or lumbosacral dorsal root transection. Three types “scalloped” primary sensory terminals were distinguished on the basis of their ultrastructural characteristics, size, and distribution of synaptic vesicle population: (1) dense sinusoid axon (DSA) terminals contain mediumsized (42–46 nm and 58–62 nm) and large (80 nm) clear synaptic vesicles; (2) large dense‐core vesicles (LDCV) terminals are equipped with empty synaptic vesicles ranging from 30 to 106 nm, large, (80 nm) and very large, (100 nm) dense‐core vesicles; and (3) regular synaptic vesicles (RSV) terminals contain a homogeneous population of 45–50 nm clear synaptic vesicles.Follwing transection of the dorsal roots, all three types of primary afferents degenerate and become engulfed and phagocytosed by glial cells. However, each type of terminal displays a different mode and tempo of degeneration as seen in monkeys sacrificed 36, 48, and 72 hours following rhizotomy. DSAs follow the osmiophilic degeneration pattern; LDCVs are characterized by a gradual increase in the number of “electron‐dense bodies” and, less frequently, by a progressive osmiophilic process; RSVs exhibit signs of a filamentous degeneration, accompanied by clusters of synaptic vesicles.The three types of terminals are distributed in an overlapping but distinct pattern within posterior horn. Thus DSAs are present in highest numbers in lamina II where they constitute the most frequent terminal type. LDCVs also occur in lamina II in its outer half but are most concentrated in lamina I. RSVs predominate in the deepeer layers of the dorsal horn (lamina III) but are also found in the internal half of lamina II. On the basis of these ultrastructural data and a comparison with afferent profiles impregnated according to the Golgi method, it appears that DSAs and LDCVs correspond respectively to superficial and marginal collaterals of small, thin dorsal root fibers whereas RSVs represnt terminals of deep collaterals from large, thick dorsal root axons.
Differentiation of cerebellar anlage heterotopically transplanted to adult rat brain: A light and electron microscopic study
Authors: Alvarado‐Mallart Rosa Magda , Sotelo Constantino 
Published: December 2004

AbstractPieces of cerebellar primordia from (days 14 or 15 of gestation) E14 or E15 rat embryos were dissected out and transplanted into a cavity of the occipital cortex and underlying hippocampus, over the superior colliculus of 2‐month‐old rats. The host animals were allowed to survive for 2 to 3 months. The cytoarchitectonic and the synaptic organizations were analyzed in 16 of such transplants. Only 4 of the implants established connections with the host brain through several thin peduncles composed of myelinated fibers. The remaining 12 implants survived in an extraparenchymal situation. Independently of its partial linking to the host brain, the graft grew and developed a cerebellar structure composed of nuclear and cortical regions. The latter exhibited normal lamination and foliation, and contained the five categories of neurons which characterize normal cerebellar cortex.Electron microscopic examination disclosed that the synaptic connections normally present in the cerebellar cortex were also formed in the implants with the exception of climbing fibers, which were absent. The cerebellar interneurons kept their normal topographic distribution and gave origin to numerous synapses which maintained their own specificity. Some mossy fibers were present in the granule cell layer at the center of typical glomeruli. However, abnormal synaptic arrangements were also observed within the neuropil of this granule cell layer. They consisted of pseudo‐glomerular formations composed of clusters of tightly packed small axon terminals covered by granule cell dendrites. The origin of these boutons was not established. Since they did not correspond to the classes of presynaptic elements normally synapsing on these dendrites, they constitute a new example of cerebellar heterologous synapses. Their presence could be related to changes in the cellular environment due to the rarity of mossy afferents.HRP tracing experiments, carried out in extraparenchymal transplants, have allowed us to determine that the corticonucleocortical loop of normal cerebellum is also developed in the implants. Nuclear neurons are at the origin of the mossy fibers involved in glomerular formations, whereas Purkinje cells project to the nuclear region. The establishment of these reciprocal connections could determine the functional stabilization of both kinds of cerebellar neurons and thus the long survival of extraparenchymal grafts.These results allow the conclusion that the presence of extracerebellar afferents is not necessary for the organotypic and synaptotypic differentiation of cerebellar anlage.
Inhibitory and excitatory synapses in crayfish stretch receptor organs studied with direct rapid‐freezing and freeze‐substitution
Authors: Nakajima Yasuko , Reese Thomas S. 
Published: December 2004

AbstractCrayfish abdominal stretch receptor organs are innervated by inhibitory (GABA) and excitatory (glutamate) synapses. Previous studies with aldehyde fixation showed that synaptic vesicles in the inhibitory synapse are flat and small, whereas those in the excitatory synapse are rounder and larger. We have reexamined these inhibitory and excitatory synapses by using direct rapid‐freezing and freeze‐substitution in order to preserve synaptic structure closer to its living state. Fine details of synaptic structure appear to be better preserved by this method. Synaptic vesicles in inhibitory as well as excitatory synapses are round, so the conventional flattened shape of vesicles in the inhibitory synapse must depend on some aspect of aldehyde processing. However, the average size of vesicles in the inhibitory synapse is significantly smaller than that of vesicles in the excitatory synapse, so synaptic vesicle size is regarded as having functional significance.
Retinal ganglion cell size groups projecting to the superior colliculus and the dorsal lateral geniculate nucleus in the North American opossum
Authors: Rapaport David H. , Wilson Paul D. 
Published: December 2004

AbstractThe retinal ganglion cells projecting to the superior colliculus (SC) and dorsal lateral geniculate nucleus (LGNd) of the North American opossum (Didelphis virginiana) were studied by using the horseradish peroxidase (HRP). The four ganglion cell size groups recognized previously were found to project in systenatically different ways. After injections of HRP into the superior colliculus, labeled cells were seen in nasal retina contralateral to the injection and in temporal retina both ipsilateral anc contralateral to the injection. In contralateral nasal retina cells of all size classes were labeled, while in contralateeral temporal retina small (8–14 μm diameter), small‐medium small‐medium (15–19 μm diameter), and large (>24 μm diameter)cells were labeled but few, if any, large‐medium (20–24 μm diameter)cells were labeled. In ipsilateral temporal retina, soma size groups labeled included small‐medium, large‐medium, and large cells, but very few small cells. A nasal–temporal difference in the soma size of ganglion cells projecting to the SC was found: Labeled cells in temporal retina were 1.7–4.2 μm larger than their counterpats in nasal retina.Following injection of HRP into the LGNd, label was seen in contralateral nasal and ipsilateral temporal retina witn no label seen in contralateral temporal retina. The labeled cells were small‐medium, large‐medium, and large. No small ganglion cells were labeled from the LGNd. A small nasal‐temporal soma size difference in retinal ganglion cells projecting to the LGNd was seen: labeled cells in temporal retina were 1.0–2.1 μm larger than in nasal. It is concluded that all four ganglion cell size groups in the opossum project to the SC, but that only the three largest project to the LGNd.
A cobalt study of medullary sensory projections from lateral line nerves, associated cutaneous nerves, and the VIIIth nerve in adult Xenopus
Authors: Altman J. S. , Dawes E. A. 
Published: December 2004

AbstractThe medullary projections of the anterior lateral line nerve, dorsal branch (Alln.d), the posterior lateral line nerve, dorsal branch (PLLn.d), associated cutaneous nerves, and the VIIIth nerve in Xenopus laevis have been delineated by axonal infusion of cobalt chloride and silver intensification. The peripheral innervation of the posterior lateral line sense organs has also been traced. From wholemount and sectioned preparations, we describe three central projections, extending the length of the ipsilateral medulla but occupying distinct zones: lateral line afferents dorsomedially, stato‐acoustic dorsolaterally, and cutaneous ventrolaterally.Arborizations of ALLn.d and PLLn.d afferents are morphologically similar, intermingling throughout the lateral line lobe. Each divides into ascending and descending limbs bearing collaterals, which terminate in the lateral line neuropile and nucleus. Evidence is presented for directional and positional mapping in the branching of individual PLLn.d afferents and for topography in the ALLn.d projection. Second‐order neurones have been identified by transneuronal staining and their axons traced into the contralateral torus semicircularis. The morphology of efferent neurones is also described.Rostral branches of PLLn.d also contain cutaneous afferents which run through the medulla into the spinal cord, similar to the nerve V (cutaneous) projection. In nerve VIII preparations, the projection to the compact cochlear nucleus and the massive vestibular projection are identified. Cutaneous and vestibular but not lateral line afferents extend into the cerebellum.The separation of VIIIth nerve and lateral line afferents in Xenopus medulla is considered as evidence against the validity of the acousticolateralis concept. Information processing in the lateral line lobe is discussed in relation to connectivity patterns between first‐ and second‐order neurones.
Developmental relationships between trigeminal ganglia and trigeminal motoneurons in chick embryos. III. Ganglion perikarya direct motor axon growth in the periphery
Authors: Moody Sally A. , Heaton Marieta B. 
Published: December 2004

AbstractThe previous study in this series demonstrated that the ingrowth of the central axons of the trigeminal (V) ganglion is prerequisite to V motor axon outgrowth and somatic translocation. In the present experiment we determined whether further interactions with V ganglion cell bodies were required by V motoneurons after the V ganglion innervates the brainstem. Soon after the ganglion axons had penetrated the brainstem they were severed, and a barner, either permeable or impermeable, was placed between the ganglion cell bodies and the metencephalon. V motor axons grew along aberrant pathways to circumvent the impermeable barriers, many rerouting to reach the V ganglion. Only those V motor nerves which contacted the V ganglion distal to the barrier reached their target musculature in the mandible. The pattern of migration of V motoneurons was normal regardless of the V motor nerve trajectory, but the cell bodies of those axons which did not reach a muscle were not fully differentiated.When permeable barriers (Millipore filters) were implanted, the nerves followed two types of trajectories. If the pore size of the filter was small (0.45 and 0.025 μm), the V motor nerves grew identically to those observed in embryos in which impermeable barriers had been implanted. If the pore size of the filter was large (8.0 and 0.08 μm), the V motor nerve grew along its normal path directly to the barrier. Small axonal bundles from these nerves frequently grew into the filter toward the distal V ganglion.These results indicate that V motor axons preferentially grow to the V ganglion perikarya after exiting from the brainstem. Contact with the V ganglion always results in V motor nerve growth to the mandible while growth of the V motor axons to aberrant target sites only occurs when the axons fail to contact the V ganglion cells distal to the barrier.
Substance P, somatostatin, and methionine enkephalin immunoreactive elements in the spinal cord of the domestic fowl, Gallus domesticus
Authors: Lavalley A. L. , Ho R. H. 
Published: December 2004

AbstractThe occurrence and distribution of substance P (SP), somatostatin (SOM), and enkephalin (ENK) immunoreactive elements were examined in the spinal cord of the domestic fowl, Gallus domesticus. SP immunoreactive fibers and their varicosities were densest in laminae I and II, although they were also found within deeper regions of the dorsal horn. In contrast, the intermediate gray area, the area around the central canal, and the ventral horn, contained fewer SP immunoreactive fibers. The distribution of ENK immunoreactivity in the gray matter was similar to that described for SP although immunoreactive fibers were denser around the central canal and in the intermediate zone. Few SOM immunoreactive fibers were present in the dorsal horn the area around the central canal, and the ventral horn. All three peptidergic immunoreactive elements were found in and around the nucleus of Terni, an autonomic area. Throughout the lumbosacral enlargement SP, SOM, and ENK immunoreactive varicosities were found adjacent to the lumbosacral sinus and in fibers traversing the glycogen body. In addition, at caudal lumbar and rostral sacral levels a plexus of SP and SOM immunoreactive fibers was observed to be in close relationship with presumed motoneurons.