bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendroaxonic synapses in the substantia gelatinosa glomeruli of the spinal trigeminal nucleus of the cat
Authors: Gobel Stephen 
Published: January 2005

AbstractThe glomeruli in the substantia gelatinosa layer of the spinal trigeminal nucleus of the cat contain three kinds of dendritic processes. One of these, the type 2 dendrite, contains large synaptic vesicles in its spine heads and in its shaft. The type 2 dendrite receives axodendritic synapses from primary trigeminal afferent (C) axons and an occasional axodendritic synapse from small axonal (P) endings with small synaptic vesicles. The type 2 dendrites in turn form dendroaxonic synapses on the C endings. The dendroaxonic synapse and the axodendritic synapse of the C ending typically occur in reciprocal pairs. The axodendritic synapse usually lies in the depths of scalloped depressions in the surface of the C ending while the dendroaxonic synapse is found on the rim of the depression. Type 1 spines, i.e., dendritic spines receiving axodendritic synapses from the primary ending and lacking synaptic vesicles, also receive dendrodendritic synapses from type 2 dendrites.The types 2 dendrite with its large, rounded synaptic vesicles is considered to be excitatory at its dendroaxonic and dendrodendritic synapses. The type 2 dendrites course from glomerulus to glomerulus receiving their excitatory input through the axodendritic synapses of C axons. A type 2 dendrite, in response to C axon excitation would activate type 1 spines directly through their dendrodendritic synapses (C→2→1) and indirectly by increasing transmitter release at the axodendritic synapses of the C axonal endings through their dendroaxonic synapses (2→C→1). The type 2 dendrites could serve two functions. First, they may prolong transmitter release from the axodendritic synapses of C axonal endings beyond the time of arrival of incoming action potentials because of the reciprocal pairing of dendroaxonic and axodendritic synapses (C⇋2). Second, they may extend the spatial range of the excitatory output of active primary afferent axons to type 1 spines of glomeruli whose primary afferent axons may be inactive (C→2→1).
The retina and retinal projection on the lamina ganglionaris of the crayfish Pacifastacus leniusculus (Dana)
Authors: Nassel D. R. 
Published: January 2005

AbstractThe retinular cell morphology and ommatidia arrangement in the crayfish retina are studied, Each ommatidium contains eight receptor cells (R1–R8). Seven of the them (R1–R7) contribute to a large spindle‐shaped rhabdom with orthogonal layers of microvilli.Distal to the rhabdom of R1–R7, the 8th receptor cell forms a separate rhabdom with horizontal microvilli. The cell is four‐lobed, is devoid of screening pigments, and forms a thin axon projecting past the first optic neuropile (lamina ganglionaris) and has a terminal in the second (medulla externa), indicating a separate function of the receptor.The axons from the eight receptors of one ommatidium project to different synaptic compartments (cartridges) in the lamina. A pattern is described where eight axons from three adjacent ommatidia join in one cartridge; and conversely, the axons from one ommatidium split and join to three cartridges.The seven axons from R1–R7 terminate in two levels of the lamina plexiform layer (epl 1 and epl 2), four in the distal and three in the proximal part. Among the monopolar ganglion cells, two types are found with lateral branches restricted to either of the two receptor terminal layers (M3 in epl 1 and M4 in epl 2) and axons terminating in the second optic neuropile. A correlation between the two orthogonal channels for e‐vector discrimination and the two levels of terminals within the lamina is suggested.The retina is divided into a dorsal and a ventral part with a mirror symmetry axis horizontally in the eye.
Reconstruction of neurons of dorsal horn proper using golgi‐stained serial sections
Authors: Mannen Hajime , Sugiura Yasuo 
Published: January 2005

AbstractThree neurons located in the dorsal horn (Lamina III) have been reconstructed using Golgi‐stained serial sections. These cells including dendritic and axonal branchings appear to remain within the dorsal horn and to belong to small‐sized local interneurons of the dorsal horn proper.The measurements have been made with various criteria: the medio‐lateral, dorso‐ventral and rostro‐caudal extents of the dendritic tree as well as the axonal branchings, total dendritic and axonal length, number of axonal endings and distance from the starting point of the axon at the dendrite to the point where the dendrite joins the soma (S‐A distance).
The cat optic nerve: Fibre total count and diameter spectrum
Authors: Hughes A. , Wässle H. 
Published: January 2005

AbstractAn electron microscopic examination of two cat optic nerves indicates a mean total count of 193,000 fibres ranging from 0.5μ to 13.5μin diameter. This count, although nearly double any previously reported, supports recent minimum estimates of the retinal ganglion cell population of the cat eye. A radial gradient of packing density exists across the nerve close to the globe; a high density “core” with a unimodal fibre diameter spectrum may be identified as the area centralis outflow and a peripheral low density region with a trimodal diameter spectrum contains the projection of the peripheral retina. Division of the peripheral fibre spectrum suggests the percentages of α,βandγ ganglion cells in the peripheral retina to be 5%, 42% and 53% respectively.
The structural maturation of the stato‐acoustic nerve in the cat
Authors: Romand Raymond , Sans Alain , Romand Marie Rose , Marty Robert 
Published: January 2005

AbstractThe maturation of the stato‐acoustic nerve in the cat was studied by light and electron microscopy from the fetal stage to the adult. Measurement of the outer diameter of the fibers and the study of the myelination process revealed that myelination begins earlier for the vestibular nerve than for the cochlear nerve: by the fifty‐third day of gestation 64% of the vestibular fibers have already passed the promyelin stage whereas for the cochlear nerve this promyelin stage begins for the majority of fibers on the fifty‐seventh gestation day. Afterward, maturation proceeds more rapidly for the cochlear nerve. In the case of both nerves, maturation is still incomplete at two months of age.Concerning the relationship between the thickness of the myelin sheath and the axoplasmic diameter, there is already a good correlation by the fifty‐seventh day of gestation in the vestibular nerve, whereas it appears several days after birth in the cochlear nerve.
Complementary laminar terminations of afferents to area 17 originating in area 18 and in the lateral geniculate nucleus in squirrel monkey
Authors: Tigges Johannes , Tigges Margarete , Perachio Adrian A. 
Published: January 2005

AbstractThe projections from area 18 and the lateral geniculate nucleus onto area 17 of the squirrel monkey (Saimiri) were investigated with retrograde (horseradish peroxidase) and anterograde (tritiated proline) labelling techniques, and the (Fink‐Heimer) silver impregnation method for degenerating axons and their terminals.The association fibers from area 18 terminated in all layers of area 17 except in layer IV and in the lower aspect of layer IIIc. The greatest number of terminals were in layers I, V and VI. The bulk of geniculocortical fibers terminated in layer IV and the lower aspect of layer IIIc; a minority of the geniculocortical fibers terminated in layer VI and the lower aspect of layer IIIb. Thus, the majority of fibers from the two sources investigated terminate in a complementary laminar fashion in area 17.The portion of area 17 on the lateral surface of the hemisphere, where the central visual field is represented, received a less dense projection from the geniculate nucleus than the striate cortex in the calcarine fissure, where the peripheral visual field is represented. Ocular dominance columns were not apparent in the striate cortex. No evidence was found that the lateral geniculate nucleus projects to area 18.The results of combined injections of horseradish peroxidase and tritiated proline in area 17 indicated a point‐to‐point reciprocity between area 17 and the ipsilateral lateral geniculate nucleus.
Observations on labeling of neuronal cell bodies, axons, and terminals after injection of horseradish peroxidase into rat brain
Authors: Hedreen John C. , McGrath Susan 
Published: January 2005

AbstractWe observed with light microscopy the evolution of neuronal labeling phenomena in rats with two hours to eight days survival following injection of horseradish peroxidase (HRP) into the neostriatum. We compared the results of neostriatal injection with those injection of the overlying neocortex. The following conclusions were reached.The zone of diffuse background HRP around the injection site began to shrink after 18 hours. The extent of the early zone of diffusion was marked from 18 hours to two days by a universal granular labeling of neurons. This granular cell labeling appears to be the result of earlier diffuse cell labeling rather than retrograde axonal transport.Retrograde labeling of cells takes place from terminals and from damaged axons. Anterograde labeling of what appear to be terminals and fine preterminal axons takes place only from cells in the injection area, and not from either intact or damaged axons of passage. Usually the axons engaged in such retrograde or anterograde transport are not visibly labeled. Labeling of cells and terminals is generally optimal at 12 to 24 hours, but corticostriatal cells in layer V of the neocortex are seen best at 24 to 36 hours. The area from which retrograde labeling of cells takes place is larger than that from which anterograde labeling of terminals occurs.Massive intra‐axonal movement of HRP away from the injection site occurs within a few hours in axons of passage as well as those originating there. This axonal labeling fades in most axons by 24 hours, but certain axons remain darkly labeled. The latter are probably damaged, since labeled axons which appear to be degenerating are later (3–5 days) seen in the same place, and Fink‐Heimer staining of adjacent sections also shows degenerating axons in these regions. The early massive labeling of axons can lead to short‐lived labeling of complete axonal arborizations within the range of this intra‐axonal movement of HRP. But it seems to have no relation to the longer‐lived labeling of distant cells and terminals, which presumably results from active axonal transport. This suggests that HRP entering axons of passage is not captured by the axonal transport mechanisms.
An autoradiographic study of the descending connections of the mammillary nuclei of the rat
Authors: Cruce Judith A. F. 
Published: January 2005

AbstractThe descending connections of the mammillary nuclei of the rat were studied using the autoradiographic technique to trace anterograde axonal connections. Injections of tritiated leucine or tritiated proline were stereotaxically aimed at either the medial or lateral mammillary nucleus. Label in the medial and lateral mammillary nuclei was rated as either high or low. With a rating of high in both medial and lateral mammillary nuclei (11 animals) three major projection sites were seen: the dorsal tegmental nucleus (DTN), the ventral tegmental nucleus (VTN) and a pontine region which included both the pontine grey and the tegmental reticular nucleus. In the nine animals in which the medial mammillary nucleus was rated high but the lateral mammillary nucleus was rated low, no label was present in DTN, although the other two regions were labeled. The one animal in which the lateral mammillary nucleus was high but the medial was low, had label in all three major projection sites; since fibers destined for the DTN pass through the VTN, it could not be determined whether or not lateral mammillary efferents were in synaptic contact with the VTN. Labeled fibers were present throughout a wide dorsal‐ventral extent of the mesencephalon; these fibers are components of the mammillotegmental system and not part of the mammillary peduncle.
Early development of amacrine cells in the mouse retina: An electron microscopic, serial section analysis
Authors: Hinds James W. , Hinds Patricia L. 
Published: January 2005

AbstractThe development of retinal amacrine cells in mice at the fifteenth day of gestation (E‐15) has been analyzed by reconstructing large numbers of cells from serial thin sections. This information has been supplemented by reconstructing cells from E13 and E17 retinas as well as autoradiographic studies of time of origin of cells arising in the period before E15. The presence of bipolar amacrine cells in the outer ventricular layer, first suggested by Cajal, has been confirmed by reconstructing cells from the E17 retina when a clearly defined inner plexiform layer (IPL) is first found. The less mature bipolar amacrine cells present at E17 resemble similar cells found in the E15 retina; they are distinguished from the pre‐axonic, migratory stage of ganglion cells by their flattened rather than cylindrical processes, the darker cytoplasm of these processes, and the position of their centrioles closer to the nucleus. Examination of large numbers of reconstructed cells throughout the thickness of the E15 retina has revealed no forms directly transitional from ventricualr cells to bipolar amacrine cells; insted, bipolar amacrine cells appear to be derived by retrograde (sclerally directed) migration of cells in the ganglion cell layer that resemble normal ganglion cells but lack axons. The origin of these anaxonic cells of the ganglion cell layer is not certain but several findings, including evidence of degenerating axons in the optic nerve, sugest that they are derived by loss of the primitive axons of ganglion cells. Thus amacrine cells may be formed by a relatively late differentiating event that occurs after migration of cells to the ganglion cell layer. Such a developmental origin would offer a plausible explanation for the displaced amacrine cells in the ganglion cell layer and IPL described in the adult, as well as perhaps the close similarity of the dendritic trees of certain subtypes of normal, nondisplaced, ganglion and amacrine cells.
A cytologic study of grandry corpuscle development in chicken toe skin
Authors: Idé Chizuka , Munger Bryce L. 
Published: January 2005

AbstractThe developmental sequence of Grandry corpuscles was traced in the toe skin of embryonic, young and adult chickens by light and electron microscopy. The developing Grandry cells as well as Schwann cells can first be identified at stage 38(˜ 12 days of incubation) due to the cytoplasmic content of scattered secretory granules of ˜ 100 nm in diameter. Such developing Grandry cells are always associated with nerve fibers. During late stages (stages 40–42, 14–16 days of incubation) several immature Grandry cells formed cell clusters in the dermis. Such cell clusters were always in contact with growing nerve tips or Schwann cells. Immature Grandry cells were separated from one another and dispersed in the connective tissue compartment at stages 44–45 (near hatching). By the time of hatching the developing Grandry cells began to have the morphological characteristics of adult cells. They were relatively large in cell diameter (˜ 10 μm) containing numerous secretory granules and bundles of filamentous material. These cells had finger‐like cytoplasmic processes. The Grandry cells at this time had an intimate relationship with nerve fibers and satellite cells. The fact that Grandry cells were always associated with nerve fibers throughout deveopment would support the hypothesis that Grandry cells are derived from neural elements, perhaps neural crest. Satellite cells of Grandry corpuscles are apparently derived from Schwann cells. Grandry cells and corpuscles are adult in form by two to three months of age.
An autoradiographic study of midbrain‐diencephalic projections to the inferior olivary nucleus in the opossum (Didelphis virginiana)
Authors: Linauts M. , Martin G. F. 
Published: January 2005

AbstractTechniques of intra‐axonal transport were utilized to elucidate the organization of diencephalic and midbrain projections to the inferior olivary nucleus of the Virginia opossum. Retrograde transport of horseradish peroxidase injected into olive suggests that terminals within it arise from the subparafascicular nucleus of the caudal thalamus, the nucleus of Darkschewitsch, the fields of Forel, the interstitial nucleus of Cajal, the periaqueductal grey, the caudla pretectal nucleus, the tegmentum dorsomedial to the red nucleus, the red nucleus (minimal), the nucleus linearis, as well as the dorsolateral midbrain tegmentum and tectum (Henkel et al., '75).Tritiated leucine injections were made into each of the above‐mentioned cell groups so that the olivary terminals of their axons could be demonstrated autoradiographically. In general, the projection systems show three basic patterns of organization. Ventormedial areas of the midbrain, including the ventral periaqueductal grey, the interstitial nucleus of Cajal, part of the red nucleus and the tegmentum dorso‐medial to it, provide a substantial and topographically organized projection to the principal nucleus of the olive, as well as minor inputs to the accessory neclei. Secondly, neurons within the subparafascicular nucleus, the nucleus of Darkschewitsch and the fields of Forel project most heavily to parts of the medial accessory nucleus, although they also provide input to the other major subdivisions of the olive. Third, axons from the dorsolateral tegmentum and tectum completely avoid the principal nucleus, while supplying small regions of the accessory nuclei.
The vestibular nuclei in the domstic hen (Gallus domesticus). III. Ascending projections to the mesencephalic eye motor nuclei
Authors: Wold Jan Egil 
Published: January 2005

AbstractFollowing injections of horseradish peroxidase in the oculomotor and the trochlear nuclei in the hen, the occurrence of labeled cells was plotted in the vestibular nuclei. The majority of labeled cells was localized in the superior, the medial, and the tangential nucleus. Within the superior nucleus the cells were found mainly caudally, extending medially and ventrally in central areas. In the medial nucleus labeled cells were localized exclusively in its rostral half, mainly in ventrolanteral regions. Most, if not all, cells in the nucleus tangentialis project rostrally. In addition, rostrally projecting vestibular cells were found in the cell group A and the rosrolateral part of the descending nucleus. The projection to the oculomotor nuclear complex is from the superior nucleus and the cell group A bilateral but chiefly ipsilateral, from the medial nucleus bilateral, from, the tangential nucleus and the rostral pole of the descending nucleus chiefly contralateral. Massive labeling was found in the abducens nucleus, somewhat less in the reticular formation, mainly in lateral regions of the medial part at the level of the abducens and facial nuclei. Labeled cells were, in addition, found in the deep layers of the optic tectum, and scattered cells in the nucleus raphe. The findings are discussed in the light of what is known of the organization of the vestibular nuclei in the hen and the rostral projection of the vestibular nuclei in mammals.
Radioautographic investigation of gliogenesis in the corpus callosum of young Rats I. Sequential changes in oligodendrocytes
Authors: Imamoto Kikuko , Paterson Jean A. , Leblond C. P. 
Published: January 2005

AbstractThe corpus callosum of young rats was examined to clarify the behavior of the three subtypes of oligodendrocytes (the large organelle‐rich “light oligodendrocytes,” the smaller and more densely stained cells referred to as “medium oligodendrocytes,” and the even smaller and denser “dark oligodendrocytes”). It was hoped to find out whether cells of the three subtypes undergo division and how they are related to one another. 3H‐thymidine was given intraperitoneally as single or three shortly spaced injections to a first group of 19‐ to 20‐day old rats weighing about 40 g, and to a second group of 25‐day old rats weighing about 80 g. The animals were sacrificed at various time intervals from 2 hours to 35 days after 3H‐thymidine administration. Pieces of corpus callosum were taken near the superior lateral angle of the lateral ventricles; and semithin sections were radioautographed and stained with toluidine blue.Two hours after 3H‐thymidine injection, label is virtually absent from light, medium and dark oligodendrocytes, from microglia, and probably from astrocytes, but is present in about 10% of the immature glial cells, which include the poorly differentiated glioblasts and the partially differentiated oligodendroblasts and astroblasts. Hence, the cells undergoing DNA synthesis and mitosis in the corpus callosum are these three types of immature cells.During the week that follows the administration of 3H‐thymidine, label appears in oligodendrocytes and astrocytes, which presumably have arisen from the initially labeled immature cells. The oligodendrocytes acquire label in a sequential manner: the light cells show label first and their labeling index reaches a peak at the seven‐day interval; the medium oligodendrocytes become labeled next with a labeling peak toward the 14‐ and 21‐day intervals and, finally, the dark oligodendrocytes with a peak around the 28‐day interval. Analysis by the method of Zilversmit et al. (1942‐1943) provides precise details on the sequence: immature cells presumed to be oligodendroblasts give rise to light oligodendrocytes which, after four to seven days, transform into medium oligodendrocytes which, after another 11 to 18 days, transform into dark oligodendrocytes. The dark cells may persist indefinitely or turn over at a very slow rate.It is concluded that oligodendrocytes arise from the last division of oligodendroblasts and develop in three main periods; a light stage lasting less than a week, a medium stage lasting about two week, and a very long lasting dark stage.