bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuroanatomy of spastic, a behavior mutant of the mexican axolotl: Purkinje cell distribution in the adult cerebellum
Authors: Ide Charles F. , Tompkins Robert , Miszkowski Nancy 
Published: January 2005

AbstractThe spastic mutant, found in the Mexican axolotl, shows swimming coordination and equilibrium deficiencies. Histological analyses of wildtype and spastic mutant cerebella previously characterized in physiological studies revealed changes in Purkinje cell location in the mutant auricle or vestibulo‐cerebellum. Purkinje cells are “translocated” ventrally correlated with a similar translocation of vestibular single units described previously (Ide, '77). Where wild‐type Purkinje cells are distributed from the surface to a depth of 250 micrometers, mutant Purkinje cells are “crowded” between 250 and 350 micrometers. Although mutant granule cells are present, boundaries between granule cell and Purkinje cell zones are less precise in mutants. Cerebellar nucleus cells are translocated medially, failing to organize into the discrete cell group appearing in wild‐type. Cerebellar white matter tracts and fibers show changes, both in orientation with respect to the underlying tegmentum, and in fascicular organization. Obvious changes in the gross anatomy of the cerebellum are confirmed in reconstructions which define cell and fiber translocations. Thus, the spastic gene is compatible with differentiation of all cerebellar elements, but appears to alter interactions between cells, or between cells and the external milieu. Although all cell types are present in the mutant cerebellum, they fail to attain their proper positions along all three body axes.
Experimental analysis of embryogenesis of cerebellum in rat. II. Morphogenetic malformations following X‐ray irradiation on day 18 of gestation
Authors: Das Gopal D. 
Published: January 2005

AbstractRat embryso of 18 days gestation were exposed in utero to 170 R of X‐ray irradiation. Embrysos were collected six hours, 1, 2 and 3 days after irradiation, and animals of 2‐, 6‐, 15‐ and 30–day‐old postnatal age were sacrificed. Six hours after irradiation pyknosis of cells was noticed in the external granular layer along the posterior aspect of the cerebellum. Neuroblasts, destined to differentiate into Purkinje cells, were found arrested in their migratory path. During subsequent peoiods of embryogenesis the external granular layer was found recovered, and clustering of the neuroblasts was disorganized and fragmented. This abnormal clustering of neuroblasts was permanent, and the external granular layer followed the same abnormal pattern in its growth. During postnatal development the internal granular layer also was found to follow the abnormal pattern of Purkinje cell layer. These abnormal developmental events were seen to lead to malformed folia in the anterior regions of the cerebellum. In addition to it the cerebellum of X‐ray irradiated animals appeared smaller than the normal. Issues having abearing on the differential radiosensitivity of different cells, factors determining the small size of the cerebellum, and cellular events determining the morphogenetic malformations are discussed.
Indoleamine neurons and their processes in the normal rat brain and in chronic diet‐induced thiamine deficiency demonstrated by uptake of 3H‐Serotonin
Authors: Chan‐Palay Victoria 
Published: January 2005

AbstractIndoleamine structures in the brains of normal, pair‐fed control, and thiamine deficient rats are selectively localized by autoradiography following monoamine oxidase inhibition and simultaneous intraventricular infusion of 3H‐5HT (10−5 m) and cold d–1 norepinephrine (10−4 m). The locations of indoleamine neurons and their plexuses are comparable in the normal and control animals and are enumerated and mapped in detail. In addition to numerous labeled neurons in the raphe and reticular formation of pons and medulla, there are indoleamine neurons in several hypothalamic nuclei, in the mammillary, habenular, and interpeduncular nuclei. Labeled axonal plexuses occur in almost all areas of the brain but certain regions in spinal cord, medulla, midbrain, diencephalon, basal ganglia, and hippocampus are particularly rich. Thiamine deficiency causes lack of label in almost all indoleamine neurons and their processes in the midbrain and medulla; only a few dystrophic cells with hypertrophied axons are seen. In the diencephalon more indoleamine neurons and their axonal plexuses are visualized in these uptake studies. The periventricular regions of spinal cord, medulla, midbrain and diencephalon, the mammillary nuclei, habenular nuclei, and cerebellum – areas richly innervated by indoleamine axons in the normal brain – are the most severely affected. The ventricular and leptomeningeal indoleamine structures are preserved, however, and individual axons may hypertrophy. It remains to be resolved whether these changes reflect disturbances in the ability of certain indoleamine neurons to take up and retain 3H‐5HT or true neuronal degeneration.
3H estradiol in catecholamine neurons of rat brain stem: Combined localization by autoradiography and formaldehyde‐induced fluorescence
Authors: Heritage A. S. , Grant L. D. , Stumpf W. E. 
Published: January 2005

Abstract3H estradiol–17β was localized in nuclei of catecholamine (CA) neurons of the rat lower brain stem, i.e., midbrain, pons and medulla, by employing a combined formaldehyde‐induced fluorescence (FIF)‐autoradiography approach which permits the direct visualization of 3H estradiol uptake in relation to CA‐neuron perikarya and terminals. In the medulla, noradrenalin (NA)‐containing neurons in and adjacent to the nucleus (n.) reticularis lateralis (group A1) and in the vicinity of the n. tractus solitarii (group A2) concentrated 3H estradiol. In the pons, NA neurons dorsal to the n. olivaris superior (group A5), in the locus ceruleus (group A6) and ventral to the pedunculus cerebellaris superior (group A7) displayed 3H estradiol uptake. In the midbrain, dopamine (DA)‐containing neurons in the n. cuneiformis (group A8), in the zona compacta of the substantia nigra (group A9) and adjacent to the n. interpeduncularis (group A10), were not seen to concentrate 3H estradiol. This is in contrast to DA neurons in the n. arcuatus of the hypothalamus (group A12), previously reported to concentrate 3H estradiol. In addition, certain non‐CA‐containing neurons with nuclear uptake of 3H estradiol were observed to be surrounded by CA terminals in such areas as substantia grisea centralis, n. tractus solitarii and n. tractus spinalis nervi trigemini. This suggests a second mode of interaction between CA neurons and estrogen target neurons. The estradiol‐CA neuron relationships described may provide morphological substrates underlying functional interactions between estradiol and CA neurons in the rat brain.
Cell death of motoneurons in the chick embryo spinal cord. I. A light and electron microscopic study of naturally occurring and induced cell loss during development
Authors: Chu‐Wang I‐Wu , Oppenheim Ronald W. 
Published: January 2005

AbstractThe onset and sequence of cell death in the lateral motoneurons of the lumbar spinal cord of the chick embryo was studied between 4 and 18 days of incubation by light and electron microscopy. The naturally occurring degeneration of a few motoneurons begins already on day 4 of incubation, but the cell loss becomes much more frequent from day 5.5 to day 9, during which 40% of the neuron population degenerates. In the light microscope, the degenerating neurons are seen to undergo shrinkage and condensation. Ultrastructurally, two types of degeneration can be recognized. In the first, termed Type I, the polyribosomes are dissociated and appear free in the cytoplasm. Ribosomes also become detached from rough endoplasmic reticulum, although small pieces of cisternae of rough endoplasmic reticulum are still recognizable. Most of the mitochondria are vacuolized. These changes are accompanied by the appearance of a pyknotic nucleus which contains condensed chromatin masses. The most characteristic feature in what we term Type II degeneration is the striking dilatation of the endoplasmic reticulum, the nuclear envelope and the Golgi apparatus. Ribosomes still form distinctly rosette‐like polyribosomes. A few mitochondria show signs of degeneration. The nuclear profile in most cells of this type is rounded whereas the chromatin is becoming condensed. In the late stages of Type II degeneration, the dilated membrane systems break down into numerous vesicles some of which still have ribosomes attached. Only late in the sequence of Type II degeneration do polyribosomes then dissociate to free monoribosomes. The degeneration process in both types leads finally to cell death and complete cellular breakdown: the entire process being due to an autolytic mechanism. The nuclear envelope breaks down and the nuclear content becomes mixed with lytic cytoplasm. The dying cell finally either condenses into one big globule or several smaller fragmented globules. All the globular debris are highly osmiophilic and compact. Only at this stage of breakdown is the cell debris phagocytozed by radial ependymal processes and mononuclear leukocytes. The entire degenerative process in these immature neurons is strikingly rapid.In the case of induced cell death by removal of the limb bud on day 2.5, we found that both types of degeneration described above also occur in the peripherally deprived lateral motor column (LMC). The only obvious difference is that limb bud removal increases the speed and the number of cells undergoing degeneration. By day 10, about 90% of the neuron population in the deprived LMC have completely disappeared.
The development and degeneration of Purkinje cells in pcd mutant mice
Authors: Landis Story C. , Mullen Richard J. 
Published: January 2005

AbstractPurkinje cell degeneration (pcd), an autosomal recessive mutation in the mouse, causes the postnatal death of virtually all cerebellar Purkinje cells during the third and fourth postnatal week. We have compared the postnatal development of normal and pcd mutant Purkinje cells. The early deviations from normal development involve primarily the perikaryonal polysomes and endoplasmic reticulum. Many of the mutant Purkinje cells retain abnormally the basal accumulation of polysomes, a finding which permits the identification of affected animals at postnatal day 15, one week prior to the onset of behavioral abnormalities. In addition, the affected Purkinje cells possess unusual configurations of endoplasmic reticulum with associated electron‐dense particles similar to but larger than ribosomes, mature and forming intracisternal A particles and nematosomes. Before the pcd Purkinje cells degenerate they appear to receive all their appropriate synaptic contacts. Some disruption, however, of parallel fiber: Purkinje spine synaptogenesis occurs at late stages of development. Some spines lack presynaptic elements, postsynaptic thickenings are present along the dendritic shafts and parallel fibers appear to make synaptic contacts directly onto the shafts. The spectrum of early morphological changes that has been observed in pcd mutant Purkinje cells is thus far unique to this cerebellar abnormality.
The effects of undernutrition on Purkinje cell dendritic growth in the rat
Authors: McConnell P. , Berry M. 
Published: January 2005

AbstractThe effects of undernutrition on the developing cerebellum were studied in 30‐day‐old rats undernourished from birth byrestricting access to the lactating mother. These animals showed a significant reduction in cerebellar weight when compared with well‐nourished controls. Quantitative studies of the cerebeller vermis revealed a 34.2% reduction in total area, with the densityof both granule cells and Purkinje cells increased. Network analysisof Golgi‐Cox preprations indicated a significant increase in the density of dendritic fields of Purkinje cells, although there was a 37% decrease in overall network size, due to reduction inthe total number of dendritic segments, and a reduction in the length of distal segments. Topological analysis indicated that the network had developed by terminal branching, as in normal animals, butwithsome deviation from the usual purely random branching pattern.All the observed modifications may be accounted for in terms of alterations in protein synthesis and DNA synthesis ocurring in undernourished animals. This leads to alterations in the extent of the intereuronal matrix, a rdduction in the number of granule cells and direct effects in Purkinje cell metabolism, all of which influence dendritic development, although the relative impotance of each of these factors awaits precise definition.
Categories of axons in the inferior cardiac nerve of the cat
Authors: Emery Dennis G. , Foreman Robert D. , Coggeshall Richard E. 
Published: January 2005

AbstractMyelinated and unmyelinated axons in the inferior cardiac nerve of the cat were examined to determine how many axons were (1) sensory, (2) preganglionic sympathetic, and (3) postganglionic sympathetic. In one group of cats, a segment was removed from the middle of the inferior cardiac nerve as a control, and the proximal and distal stumps of the nerve were examined one week later. In another group of cats, the control segment of nerve was removed and the first thoracic white ramus communicans and sympathetic trunk were cut proximal to the stellate ganglion, followed in one week by examination of the proximal and distal stumps of the inferior cardiac nerve. In still another group of cats, the first five thoracic spinal nerves were cut just distal to the dorsal root ganglion. The counts of myelinated and unmyelinated axons after these surgical procedures indicated that, in the cat inferior cardiac nerve, all or almost all of the approximately 30,000 unmyelinated axons and 10% of the myelinated axons are postganglionic sympathetic fibers, and that approximately 90% of the myelinated axons are sensory.
Segmental homology and variation in flexor motoneurons of the crayfish abdomen
Authors: Mittenthal Jay E. , Wine Jeffrey J. 
Published: January 2005

AbstractIn the crayfish abdomen the anterior five of six ganglia are serially homologous. The locations and sizes of motoneuron somata of the fast and slow flexor systems have been determined by axonal infusion of cobalt. The somata form three clusters, distinguished by soma position in the ganglia and course of axons in the nerve cord. For the fast flexors, the anterior group shows the greatest departure from serial homology; it has one soma in the first ganglion (G1), three in G2 and G3, two in G4, and none in G5. The medial group contains the giant motoneuron, the peripheral inhibitor, and two smaller neurons in all five ganglia. The posterior group contains four somata in G1‐G4 and three in G5. The slow flexor motoneuron somata cluster into the same three groups.Intersegmental variations in soma size and in volume of muscle innervated are positively correlated for the giant motoneuron and for the peripheral inhibitors of both fast and slow flexor muscles.Corresponding clusters of neuropilar branches of the fast flexor peripheral inhibitor can be recognized in each of the anterior five abdominal ganglia of Procambarus. Inhibitors in G1‐G5 occupy roughly corresponding positions with respect to the dorsal giant interneurons and receive similar inputs.Ganglia of the crayfish abdomen were compared by using the positions of serially homologous somata to define a mapping from each ganglion onto G2. The mappings support the conventional view that G2, G3, and G4 are typical abdominal ganglia, while G1 and G5 show special end effects.Groups of flexor motoneurons homologous to the three groups in crayfish, and to some extent homologous neurons, can be recognized in ganglia of other decapod crustacea. Groups of motoneurons that are strikingly similar to the groups in decapod crustacea appear in several orders of insects. The groups in crustacea and insects may be homologous, and corresponding groups may exist widely within the Articulata. These apparent intersegmental and interspecific homologies suggest homology of large‐scale features of ganglionic organization.
Anatomical demonstration of orientation columns in macaque monkey
Authors: Hubel David H. , Wiesel Torsten N. , Stryker Michael P. 
Published: January 2005

AbstractIn the macaque monkey striate (primary visual) cortex, the grouping of cells into ocular dominance and orientation columns leads to the prediction of highly specific spatial patterns of cellular activity in response to stimulation by lines through one or both eyes. In the pesent paper these paterns have been examined by the 2‐deoxyuglucose autoradiographic method developed by Sokoloff and his group (Kennedy et al, '76). An anesthetized monkey was given an injection of 14C 2‐deoxyglucose and then visually stimulated for 45 minues with a large array of moving vertical stripes, with both eyes open. The 14C autoradiographs of striate cortex showed vertical bands of label extending through the full cortical thickness. Layer I was at most only lightly labelled, and layers IV b and VI wee the most dense. Layer IV c (the site of terminations of most geniculate afferents) was labelled uniformly along its length, as expected from the lack of orientation specificity of units recorded in that leyer. In the other layers the pattern seen in tangential sections was complex, consisting of swirling stripes with many bifurcations and blind endings, but with occasional more regular regions whee the stripes wee roughly parallel. Interstripe distance was rather constant, at 570 μm. Ocular dominance columns were examined in this same monkey, in the same region, by injecting one eye with 3H‐proline two weeks before the deoxyglucose experiment, and preparing a second set of autoradiographs of the sections after prolonged washing to remove the 14C‐deoxyglucose. As seen in tangential sections through layer IV c, these columns had the usual stripe‐like form, with a period of 770 μm, but were simpler in their pattern than the orientation stripes, with fewer bifurcations and less swirling. A comparison of the two sets of columns in the same area showed many intersections, but no strict or consistent relationships: angles of intersection showed a distribution that was not obviously different from that expected for any two randomly superimposed sets of lines.Another monkey was stimulated with vertical stripes, but with only one eye open. Deoxyglucose autoradiographs of tangential sections showed regular uniform rows of label in layer IV c, with all the characteristic features of eye dominance columns. In the layers above and below IV c the rows in tangential view were broken up into regularly spaced patches of label, presumably representing aggregations of cells responsive to vertically oriented stimuli. The patches showed no consistent alignment across the ocular dominance rows, and indeed no such tendency would be expected, considering the complexity of the orientation columns. This pattern of labelling is again predicted from and confirms the previous physiological studies.
Connections of he visual cortex in the hedgehog (Paraechinus hypomelas). II. Corticocortical projections
Authors: Gould Harry J. , Ebner Ford F. 
Published: January 2005

AbstractCortical subdivisions based on cytoarchitectural and myeloarchitectural observation of normal tissue were correlated with the topography of corticocortical connections in the visual system of the Pakistani hedgehog. Large subpial aspiration lesions were made in both visual and non‐visual cortical regions to determine he areal limits of the corticocortical connections of the visual cortex. Subsequently, discrete electrolytic lesions were placed within the visual cortex. After appropriate survival periods, the brains were processed and stained with the Fink‐Heimer technique.The results of these studies show that the visual cortex may be subdivided into four distinct regions from lateral to medial; the lateral parastriate cortex, the lateral and medial part of striate cortex, and the medial parastriate cortex. With in these regions, interhemispheric connections between visual cortices arise mainly in the lateral striate and lateral parastriate regions and terminate in a single band within the lateral portion of the cytoarchitecturally defined striate cortex. These corticocortical projections, therefore, substantially overlap with the geniculostriate projections. Lateral striate cortex and lateral parastriate cortex project in a reciprocal fashion that correlates well with the physiologically defined mirror image representation of two retinotopic maps of the binocular visual field on cortex. These connections are reflected about a line that is closely correlated with the medial edge of the band of commissural axon terminals that is located within the lateral striate cortex, instead of corresponding exactly with the striate‐parastriate border as they do in other mammals. Medial striate cortex projects to medial parastriate cortex, indicating that the monocular portion of V I is related to a separate secondary area of cortex on the medial wall of the hemisphere.
Different patterns of cochlear innervation during the development of the kitten
Authors: Pujol R. , Carlier E. , Devigne C. 
Published: January 2005

AbstractThe postnatal development of neuro‐epithelial junctions inside the kitten cochlea has been investigated by electron microscopy, and correlated with previous electrophysiological results. Two main stages of development are described. During the first postnatal days, outer hair cells look very immature with only a few afferent endings adjoining them. The inner hair cells, on the other hand, are surrounded by numerous endings with mature afferent and efferent synapses. Thus, when the efferent olive‐cochlear system begins to function during the first postnatal days, it is days, it is able to modify only inner hair cell responses. The second postnatal week is characterized by maturation of the large efferent endings below the outer hair cells. At the same time, direct efferent connections become sparce at the level of inner hair cells. The maturation of hearing, at the receptor level, seems to proceed in two steps, one related to inner hair cells and corresponding to a gross and primitive hearing, the other related to outer hair cells and corresponding to more precise and discriminative hearing abilities.