bluuebunny/crossref_metadata_2025_split huggingface dataset:
The hippocampal mossy fiber system of the rat studied with retrograde tracing techniques. Correlation between topographic organization and neurogenetic gradients
Authors: Gaarskjaer Frank B. 
Published: May 2005

AbstractThe topographical organization of the hippocampal mossy fiber system, which connects the dentate granule cells with the pyramidal cells of the regio inferior, has been examined in rats with retrograde tracing methods. Following the application of the fluorescent dye True Blue to different parts of the mossy fiber layer in the hippocampal regio inferior, retrogradely labeled granule cells were observed in the dentate fascia. The distribution of the labeled cells within the dentate granule cell layer indicates that all mossy fibers have an almost parallel, slightly descending course in regio inferior near the dentate hilus. In the ventricular part of regio inferior, particularly toward the transition to the regio superior, the mossy fibers are sorted out according to the position of their parent cell bodies within the granular layer. Near the transition to regio superior the fibers from lateral granule cells extend both septally and temporally over a longer distance than the fibers from more medial cells. Similarly, the fibers coming from the superficial cells extend both septally and temporally over a longer distance than those from the deep cells. The mossy fibers arising from a specific septotemporal level of the dentate fascia innervate a segment of the regio inferior that extends approximately 180 μm above to approximately 1,600 μm below the level of origin. Similar results were obtained following injections of Nuclear Yellow and horseradish peroxidase.Since previous studies have demonstrated that the granule cells are formed along gradients from lateral to medial and from superficial to deep, there appears to be a correlation between the formation, and hence the position, of the granule cells and the topography of their projection into the regio inferior.
Experimental studies on cerebellar foliation. I. A qualitative morphological analysis of cerebellar fissuration defects after neonatal treatment with 6‐OHDA in the rat
Authors: Sievers J. , Mangold U. , Berry M. , Allen C. , Schlossberger H. G. 
Published: May 2005

AbstractThe present report describes the natural history of defective cerebellar fissuration in the rat after neonatal treatment with 6‐hydroxydopamine (6‐OHDA). Within 24 hours after an intracisternal (IC) injection of 100 μg 6‐OHDA cerebellar pial fibroblasts degenerated almost completely and were phagocytosed by macrophages within 2–5 days postinjection (dpi) leaving the cerebellar surface denuded of pia. Bergmann glia end feet at first exhibited morphological signs of gliosis and later formed new sprouts that penetrated the basal lamina and grew into the subarachnoid space covering regenerating pial fibroblasts and also invading ectopic colonies of external granular layer (EGL) cells. Breaches in the basal lamina appeared after the pial fibroblasts had been destroyed and were confined to areas where Bergmann glia end feet were absent and where EGL cells were opposed to the basal lamina. EGL cells escaped through these fractures into the subarachnoid space in the fissures, where they proliferated to form large colonies of granule and stellate cells. In those fissures in which EGL ectopia featured, opposing folia fused and fissures were lost. These findings suggest that pial fibroblasts and the basal lamina have an important role in maintaining lobular partition during development of the cerebellum, in establishing cerebellar fissures, and in consolidating Bergmann glia‐EGL cell relationships as a prerequisite for orderly migration of EGL cells.
Experimental studies on cerebellar foliation. II. A morphometric analysis of cerebellar fissuration defects and growth retardation after neonatal treatment with 6‐OHDA in the rat
Authors: Allen C. , Sievers J. , Berry M. , Jenner S. 
Published: May 2005

AbstractQuantitative analyses were undertaken of the gross morphological changes in cerebellar foliation and fissuration patterns in the rat induced by neonatal treatment with 6‐hydroxydopamine (6‐OHDA). After an intracisternal (IC) injection of 100 μg 6‐OHDA, cerebella were much smaller than those of controls and progressively developed abnormal fissures with age, characterized by a loss of pial coverings and fusion of adjacent external granular layers (EGL). Such deformities were most severe anteriorly with relative sparing of posterior fissures. It was also found that the growth rate of individual folia was reduced differentially with a clear linear relationship between the magnitude of the reduction of folial growth rates and the extent to which adjacent fissures were spared. This relationship implied that the basal lamina fractured when the rate of expansion of folia outstripped the rate of deposition of the lamina.The adverse effects of 6‐OHDA on pial fibroblasts were reduced by concomitant IC injection of 10 μg bovine serum albumin (BSA) which allowed fissures to develop normally although most other cerebellar growth defects were unaltered. These findings thus demonstrated the importance of the pia mater for the establishment of fissures.Folia were diminutive after 6‐OHDA treatment but otherwise surprisingly normal even in areas where pia‐lined fissures were absent. This finding suggests that although foliation and fissuration may be complementary morphogenic entities, the former is the primary event resulting from buckling forces generated by proliferation of EGL cells during ontogeny. Basal lamina investment is dependent on glia limitans/pia mater interaction, which normally keeps pace with folial expansion.
The intercollicular pathway in the golden hamster: An anatomical study
Authors: Fish Stephen E. , Goodman Dianne K. , Kuo David C. , Polcer Jeffrey D. , Rhoades Robert W. 
Published: May 2005

AbstractThe intercollicular pathway of the hamster was studied by means of a combination of horseradish peroxidase (HRP), autoradiographic, and double‐labeling (nuclear yellow‐HRP) techniques. Small deposits of HRP marked significant numbers of cells in the contralateral colliculus only when the injection site included the laminae ventral to the stratum opticum. Anterior deposits labeled many more neurons than injections into the caudal part of the tectum. Of the cells labeled by our injections, 18.2% were located in the superficial collicular laminae (stratum griseum superficiale and stratum opticum), and the remainder (81.8%) were in the deep layers. A wide variety of morphological cell types contributed axons to the intercollicular projection, and in a given animal the loci of the labeled neurons were generally symmetrical with the injection site.Small deposits of [3H]‐leucine resulted in contralateral labeling only when the injection included the deep collicular laminae. The transported label was most dense in the stratum griseum intermediale and stratum griseum profundum, and its location was generally homotopic with the injection site.Experiments in which collicular HRP deposits were combined with large cervical spinal or pontine reticular injections of Nuclear Yellow indicated that intertectal neurons did not, in most cases, contribute axon branches to the spinal or pontine reticular projections of the colliculus.Receptive field data obtained at the time of the HRP and/or [3H]‐leucine deposits demonstrated that the collicular representations of the ipsilateral and at least 45° of the contralateral hemifields were encompassed by intercollicular connections. This was also true for the somatosensory representation of the entire head and a portion of the neck.
Locust local nonspiking interneurons which tonically drive antagonistic motor neurons: Physiology, morphology, and ultrastructure
Authors: Wilson John A. , Phillips Christine E. 
Published: May 2005

AbstractLocal nonspiking interneurons have been implicated in the control of behavior. We have characterized the physiology of two local nonspiking interneurons in the locust and subsequently examined the neurons in the light and electron microscopes. Physiologically the two interneurons have opposite effects upon antagonistic motor neurons and are tonically releasing transmitter at their “resting potentials.” This combination of tonic release and reciprocal driving of antagonistic motor neurons by single interneurons provides a hitherto undescribed means of controlling posture. One interneuron (DCVII, 4) excites flexor tibiae and inhibits the slow extensor tibiae motor neurons when depolarized. The other interneuron (DCVII, 5) inhibits the flexor tibiae and excites the slow extensor tibiae motor neurons when depolarized. In both cases, when the interneurons are hyperpolarized, they have the opposite effects upon the same motor neurons. Intracellular staining of these neurons confirms that they are local interneurons. Furthermore, an examination of sectioned material shows that the neurons are unique and can be identified as such in a population of locust neurons. Ultrastructurally, we find synapses only on the smaller (less than 2 μm) branches. These neurons may form the presynaptic element in either of two configurations, these being the discrete density (one presynaptic, one postsynaptic) and the dense bar (one presynaptic, two postsynaptic) type of configurations. The functional implications of these findings for neurons controlling posture are discussed.
Retinal W‐cell projections to the medial interlaminar nucleus in the cat: Implications for ganglion cell classification
Authors: Rowe Michael H. , Dreher Bogdan 
Published: May 2005

AbstractThe perikaryal sizes and retinal distribution of ganglion cells labeled after small iontophoretic injections of horseradish peroxidase (HRP) into the medial interlaminar nucleus (MIN) were studied. Injections were also made into the LGNv and the C‐laminae of the dorsal lateral geniculate nucleus (LGNd) for comparison. The results are consistent with suggestions that the MIN contains three approximately vertically oriented laminae which, from medial to lateral, receive their retinal input from, respectively, contralateral nasal, ipsilateral temporal, and contralateral temporal retina.Each MIN lamina receives afferents from two distinct groups of retinal ganglion cells: (1) cells with large somas (over 25 μm), coarse primary dendrites, large dendritic trees (500–900 μm in diameter), and coarse axons; (2) cells with medium‐sized somas (14–20 μm), medium‐caliber primary dendrites, large dendritic trees (350–700 μm), and fine axons. The large cells are clearly Y‐cells or alpha cells, and they provide approximately 50% of the retinal input to all layers of the MIN. The medium‐sized cells, which provide the remaining 50% of the retinal input to the MIN, are, we argue, W‐cells, since they do not differ in soma size, dendritic morphology, axon caliber, or receptive field properties from medium‐sized W‐cells which project to other thalamic or midbrain structures. These results suggest two phylogenetic trends within the W‐cell group: (1) the differentiation of thalamic and midbrain components; and (2) the further differentiation of ipsilateral and contralateral projections within the midbrain component. This latter division corresponds to the distinction between W1 and W2 cells described previously (Rowe and Stone, '77, '80).
Afferent projections to the deep mesencephalic nucleus in the rat
Authors: Veazey Randolph B. , Severin Charles M. 
Published: May 2005

AbstractAfferent projections to the deep mesencephalic nucleus (DMN) of the rat were demonstrated with axonal transport techniques. Potential sources for projections to the DMN were first identified by injecting the nucleus with HRP and examining the cervical spinal cord, brain stem, and cortex for retrogradely labeled neurons. Areas consistently labeled were then injected with a tritiated radioisotope, the tissue processed for autoradiography, and the DMN examined for anterograde labeling. Afferent projections to the medial and/or lateral parts of the DMN were found to originate from a number of spinal, bulbar, and cortical centers.Rostral brain centers projecting to both medial and lateral parts of the DMN include the ipsilateral motor and somatosensory cortex, the entopeduncular nucleus, and zona incerta. At the level of the midbrain, the ipsilateral substantia nigra and contralateral DMN likewise project to the DMN. Furthermore, the ipsilateral superior colliculus projects to the DMN, involving mainly the lateral part of the nucleus.Afferents from caudal centers include bilateral projections from the sensory nuclei of the trigeminal complex and the nucleus medulla oblongata centralis, as well as from the contralateral dentate nucleus. The projections from the trigeminal complex and nucleus medullae oblongatae centralis terminate in the intermediate and medial parts of the DMN, whereas projections from the contralateral dentate nucleus terminate mainly in its lateral part.In general, the afferent connections of the DMN arise from diverse areas of the brain. Although most of these projections distribute throughout the entire extent of the DMN, some of them project mainly to either medial or lateral parts of the nucleus, thus suggesting that the organization of the DMN is comparable, at least in part, to that of the reticular formation of the pons and medulla, a region in which hodological differences between medial and lateral subdivisions are known to exist.
Three‐dimensional structure of the mammalian suprachiasmatic nuclei: A comparative study of five species
Authors: Lydic Ralph , Albers H. Elliott , Tepper Beverly , Moore‐Ede Martin C. 
Published: May 2005

AbstractThe suprachiasmatic nuclei from five mammalian species (rat, hamster, cat, rhesus, and squirrel monkey) were reconstructed in three‐dimensions by use of computer graphics and conventional histological techniques. The gross nuclear structures of the suprachiasmatic nuclei have complex threedimensional geometries in every plane of orientation, and between the five species there are marked differences in the three‐dimensional morphology of the suprachiasmatic nuclei. These dimensionally accurate reconstructions are discussed in relation to previous data suggesting morphological and/or functional specialization within specific regions of the suprachiasmatic nuclei.
Cell death in the mammalian visual system during normal development: II. Superior colliculus
Authors: Finlay B. L. , Berg A. T. , Sengelaub D. R. 
Published: May 2005

AbstractDegenerating cells may be observed with light microscopy in the hamster superior colliculus during early postnatal development. In the superficial gray layer and stratum opticum, 1.8 degenerating cells for each 1,000 live cells could be seen on the first postnatal day. This rate increased to 5.6 degenerating cells per 1,000 live cells by postnatal day 5, and declined to 2.6 per 1,000 live cells by postnatal day 8. The rate of cell degeneration was consistently elevated at the medial, lateral, and caudal margins of the superficial gray layer relative to the center. In the intermediate and deep gray layers, the rate of cell death was consistently higher, starting at three degenerating cells per 1,000 on the first postnatal day, increasing to 15 per 1,000 on postnatal day 5, and declining to 4.7 per 1,000 by postnatal day 8. In contrast to the superficial gray layer, the number of degenerating cells in the central versus peripheral segments of the intermediate and deep gray layers was quite similar.Although the rate of observable degeneration is low, the likely rapid clearance of degenerating cell debris indicates a substantial loss of cells from the midbrain tectum in early development. The time course of observable degeneration, the amount, and the distribution of degenerating cells are quite similar in the tectum, and its major innervating structure, the retina.
The localization of vasotocin and neurophysin neurons in the diencephalon of the pigeon, Columba livia
Authors: Berk Mitchell L. , Reaves Troy A. , Hayward James N. , Finkelstein Judith A. 
Published: May 2005

AbstractVasotocin (VT)‐ and neurophysin (NP)‐synthesizing neurons were demonstrated by immunocytochemistry in the diencephalon of the pigeon, Columba livia. Three diencephalic regions contain VT‐NP cells: (1) periventricular preoptic area and hypothalamus, including nucleus periventricularis magnocellularis (PVM); (2) lateral preoptic area and hypothalamus; and (3) dorsal diencephalon. The immunoreactive cells in each of these three regions were divided into groups based on cytology and topography. No differences were found in the location of VT and NP cell groups.The periventricular region contains three continuous cell groups (P1–P3) extending from the posteroventral preoptic area to the anterodorsal hypothalamus and PVM. The lateral region has two cell groups composed of medium‐ to large‐sized cells associated with the quintofrontal tract (L1) or with the optic tract (L2), while a third group (L3) lies between these two cell groups. Two accessory cell groups reside in the dorsolateral hypothalamus; L4 contains scattered cells of varied size, whereas L5 has small‐ to medium‐sized cells clumped together. The dorsal diencephalic cell groups are found in the following locations: (1) lateral and dorsal to the lateral forebrain bundle (DD1); (2) in the area ventral to the dorsomedial anterior thalamic nucleus and dorsolateral to PVM (DD2); and (3) at the dorsolateral border of nucleus rotundus (DD3).To avoid potentially inaccurate mammalian homologies, the cell group nomenclature denotes topographic position. Nevertheless, the presence of VT‐NP cells in PVM and projections to the brainstem and spinal cord suggest a homology between PVM and some of the parvocellular subnuclei of the mammalian paraventricular nucleus.
Overall distribution of substance P‐containing nerves in the wall of the cerebral arteries of the guinea pig and its origins
Authors: Yamamoto Kazumi , Matsuyama Tomohiro , Shiosaka Sadao , Inagaki Shinobu , Senba Emiko , Shimizu Yoshiki , Ishimoto Ichiro , Hayakawa Tōru , Matsumoto Masayasu , Tohyama Masaya 
Published: May 2005

AbstractThe overall distribution of substance P‐like immunoreactivity (SPI) in the wall of the cerebral arteries and their origins were investigated in the guinea pig by using whole‐mounts.Two types of SPI fibers were seen: one forming dense fiber bands and lo‐cated among the periadventitial nerves, and the other forming a meshwork. The SPI fibers located in the periadventitial nerves often leave these nerves to form a meshwork of SPI fibers of varying density according to the diame‐ter or location of the blood vessels.The present study suggests that: (1) SPI fibers located on the circle of Willis and its branches originate from SPI cells in the trigeminal ganglion; (2) SPI fiber's of the rostral one‐third of the basilar artery originate partly from trigeminal SPI cells; and (3) SPI fibers in the caudal two‐thirds of the basilar artery originate exclusively from other SPI cells, apart from the tri‐geminal ganglion.
The indusium griseum and anterior hippocampal continuation in the rat
Authors: Wyss J. M. , Sripanidkulchai K. 
Published: May 2005

AbstractThe morphology and connections of the indusium griseum (IG) and anterior hippocampal continuation (AHC) suggest that this cortex contains analogues to several portions of the hippocampal formation. Whereas the outer neuronal layer of this cortex is made up of cells which are similar in structure to the neurons of the granule cell layer of the dentate gyrus, the three successively deeper layers contain morphological analogues to the neurons of the dentate hilus, Ammon's horn, and the subiculum, respectively. The neurons within each of these four layers of the AHC and IG have afferent and efferent connections which are quite similar to the connections of their hippocampal counterparts. Thus, the granule cells of the IG and AHC receive laminar inputs from the entorhinal cortex, the IG‐AHC itself, and the supramammillary region. Each of these three classes of inputs ends at successively more proximal positions on the dendritic tree of these granule cells. Other inputs to this region include those from the septal nuclei and the olfactory bulb. The deeper layers of the IG and AHC receive several inputs, including those from the thalamic and septal nuclei and the entorhinal cortex. The efferent cell bodies of the IG and AHC are segregated in such a way that the granule cells appear to give rise to only short connections, while the hilar cells project to the granule cells, the intermediate pyramidal neurons project to other portions of the IG and AHC and to the olfactory bulb, and the deep pyramidal neurons project to the diencephalon. These results demonstrate that the IG‐AHC is a continuation of the hippocampal formation.
Organization of the projections of a circumventricular organ: The area postrema in the rat
Authors: van der Kooy Derek , Koda Leonard Y. 
Published: May 2005

AbstractThe projections of the rat area postrema were analysed using antero‐grade and retrograde axonal transport techniques. Discrete injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP) into the area postrema produced anterograde labeling in specific medullary and pontine nuclei. In the medulla, anterograde labeling was present in the internal solitary zone and dorsal division of the medial solitary nucleus, both of which also contained a small number of retrogradely labeled perikarya. Prominent projections to the dorsal motor nucleus of the vagus were seen only if the WGA‐HRP injections in the area postrema invaded dorsal solitary nuclei. In the pons, anterograde labeling was present in the parabrachial nuclei, the dorsolateral Legmen tal nucleus, and the pericentral division of the dorsal tegmental nucleus. By far the major pontine projection was to the dorsolateral region of the middle one‐third of the rostrocaudal extent of the parabrachial nuclei. Retrograde fluorescent tracing studies indicated that most area postrema neurons take part in this parabrachial projection. The area postrema projection to the parabrachial nuclei was bilaterally distributed, whereas that from the dorsal solitary nuclei was primarily ipsi‐lateral. The external solitary zone, immediately subadjacent to the area postrema, neither received area postrema projections nor participated in the projections to the parabrachial nuclei. Fluorescent retrograde double labeling studies confirmed the bilateral nature of the area postrema projection to the parabrachial nuclei. In addition, because no doubly labeled neurons were observed it appears that individual area postrema neurons project to either side but not both sides of the dorsal pons. Thus, numerous neuronal pathways exist for the transfer of blood‐borne information (that cannot cross the blood‐brain barrier) from the area postrema to other brain regions.