bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the brain stem in the rat. III. Thymidine‐radiographic study of the time of origin of neurons of the vestibular and auditory nuclei of the upper medulla
Authors: Altman Joseph , Bayer Shirley A. 
Published: January 2005

AbstractGroups of pregnant rats were injected with two successive daily doses of 3H‐thymidine form gestational days 12 and 13 (E12 + 13) until the day before parturition (E21 + 22). In adult progeny of the injected rats the proportion of neurons generated on specific embryonic days was determined quantitatively in the vestibular and auditory nuclei of the upper medulla. In the vestibular nuclei, neurons are generated between days E11 and E15 in an overlapping sequential order, yielding a lateral‐to‐medial and a rostral‐to‐caudal internuclear gradient. In the lateral vestibular nucleus peak production time is day E12; in the superior nucleus, E13; in the inferior nucleus, E13 and E14; and in the medial nucleus, E14. The early generation of neurons of the lateral vestibular nucleus may reflect the early differentiation of the circuit from the gravity receptors (utricle) to neurons of the spinal cord controlling postural balance. The later production of neurons of the superior vestibular nucleus may reflect the subsequent differentiation of the circuit from the rotational receptors (semicircular canals) to the neurons of the brain stem controlling eye movements. The generation time of neurons of the nucleus prepositus hypoglossi overlaps with that of the medial vestibular nucleus.The neurons of the anteroventral and posteroventral cochlear nuclei are produced form days E13 to E17, with no temporal differences between the two nuclei. The neurons of the dorsal cochlear nucleus are generated over a very long time span, beginning on day E12 and extending into the postnatal period. There is a sequence in the production of neurons forming the different layers of the dorsal cochlear nucleus in the following order: pyramidal cells, cells of the inner layer, cells of the outer layer and, finally, cells of the granular layer. There is also a sequential production of neurons in four nuclei of the superior olivary complex. In the lateral trapezoid nucleus peak production time is day E12; in the medial superior olivary nucleus, day E13; in the medial trapezoid nucleus, day E15; and in the lateral superior olivary nucleus, day E16. This order yields a medial‐to‐lateral gradient in the dorsal aspect of the superior olivary complex, and a lateral‐to‐medial gradient ventrally. These mirror‐image gradients were also seen intranuclearly in the lateral superior olivary nucleus and the medial trapezoid nucleus. The cytogenetic gradients could not be related to tonotopic representation; however, they could be related to the lateral location of ipsilateral cochlear nucleus input to the lateral superior olivary nucleus and the medial location of the contralateral cochlear nucleus input to the medial trapezoid nucleus.
Glial fibrillary acidic protein in the retina of the developing albino rat: An immunoperoxidase study of paraffin‐embedded tissue
Authors: Dixon Richard G. , Eng Lawrence F. 
Published: January 2005

AbstractThe peroxidase‐anti‐peroxidase method was used on paraffin‐embedded material to demonstrate the distribution of glial fibrillary acidic (GFA) protein, an astrocyte‐specific protein, in the developing retina of the albino rat. At birth activity was scant and was confined to scattered, poorly differentiated cells in the inner retinal layers near the optic disc. At 3 days primitive astrocytes which displayed GFA protein activity were confined to the stratum opticum near the optic disc. With increasing age these cells were found at greater distances from the optic disc and began to assume the appearance of typical fibrous astrocytes. By 30 days the perikarya of these cells were confined almost exclusively to the region between the nerve fiber layer and the inner limiting membrane. The processes of these cells terminated either in suckerlike end‐feet upon blood vessels or, to a lesser extent, ended in relation to axon fascicles of the nerve fiber layer.A second population of GFA protein‐active cells existed as perivascular glia which were found upon vessels in the inner portion of the stratum opticum in young animals. In the mature retina perivascular glia were found on vessels throughout the stratum opticum and in the inner portion of the inner plexiform layer.Unequivocal staining of Müller cells or their processes was not obtained.The best staining was obtained with fixatives containing minimal concentrations of aldehydes, especially in tissue from younger animals. The fixative which gave the best preservation of cellular structure along with preservation of GFA protein antigenicity was Perfix (Fischer Scientific Company).
Monosynaptic cortical input and local axon collaterals of identified striatonigral neurons. A light and electron microscopic study using the golgi‐peroxidase transport‐degeneration procedure
Authors: Somogyi P. , Bolam J. P. , Smith A. D. 
Published: January 2005

AbstractFollowing the injection of horseradish peroxidase into the ipsilaeral substantia nigra, 36 retrogradely labelled neurons in the striatum were characterized (in three rats) by Golgi staining and gold toning: each neuron was of the medium‐size, densely spinous type. Prior to the injection of horseradish peroxidase, two of the rats had had lesions placed in the ipsilateral motor cortex, the third rat had had a lesion placed in the ipsilateral frontal and prefrontal cortex. In the electron microscope, degenerating boutons of cortical neurons were found in asymmetrical synaptic contact with the spines of proximal and distal dendrites of all six of the identified striatonigral neurons that were studied. Some of the degenerating boutons were small (diameter 0.1–0.3 μ), while others were larger (1–2 μ). An individual dendrite of a striatonigral neuron was in synaptic contact with very few degenerating boutonsLocal axon collaterals im the striatum could be traced from two of the identified striatonigral neurons that received degenerating cortical boutons. These were studied in the electron microscope; their boutons formed symmetrical synapses with spines or dendritic shafts of other striatal neurons. The synaptic boutons contained large, clear, round and pleomorphic vesicles. The postsynaptic targets of these boutons morphologically resemble the dendrites of medium‐size spiny neuronsIt is concluded that afferents from the cortex make monosynaptic contact with the dendritic spines of medium‐size spiny striatonigral neurons and that such neurons have local axon collaterals in the striatum that form synapses with other spiny neurons.
Substrate pathways demonstrated by transplanted mauthner axons
Authors: Katz Michael J. , Lasek Raymond J. 
Published: January 2005

AbstractA substrate pathway is a set of aligned guidance cues. (Such cues may be either cells or molecules). CNS substrate pathways can be demonstrated by transplanting axons to different starting locations. The stereotyped routes of transplanted axons will then demonstrate the locations of effective substrate pathways. To map CNS substrate pathways, Mauthner axons were transplanted to vaious unnatural locations along the CNS of Xenopus embryos. The routes of 24 experimental Mauthner axons were traced. Twenty‐one of these axons grew along parts of a stereotyped route extending in the ventral marginal zone from the caudal diencephalon through the spinal cord. This ventral substrate pathway ran the length of the basal plate; thus, we call it a basal substrate pathway. One experimental Mauthner axon grew along the alar substrate pathway previously demonstrated by transplanted optic axons. The demonstrations of the alar and the basal substrate pathways suggest that during development a few long substrate pathways organize the overall layout of the long tracts of the CNS. We propose that the pattern of the earliest CNS substrate pathways is established in the neural plate and is topologically preserved as the neural plate rolls into a neural tube. This pattern may be manifest as the three‐dimensional organization of the early marginal zones formed by the peripheral processes (the endfeet) of certain developing ependyma and radial glia. Subsequently, the detailed anatomy of the axon tracts and the specific terminations of individual axons are probably determined by other local chemical cues.
Immunohistochemical localization of the 150K neurofilament protein in the rat and the rabbit
Authors: Dahl D. , Bignami A. , Bich N. T. , Chi N. H. 
Published: January 2005

AbstractAntisera to the 150K‐dalton polypeptide of the bovine neurofilament triplet and chicken neurofilament antisera reacting with the 70K protein in isolated bovine brain filaments stained the same structures in rat cerebellum by immunofluorescence and peroxidase‐antiperoxidase methods, that is Purkinje cell baskets, thin nerve fibers in the lower half of the molecular layer and myelinated axons. The 150K bovine neurofilament antisera did not stain large motor neurons in the anterior horns of the spinal cord in rat and rabbit, nor aluminum‐induced neurofibrillary tangles in the rabbit. All these structures were demonstrated by the chicken neurofilament antisera and by silver neurofibrillary methods. IDPN‐induced axonal balloons containing accumulations of neurofilaments were equally well stained by bovine 150K and chicken neurofilament antisera. These data suggest that the 150K polypeptide of the neurofilament triplet is not a subunit of the neurofilament core and probably plays a role in axonal transport.
An immunohistochemical study of the organization of catecholaminergic cells and terminal fields in the paraventricular and supraoptic nuclei of the hypothalamus
Authors: Swanson L. W. , Sawchenko P. E. , Bérod A. , Hartman B. K. , Helle K. B. , Vanorden D. E. 
Published: January 2005

AbstractThe distribution of catecholaminergic fibers and cell bodies in the paraventricular and supraoptic nuclei of the hypothalamus was investigated with immunohistochemical methods in the adult albino rat. Sections through the nuclei were stained with antisera to the catecholamine synthesizing enzymes tyrosine hydroxylase (TH), dopamine‐ß‐hydroxylase (DBH), and phenylethanolamine‐N‐methyltransferase (PNMT). The results suggest that adrenergic (PNMT‐stained) fibers innervate the entire parvocellular division of the paraventricular nucleus, although the highest density of fibers was found in the medial part of the division. Only widely scattered adrenergic fibers are found in the magnocellular division of the nucleus and in the supraoptic nucleus. Noradrenergic fibers appear to innervate the periventricular zone of the paraventricular nucleus and those parts of the paraventricular and supraoptic nuclei that contain predominantly vasopressinergic neurons in both the normal and in the homozygous Brattleboro rat. Significant numbers—somewhat more than 500—of dopaminergic (TH‐stained) neurons are found in the paraventricular nucleus; the cells are distributed throughout the nucleus but are concentrated in the medial and periventricular parts of the parvocellular division. Double‐labeling experiments with the retrogradely transported tracer true blue indicate that between 4% and 8% of the dopaminergic neurons in the paraventricular nucleus project to the region of the dorsal vagal complex and/or to thoracic levels of the spinal cord. It is concluded that adrenergic inputs to the paraventricular nucleus may influence cells that project to the median eminence and to preganglionic autonomic cell groups in the medulla and spinal cord. Noradrenergic inputs to the supraoptic and paraventricular nuclei may influence primarily vasopressinergic cells that project to the posterior lobe of the pituitary, as well as cells in the periventricular part of the paraventricular nucleus that project to the median eminence.
The genesis of efferent connections from the visual cortex of the fetal rhesus monkey
Authors: Shatz Carla J. , Rakic Pasko 
Published: January 2005

AbstractThe prenatal development of the cortical projections to the dorsal lateral geniculate nucleus (LGN), superior colliculus (SC) and pulvinar was studied by autoradiography of orthogradely transported 3H‐proline injected into the occipital cortex of fetal rhesus monkeys aged from embryonic day 63 (E63) to E95. Differentiation of pyramidal neurons situated in the infragranular strata of the cortical plate (prospective layers 5 and 6, which give rise to these efferent projections) was also examined in Golgi preparations prepared from specimens of corresponding embryonic ages.In autoradiographs of the E63 fetus, no radioactive label was seen in subcortical structures. In two specimens injected around E70, label was present in the prospective magnocellular layers of the LGN and within the immediately surrounding cell‐poor zones. At these young fetal ages, the presence of topographic order in the corticogeniculate projection could not be determined due to the large size of the injection sites relative to the small cerebral vesicles. By E84 the portion of the prospective parvocellular layers adjacent to the white matter also contained label which was characteristically wedge‐shaped and appropriately located with respect to the site of the cortical injection, suggesting that topographic order is established. In the oldest fetus (E95) label in the LGN assumed a configuration similar to that seen in the adult. The cortical projection also invades the SC and pulvinar around E70. In the SC, label was initially confined to the stratum opticum, but by E84 it extended into the superficial gray. Thus, all known classes of efferent pathways from the visual cortex to subcortical structures are present by the middle of the 165‐day gestational period in rhesus monkey.The one‐month period, E63–E97, during which these efferent visual connections are established is characterized by the considerable growth and increased complexity of the dendritic arborization of pyramidal cells in the infragranular cortical layers of area 17. Thus the development of visual cortical efferents occurs in rough synchrony with the genesis of the afferent pathway from the LGN (Rakic, '76a; '79) and with the onset of morphological differentiation of pyramidal neurons in the infragranular cortical layers.
Sex differences in dendritic morphology of a song control nucleus in the canary: A quantitative Golgi study
Authors: Devoogd Timothy J. , Nottebohm Fernando 
Published: January 2005

AbstractSinging in the canary is a learned male behavior controlled predominantly by nuclei in the left hemisphere (Nottebohm and Nottebohm, '76; Nottebohm et al., '76; Nottebohm, '77). These nuclei are several times larger in males than in females (Nottebohm and Arnold, '76). One of the telencephalic song control nuclei, robustus archistriatalis (RA), was examined in Golgi‐stained tissue sections from the left and right hemispheres of male and female canaries. At least four cell classes were present in each sex. One of these cell classes was further studied with a variety of quantitative techniques. No hemispheric differences were seen in either sex. However, dendrites from male cells tend to branch and end further from the cell body than do dendrites from female cells. This differences is seen most clearly when serial sections are used to reconstruct the entire dendritic tree.
Evidence for a catecholaminergic projection to area X in the zebra finch
Authors: Lewis James W. , Ryan Susan M. , Arnold Arthur P. , Butcher Larry L. 
Published: January 2005

AbstractIn the zebra finch (Poephila guttata), horseradish peroxidase injected into or near Area X of the lobus parolfactorius (LPO) is transported to cell bodies in ipsilateral hyperstriatum ventrale pars caudale (HVc), area ventralis of Tsai (AVT), and nucleus tegmenti pedunculo‐pontinus, pars compacta (TPc). Area X, LPO, and paleostriatum augmentatum (PA) all contain a dense network of catecholamine‐containing axons and nerve terminals, as determined in histofluorescence studies. Cell bodies in AVT and TPc contain catecholamines; lesions of TPc greatly reduce or abolish catecholamine fluorescence in PA, and a lesion of AVT eliminates histofluorescence in LPO, including Area X. The anatomical location and catecholaminergic projection from AVT suggest that LPO‐Area X may be the avian homolog of the mammalian nucleus accumbens, olfactory tubercle, and/or rostromedial caudate.
The distribution of commissural terminations in somatosensory areas I and II of the grey squirrel
Authors: Gould Harry J. , Kaas Jon H. 
Published: January 2005

AbstractThe topographic distribution of somesthetic interhemispheric projections was studied in grey squirrels using the Fink‐Heimer technique following large aspiration lesions of the corpus callosum. On the day of perfusion, receptive fields were determined for microelectrode recording sites in the first, S I, and second, S II, somatosensory areas of cortex, and small electrolytic lesions were made in order to identify some of these sites in prepared brain sections. The cortex was then separated from the rest of the brain, flattened, and cut parallel, so that with the aid of the reference lesions, the total pattern of degeneration could be related to a surface view of the brain and to previous electrophysiological maps of S I (Sur et al., '78) and S II (Nelson et al., '79). The results show that callosal terminations are unevenly distributed in S I and S II, and suggest that there are several categories of callosal inputs to S I. A major region of terminations is in the architectonically distinct “unresponsive zone” within SI, and perhaps in other similar, but narrower, specialized zones within and bordering S I, as previously described in rats (Ryugo and Killackey, '75; Wise and Jones, '76, '78; Akers and Killackey, '78). Other callosal projections terminate within the responsive regions of S I. These regions include at least some of the representation of the body midline, most clearly the midline of the representations of the upper and lower face, as well as regions unrelated to the midline of the body. Most or all of the S I cortex responsive to stimuli away from the midline on the upper and lower lips, the mystacial vibrissae, and the glabrous forepaw was almost free of direct callosal terminations. Except for a central core region, most of S II appears to receive a moderate distribution of callosal inputs.
The aberrant retino‐retinal projection during optic nerve regeneration in the frog. II. Anterograde labeling with horseradish peroxidase
Authors: Bohn Ronald C. , Stelzner Dennis J. 
Published: January 2005

AbstractPrevious experiments have shown that a substantial number of regenerating optic axons in adult frogs (Rana pipiens) are misrouted into the opposite optic nerve and retina during early stages of regeneration. This projection is maximal at 5 and 6 weeks after optic nerve crush. To further characterize this anomalous projection, small quantities of horseradish peroxidase (HRP) were injected into the right eye or right optic nerve 5 or 6 weeks after right optic nerve crush. Twenty‐four hours later the animals were killed and regenerating axons anterogradely filled with HRP were reacted with the tetramethyl‐benzidine method or a diaminobenzidine‐CoCl2 method. Serial reconstruction tracing the course of individual axons through the optic chiasm showed that few of the axons projecting into the opposite optic nerve were collaterals of axons projecting centrally. Instead, the majority of labeled axons misdirected into the opposite nerve or contributing to an expanded projection into the ipsilateral optic tract turned out of the chiasm without branching. Many of the labeled regenerating axons had unusual trajectories within the chiasm, making abrupt turns or changing their direction of growth. Most of the axons misrouted into the opposite nerve came from portions of the chiasm nearest to the nerve of the other eye. In three of eight frogs with an intact optic nerve, a small number of HRP‐labeled axons were found in the left nerve after right nerve injection, but there was no indication that these axons reached the left eye. The results from this investigation suggest that the most parsimonious explanation for the chiasmal misrouting of regenerating frog optic axons is that axons are mechanically deflected into inappropriate pathways.
A Golgi study on the globus pallidus of the mouse
Authors: Iwahori Nobuharu , Mizuno Noboru 
Published: January 2005

AbstractThe globus pallidus (GP) of the mouse was studied by the rapid Golgi silver impregnation method. The GP was composed of large and mediumsized neurons. The large neurons had stellate cell bodies with a mean diameter of 25 μm by 28 μm and five to seven primary dendrites. The somato of the mediumsized neurons were spindle or fusiform in shape, measured 19 μm by 27 μm in average and emitted three to five primary dendrites. The large neurons were located mainly in the central part of the GP, whereas the medium‐sized neurons were observed in the peripheral part of the GP. Some GP neurons extended their dendrites into the caudatoputamen complex, sublenticular region or internal capsule. The axons of the GP neurons were seen most frequently to course medially or mediocaudally and to enter the internal capsule or fiber bundles traversing the GP; they were rarely observed to run laterally and to travel into the caudatoputamen complex. Some axons of the GP neurons were also observed to emit intra‐ or extra‐nuclear collaterals extending into the sublenticular region.Four groups of afferent fibers to the GP were observed; (1) fibers descending within the internal capsule or caudatoputamen complex to terminate or to give axon‐collaterals to the GP; (2) fibers ascending within the internal capsule or fiber bundles traversing the GP to enter the GP from its medial aspects; (3) fibers traversing the internal capsule laterally to terminate in the GP; and (4) fibers running dorsally through the sublenticular region to terminate in the GP. In addition to these four groups of afferent fibers, terminal branches were seen to arise numerously from many fibers running through the GP.
Acetylcholinesterase‐positive fibers and cell bodies in the cochlear nuclei of normal and reeler mutant mice
Authors: Martin Michael R. 
Published: January 2005

AbstractSections from the cochlear nuclei of normal and reeler mutant mice were treated by the method of Karnovsky and Roots ('64) for the demonstration of cholinesterase activity. In one group of controls ethopropazine was used to inhibit pseudocholinesterases and in another group BW 284C 51 was used to inhibit acetylcholinesterase (AChE). The distribution of AChE‐positive fibers in the normal mouse is given. The reeler mutant mouse differs from the normal in that there are no AChE‐positive fibers in the dorsal nucleus, very few in the granule cell layer separating the dorsal from ventral nuclei, none in the granule cell layer covering the lateral aspect of the ventral nucleus, and the number in the posteroventral and caudal anteroventral nuclei are greatly reduced. Perisomatic terminals, small and large terminal boutons, and boutons en passant are present in both normal and reeler mutant mice. AChE‐positive cell bodies are found in the deep region of the dorsal nucleus, the rostral part of the posteroventral nucleus, and the anteroventral nuclueus of both normal and reeler mutant mice. The observations in the normal mouse are compared to the distribution of AChE‐positive fibers and the types of terminals formed by noncochlear afferents in other species. Several possible causes of the lesion of the AChE‐positive fibers in the reeler mutant mouse are considered.