bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasticity of spinal systems after unilateral lumbosacral dorsal rhizotomy in the adult rat
Authors: Wang Shwun‐De , Goldberger Michael E. , Murray Marion 
Published: January 2005

AbstractPlasticity of spinal systems in response to lumbosacral deafferentation has previously been described for the cat, by using immunocytochemistry to demonstrate plasticity of tachykinin systems and degeneration methods to demonstrate plasticity of descending systems. In this study, we describe the response to lumbosacral deafferentation in the adult rat. Application of immunocytochemical methods to visualize tachykinins (predominantly substance P [SP]), serotonin (5‐HT), and dopamine B‐hydroxylase (DBH), the synthesizing enzyme for norepinephrine, permits us to compare the response of SP systems in rat and cat spinal cord and to examine the response of two descending systems, serotoninergic and noradrenergic, to deafferentation. We used image analysis of light microscopic preparations to quantify the immunoreaction product in the spinal cord in order to estimate the magnitude, time course and localization of changes induced by the lesion. The distribution of SP, serotoninergic (5‐HT), and noradrenergic staining in the spinal cord of rat is very similar to that of the cat. Unilateral lumbosacral rhizotomy elicits a partial depletion, followed by a partial replacement of tachykinin immunoreactivity in laminae I and II. This response was similar to that described for the cat, although characterized by a longer time course, and, as in the cat, is likely due to plasticity of tachykinin containing interneurons. The same lesion elicits no depletion but a marked and permanent increase in 5‐HT immunoreactivity in laminae I and II, which develops more rapidly than the response by the SP system. These results indicate sprouting or increased production of SP and 5‐HT in response to deafferentation. No change was seen in DBH immunoreactivity, indicating that the noradrenergic system does not show plasticity in response to deafferentation. Our results demonstrate that dorsal rhizotomy evokes different effects in different systems in the adult spinal cord of the rat and thus suggests that the response of undamaged pathways to partial denervation of their target is regulated rather than random.
Expression of choline acetyltransferase and nerve growth factor receptor within hypoglossal motoneurons following nerve injury
Authors: Armstrong David M. , Brady Roseann , Hersh Louis B. , Hayes Robert C. , Wiley Ronald G. 
Published: January 2005

AbstractIn the present study we employed light microscopic immunocytochemical techniques in order to investigate the temporal response of choline acetyltransferase (ChAT) and nerve growth factor receptor (NGFr) within hypoglossal motoneurons following unilateral transection or crushing of the XII nerve or after intraneural injections of ricin into the nerve. In control rats (i.e., sham operated) virtually all the motoneurons of the XII nucleus displayed intense immunolabeling for ChAT and were devoid of NGFr immunoreactivity. As early as 3 days post‐operative the intensity and the number of ChAT‐labeled neurons were reduced on the axotomized side compared to the non‐lesioned side. This decrease was maximal approximately two weeks post‐operative when virtually no ChAT‐labeled cells were present on the lesioned side. In contrast, no loss of hypoglossal neurons was found using Nissl stains. This absence of ChAT immunolabeling persisted for several days, yet by 30 days many of the motoneurons had begun to re‐express the enzyme.In contrast to the decrease in ChAT immunoreactivity, transection of the XII nerve also resulted in the expression of NGFr immunoreactivity within the lesioned motoneurons. This response was detected as early as one day post‐operatively and continued throughout all time points thus far examined including times after many of the motoneurons had begun to re‐express ChAT.Crushing of the XII nerve effected the expression of ChAT and NGFr in a manner comparable to, yet less intense than, that observed following transection.Ricin injected directly into the XII nerve resulted in the loss of hypoglossal motoneurons as demonstrated both in immunohistochemical and Nissl‐stained tissue preparations. The cell loss was readily apparent 3 days post‐operatively, and ChAT immunoreactivity permanently disappeared. NGFr immunolabeling was seen only in scattered surviving neurons but not in ricin poisoned cells.The possible mechanisms underlying the differential expression of ChAT and NGFr are discussed.
Source of sexually dimorphic galanin‐like immunoreactive projections in the teleost fish Poecilia latipinna
Authors: Cornbrooks Ellen B. , Parsons Rodney L. 
Published: January 2005

AbstractA galaninlike peptide has a sexually dimorphic distribution in the teleost fish, the sailfin molly. An extensive system of galanin‐like immunoreactive (GAL‐LI) fibers has been described in the brainstem and spinal cord of the male molly, which is absent in the female (Cornbrooks and Parsons, companion paper). As GAL‐LI in the mammalian spinal cord has been localized to neurons of origin in the dorsal root ganglia and dorsal and ventral horns, the present study was undertaken to determine whether the sexually dimorphic GAL‐LI in the male molly may originate in part from corresponding sources in this species.Colchicine treatments of the spinal cord and dorsal root ganglia did not result in GAL‐LI staining in neuronal somata in these regions. Following complete transection of the spinal cord and at any level of the spinal cord, there was a complete absence of GAL‐LI caudal to the lesion site. In fish that received unilateral spinal transection, there was a loss of GAL‐LI ipsilateral and caudal to the lesion. Finally, in fish that received lesions in the rostral hypothalamus, there was a complete loss of GAL‐LI in the sexually dimorphic fiber system in the brainstem and spinal cord, but not in non‐dimorphic GAL‐LI regions of the brainstem. Thus the sexually dimorphic fiber system in the male molly may originate in neurons of the preoptic nucleus that are sexually dimorphic for a GAL‐LI peptide. This preoptico‐spinal pathway may mediate sex‐specific behaviors in this species.
Retinal afferents to the tectum opticum and the nucleus opticus principalis thalami in the pigeon
Authors: Remy Monika , Güntürkün Onur 
Published: January 2005

AbstractThe retinal afferents of the tectum opticum and the n. opticus principalis thalami (OPT) were studied with fluorescent tracers in pigeons. Injections into the tectum opticum revealed topographically related areas of high density labelling in the contralateral retina. In these areas up to 15,000 cells/mm2 were labelled. After tectal injections the soma sizes of labelled retinal ganglion cells in the area centralis ranged from 5 to 23 μm with a mean of 7.5 μm. Afferents from the ipsilateral retina could not be demonstrated. Injections into the OPT labelled neurons throughout the retina without a clear topographical relation to the locus of injection. The density never exceeded 150 cells per mm2. The soma size range was 8 to 35 μm with a mean of 14.6 μm. Independently of the injection area within the OPT, the red field in the dorsotemporal retina was always extremely sparsely labelled. The number of labelled ganglion cells in this area never exceeded 25 neurons/mm2. After OPT injections the average density of labelling per unit area was six times higher in the yellow than in the red field. The results confirm previous reports of a massive and topographically organized retinal projection onto the optic tectum. The projection onto the OPT was clearly smaller and with the retrograde tracing techniques in use, an orderly topography has not been demonstrated. The paucity of red field projections onto the OPT suggests that the role of the thalamofugal pathway in binocular integration is very limited.
Histochemical demonstration of zinc in the hippocampal region of the domestic pig: II. Subiculum and hippocampus
Authors: Holm Ida E. , Geneser Finn A. 
Published: January 2005

AbstractThe distribution of zinc has been described in two areas of the hippocampal region of the domestic pig, viz., the subiculum and the hippocampus. Zinc was demonstrated histochemically according to the Neo‐Timm method, a modification of the sulphide‐silver procedure. In each of the examined areas the staining displayed a distinctly stratified pattern which has been compared in detail to fields and layers defined on the basis of cyto‐ and fibroarchitecture, resulting in a combined chemo‐ and cytoarchitectonic map. Most of the staining was confined to the neuropil, but a considerable number of stained nerve cell bodies were seen in both the subiculum and the hippocampus.In the subiculum, the plexiform layer was divided into a superficial, weakly stained subzone and a deep, better stained subzone. The cell layer was generally well stained, but displayed a complex staining pattern with differences in staining intensity of both the cell bodies and neuropil. In regio superior of the hippocampus, the stratum moleculare appeared weakly stained, with the exception of a tapering process of more darkly stained tissue projecting from the plexiform layer of the subiculum into the deepest part of the layer. Stratum radiatum and the superficial subzone of stratum oriens showed a weak staining intensity, contrasting to the relatively darkly stained pyramidal cell layer and the intensely stained deep subzone of stratum oriens. In regio inferior, the stratum moleculare was divided into a moderately stained superficial part and an unstained deep part. Stratum radiatum and stratum oriens both appeared weakly stained. The layer of mossy fibers was very intensely stained and appeared almost homogeneously black in its main suprapyramidal part, whereas the infrapyramidal part was looser in character. The pyramidal cell layer was darker than in regio superior.The distribution of zinc in the pig was compared with that in the guinea pig and rat, described previously. The staining pattern is fundamentally similar in all three species, though notable species‐specific traits do exist.
Synaptic organization of columnar elements in the lamina of the wild type in Drosophila melanogaster
Authors: Meinertzhagen I. A. , O'Neil S. D. 
Published: January 2005

AbstractThe synaptic connections within the lamina, the first of the optic neuropiles underlying the insect's compound eye, have been little studied in Drosophila melanogaster until now, despite the genetic advantages of this animal. Here we report the reconstruction through its entire depth of one of the lamina modules, or cartridges, of a female wild‐type Drosophila, for which a series of EM cross sections was analysed at levels extending from the retinal basement membrane to the first optic chiasma. A complete, comprehensive catalogue of the synaptic connections of all columnar elements has been compiled from this single series, confirmed from comparisons with less completely photographed cartridges. Combinations of the 12 types of cartridge neurons form divergent multiple‐contact synapses (dyads, triads, and tetrads) throughout the lamina's depth. These 12 neuron types include 11 narrow‐field elements (one class of receptor terminal, R1–R6, providing input to the cartridge; two types of long visual fiber from the ommatidium, R7 and R8; five types of monopolar cell, L1–5; and three types of medulla cell–two centrifugal neurons C2 and C3, and a third, T1) as well as a wide‐field intrinsic or amacrine cell. Connections within the lamina formed by L4 from two adjacent cartridges (posterodorsal and posteroventral) contribute to the matrix of connections. In addition, connections of at least one other wide‐field element have also been incorporated.
Inventory and distribution of synapses of identified uniglomerular projection neurons in the antennal lobe of Periplaneta americana
Authors: Malun Dagmar 
Published: January 2005

AbstractUniglomerular projection neurons in the antennal lobe of Periplaneta americana, the axons of which connect the lobe to the protocerebrum, were labeled by intracellular injection of Lucifer Yellow or biocytin. The fine structure of individual neurons within the antennal lobe was examined after the injected substances had been converted (by immunohistochemical or histochemical treatment) to electron microscopically visible reaction products. Seven projection neurons were investigated, including attractant neurons, with dendritic arbors in the macroglomerulus, and projection neurons of normal‐sized glomeruli. From reconstructions of thin serial sections and examination of additional processes present at various places in the arborization regions, the distribution of synapses within the glomeruli was inferred.Although the projection neurons differ from one another in their glomerular arborization patterns, they are very similar in the spatial segregation of their input and output synapses within the arborization. Output synapses are found on the thick part of the fiber near its site of entry into the glomerulus, as well as in regions within the glomerulus where the neuron has begun to ramify into thinner fibers. In the latter regions, the many output synapses are accompanied by occasional input synapses; hence these are regarded as transitional regions. At the terminal arbors only input synapses were found. This suggests that neurons with dense terminal arborizations receive particularly numerous inputs in these regions.The large number of input synapses reflects the high degree of convergence of afferents onto projection neurons previously demonstrated physiologically. However, the presence of numerous output synapses indicates that projection neurons not only transport sensory information into the protocerebrum but are also a major component of the neuronal circuitry within the antennal lobe.
Distribution of estrogen receptor‐immunoreactive cells in the forebrain of the female guinea pig
Authors: Doncarlos Lydia L. , Monroy E. , Morrell J. I. 
Published: January 2005

AbstractWe mapped the distribution of estrogen receptor‐containing cells in the forebrain of the adult female guinea pig. Cellular estrogen receptor content was detected using monoclonal antibody H222, directed against the estrogen receptor, and the avidin‐biotin method with nickel‐intensified diaminobenzidine as the chromagen. A complete set of deletion, titration, and adsorption controls established the specificity of the staining. The most dense collections of estrogen receptor‐immunoreactive cells were found in medial preoptic, medial hypothalamic, and limbic nuclei (amygdala, bed nucleus of the stria terminals, lateral septum). Numerous estrogen receptor‐immunoreactive cells were also found in additional, specific subregions of the remainder of the preoptic area, hypothalamus, and limbic system, and also in the midbrain (central gray). Elsewhere, estrogen receptor‐immunoreactive cells were present in smaller numbers or were absent. This map confirms and extends previous maps based on estrogen binding. The majority of estrogen receptor‐immunoreactive cells are found in areas known to be involved in some aspect of reproduction. In addition, many estrogen receptor‐immunoreactive cells are found in areas not typically considered to have a primary role in reproductive behavior or neuroendocrine function.
Orientation discrimination in the cat: Its cortical locus. I. Areas 17 and 18
Authors: Vandenbussche E. , Sprague J. M. , De Weerd P. , Orban G. A. 
Published: January 2005

AbstractAn elementary unit of visual pattern and form perception is thought to be the orientation of edges; this element has been studied extensively by neurophysiologists using oriented line segments or bars. These same stimuli have been used in the present study to measure threshold discriminations in cats before and after cortical lesions of areas 17 and/or 18. Control experiments showed that the discriminations were made by using a single cue, orientation, and that other stimulus parameters, width, length and contrast of the bar, were optimized.The extent of the lesions was evaluated anatomically from cell and fiber stained sections through cortex and thalamus, matched to retinotopic maps of Tusa et al. (Cortical Sensory Organization, Vol. 2, Humana Press, pp. 1–31, '81) and Sanderson (Journal of Comparative Neurology 143:101–118, '71), and physiologically from visual field position of receptive fields of cells recorded in areas neighboring the lesions.Lesions involving area 17 and large parts of area 18 produced a marked deficit in orientation discrimination which included a loss in retention, and after retraining a substantial increase in thresholds for up to 3 years when tested with long bars. There was no recovery of discrimination when the animals were tested with short bars.Lesions which involved area 17 plus small parts of 18, or lesions of areas 18 and 19, produced no retention deficit and resulted in an increase in thresholds only at low contrast and narrow width.These experiments revealed an excellent correlation between lesion locus and size and behavioral deficit. They indicate that the cortical representation of bar orientation used for discrimination is distributed within and across areas 17 and 18. The spread of the distribution depends on other stimulus parameters such as bar width and length. Furthermore the experiments show that neither the most narrowly tuned cells nor the X‐cell system is required for fine orientation discrimination of a long bar.
Anatomy and physiology of spiking local and intersegmental interneurons in the median neuroblast lineage of the grasshopper
Authors: Thompson Karen J. , Siegler Melody V. S. 
Published: January 2005

AbstractThe range of anatomical and physiological properties in the adult progeny of an identified neuroblast was investigated. Some 80–90 adult neurons constitute the dorsal unpaired median (DUM) group of the grasshopper metathoracic ganglion. Within the group are efferent, octopaminergic neurons with large cell bodies and overshooting action potentials. Our objective was to determine the properties of the neurons with small cell bodies that make up the majority of the clone, some 60–70 neurons, about which scant information was available. The small DUM neurons have cell body diameters of 10–20 μm and stain with antibodies to GABA (Thompson and Siegler, '89: Proc. Soc. Neurosci. 15:1296 (abstr.); Witten and Truman, '89: Proc. Soc. Neurosci. 15:365 (abstr.)). By employing intracellular electrophysiological and morphological techniques, we have established that the small DUM neurons are spiking interneurons, expressing passively conducted action potentials in the cell body. They fall into two basic classes: local interneurons with bilateral branches in the auditory neuropiles, and intersegmental interneurons with bilateral branches widespread in the metathoracic ganglion and axons traveling in both anterior connectives. The local interneurons typically respond to sound, whereas the intersegmental interneurons selectively respond to wind on the head or to generalized movements by the animal. Primary neurites of small and large DUM neurons enter the neuropil in a bundle, but the neurites of DUM interneurons are more posterior and have a separate trajectory from those of the efferent DUM neurons once in the ganglion core. A model is presented for the sequential development of efferent, local, and intersegmental DUM neurons from the median neuroblast.
Junctional specializations between growth cones and glia in the developing rat pyramidal tract: Synapse‐like contacts and invaginations
Authors: Gorgels T. G. M. F. 
Published: January 2005

AbstractThe ultrastructure of contacts between axonal growth cones and glial cells in the developing pyramidal tract was examined by serial sectioning at the third cervical spinal cord segment in 0‐, 2‐, and 4‐day‐old rats. Junctional specializations, composed of synapse‐like contacts and invaginations, were frequently observed at the contact zone between growth cones and glial elements. The synapse‐like contacts consist of clear, round vesicles of 43 ± 6 nm in the presynaptic growth cone, a pre‐ and a postsynaptic density, separated by a cleft of 12.1 ± 0.9 nm. The invaginations consist of small protrusions of the growth cone into the glial element. The invaginated glial membrane is coated. Within the glial element, close to the invagination, frequently organelles were observed that closely resemble endosomes and prelysosomes. Therefore, it is suggested that the invagination represents a stage in endocytosis or possibly phagocytosis of the protruding part of the growth cone by the glial cell. The junctional specializations are formed by growth cones and, less frequently, by axon shafts. The targets of these specialized contacts are, in general, immature glial cells located within the tract area. Occasionally, however, invaginations were also observed into myelinating oligodendrocytes, suggesting that the population of immature target cells includes oligodendrocyte precursors.With regard to the functional significance of these temporary growth cone‐glial contacts, several possibilities are discussed, including the suggestion that outgrowing pyramidal tract axons provide immature glial cells with chemical messages, which may influence the timing of glial cell maturation in the tract.
Acetylcholinesterase‐rich neurons of the human cerebral cortex: Cytoarchitectonic and ontogenetic patterns of distribution
Authors: Mesulam M‐Marsel , Geula Changiz 
Published: January 2005

AbstractLayers 3 and 5 of the adult human cerebral cortex contain a very large number of pyramidal neurons that express intense acetylcholinesterase (AChE) enzymatic activity and AChE‐like immunoreactivity. The density of these neurons is high in motor, premotor, and neocortical association areas but quite low in paralimbic cortex. Those AChE‐rich neurons are located predominantly within layer 3 in the premotor and association cortex, within layer 5 in the non‐isocortical components of the paralimbic cortex, and are equally prominent in layers 3 and 5 in the motor cortex. Almost all Betz cells in the motor cortex and up to 80% of layer 3 pyramidal neurons in some parts of the association neocortex yield an AChE‐rich staining pattern. The existence of a specific laminar and cytoarchitectonic distribution suggests that the AChE‐rich enzymatic pattern of these neurons is selectively regulated.The AChE‐rich enzymatic reactivity of the layer 3 and layer 5 neurons is not detectable during early childhood, becomes fully established during adulthood, and does not show signs of decline during advanced senescence in mentally intact individuals. The AChE activity (or enzyme synthesis) in these neurons is therefore held in check for several years during infancy and childhood and begins to be expressed at a time when the more advanced motor and cognitive skills are also being acquired.The absence of immunostaining with an antibody to choline acetyltransferase suggests that these AChE‐rich neurons are not cholinergic. The regional distribution of these AChE‐rich neurons does not parallel the regional variations of cortical cholinergic innervation. Whereas the AChE‐rich pyramidal neurons of layers 3 and 5 almost certainly represent one subgroup of cholinoceptive cortical neurons, their AChE‐rich enzymatic pattern is probably also related to a host of non‐cholinergic processes that may include maturational changes and plasticity in the adult brain.