bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibrissectomy induced changes in GAP‐43 immunoreactivity in the adult rat barrel cortex
Authors: Dunn‐Meynell A. A. , Benowitz L. I. , Levin B. E. 
Published: January 2005

AbstractWithin the rat primary somatosensory cortex, neurons responding principally to movement of each individual mystacial vibrissa are grouped together in structures termed barrels. Previous studies have examined changes in the area of cortex showing increased 2‐deoxyglucose uptake in response to vibrissal stimulation. These studies have shown that chronic removal of all but the central (C3) vibrissa in adult rats induces an enlarged representation of the remaining C3 barrel in the contralateral cortex. This increase is prevented by cortical norepinephrine depletion. The major question raised by such studies is whether such plasticity is due to structural rearrangement or unmasking of otherwise silent synapses. In this study, antibodies to GAP‐43, a presynaptic protein whose synthesis is related to neuronal development and regeneration, were used to investigate this issue. In adult rat brain, tangential sections through layer IV of the barrel receptor field normally show moderate levels of GAP‐43 immunoreactivity (GAP‐IR) in the inter‐barrel septa and low levels within the barrels themselves. The present study examined changes in the pattern of GAP‐IR from 1 to 8 weeks after vibrissectomy with sparing of C3 as an index of possible physical reorganization of cortical circuits. Quantitative analysis of the cortices of animals with unilateral vibrissectomy with sparing of C3 showed that the area of low GAP‐IR within the barrels surrounding C3 was decreased at 1 week (8.4% shrinkage; P < 0.01) and 8 weeks (12.0% shrinkage; P < 0.015), relative to the cortex ipsilateral to the surgery. Both bilateral vibrissectomy with sparing of C3 and ibotenic acid lesions of the ventrobasal thalamus produced similar results. Some evidence was also seen that the area of low GAP‐IR in the C3 barrel shrank to a similar degree after such manipulations. Cortical norepinephrine depletion had no apparent effect on vibrissectomy‐induced GAP‐IR changes. These results suggest that removal of vibrissal input to the adult rat barrel cortex produces transynaptic induction of axonal sprouting within the barrel cortex.
Normal development and effects of deafferentation on the morphology of superior collicular neurons projecting to the lateral posterior nucleus in hamster
Authors: Mooney Richard D. , Savage Steven V. , Hobler Scott , King Tod D. , Rhoades Robert W. 
Published: January 2005

AbstractVisually responsive neurons in the superficial layers of the hamster's superior colliculus (SC) can be divided into distinct morphological and functional classes. In the preceding paper (Mooney et al., '91), we showed that neonatal enucleation has only slight and insignificant effects upon the structural characteristics of cells within a given class, but results in a significant reduction of neurons (narrow and widefield vertical cells) with dorsally directed dendritic arbors. In an effort to determine whether this change reflected differential transneuronal degeneration of these cell types or alterations in the dendritic arbors of surviving cells, this study re‐examined this issue by restricting the analysis to a specific and relatively homogeneous subpopulation of superficial layer neurons, those that project to the lateral posterior nucleus (LP). Physiological recordings demonstrated that most (64.7%) tecto‐LP cells in neonatally enucleated hamsters develop somatosensory receptive fields. The combination of retrograde tracing and injection of cells with Lucifer yellow in a fixed slice preparation demonstrated that nearly 75% of tecto‐LP cells in normal adult hamsters are widefield vertical cells while less than 25% of the neurons filled in neonatally enucleated adults are in this class. Most of the tecto‐LP cells in the neonatally enucleated adult hamsters were either horizontal cells (19.5%), giant stellate cells (24.6%), or had dendrites that were directed only toward the deep SC laminae (10.3%). Differential enucleation‐induced cell death could not account for all of these changes. Tecto‐LP neurons were retrogradely labelled with the carbocyanine dye, Di‐I, in hamsters on postnatal day (P‐) 0 (the day of birth) through P‐10. As early as P‐0, most retrogradely labelled neurons could be identified as either widefield (44.6%) or narrowfield (18.9%) vertical cells. These results, when considered together with those from the normal adult and neonatally enucleated adult hamsters, support the conclusion that neonatal eye removal results in a reorganization of the dendritic arbors of some collicular neurons that have already undergone considerable development at the time of the lesion.
Substance P innervation of the rat and cat thalamus. I. Distribution and relation to ascending spinal pathways
Authors: Battaglia Giorgio , Spreafico Roberto , Rustioni Aldo 
Published: January 2005

AbstractAn antiserum for substance P (SP) with minimal cross‐reactivity for other tachykinins was employed to map the distribution of SP‐positive nerve fibers and terminals in the thalamus of cats and rats with special emphasis on the innervation by these fibers of nuclei related to the somatosensory system. In both species SP innervation is predominantly along the midline, in medial and posterior thalamic regions, and sparser in sensory relays for specific modalities. Among the most densely innervated nuclei are the parafascicular, paraventricular, rhomboid, central medial and parts of mediodorsal, lateral posterior, and ventral lateral geniculate. SP innervation of somatosensory‐related nuclei is also evident in central lateral nucleus, posterior complex (PO), and in ventroposterolateral (VPL) nucleus of both cats and rats. In VPL of cats SP fibers and terminals are present along its ventral and lateral border, a paralaminar area in which spinothalamic fibers have been shown to terminate and where neurons responsive to noxious stimuli have been reported. Also in rats the SP innervation of VPL is similar to that of spinothalamic tract fibers. The SP innervation of somatosensory thalamic nuclei may be supplied, at least in part, by spinothalamic afferent as suggested by the depletion of SP after anterolateral chordotomy but not after ablation of the dorsal column nuclei. The presence of SP‐positive spinothalamic neurons in the spinal cord is reported in the following paper.
Premotor descending neurons responding selectively to local visual stimuli in flies
Authors: Gronenberg Wulfila , Strausfeld Nicholas J. 
Published: January 2005

AbstractThe responses of dorsal descending neurons suggest great versatility of the visual system in detecting features of the visual world. Although wide‐field motion‐sensitive neurons respond to symmetric visual flow fields presented to both eyes, other neurons are known to respond selectively to asymmetric movement of the visual surround. The present account distinguishes yet a third class of descending neurons (DNs) that is selectively activated by local presentation of moving gratings or small contrasting objects. Excitation of these DNs in response to local motion contrasts with their inhibitory responses to wide‐field motion. The described DNs invade dorsal neuropil of the pro‐ and mesothoracic ganglia where they converge with other morphologically and physiologically characterized descending elements. Axon collaterals of DNs visit thoracic neuropil containing the dendrites of motor neurons supplying indirect neck and flight muscles. The present results are discussed with respect to the organization of small‐field retinotopic outputs from the lobula, and with respect to the parallel projection of many information channels from the brain to the neck and flight motors.
Trigeminocerebellar projections to the posterior lobe in the cat, as studied by anterograde transport of wheat germ agglutinin‐horseradish peroxidase
Authors: Ikeda Michiko , Matsushita Matsuo 
Published: January 2005

AbstractCerebellar projections of the nucleus interpolaris and oralis of the spinal trigeminal nucleus were studied in the cat by anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP). Injections of WGA‐HRP into these nuclei labeled many mossy fiber terminals mainly ipsilaterally in the rostral folium of lobule IX (IXa or IXa + b), the simple lobule, the anterior part (sublobule A) of the paramedian lobule and the posterior part of crus II. Labeled terminals were also seen in the anterior lobe, lobules VI and VII, the anterior part of crus I, and the paraflocculus dorsalis.Projection fields in the horizontal plane of lobules were reconstructed from a series of transverse sections through each folium of lobule IX, the paramedian lobule, and the posterior part of crus II on the ipsilateral side. In sublobule IXa + b, labeled terminals were distributed in five longitudinal areas extending along the apicobasal axis of the sublobule. These five areas were located in the apical two‐thirds of the ipsilateral half of the sublobule. Labeled terminals were distributed in five longitudinal areas in sublobule A (the rostral part) of the paramedian lobule. In the posterior part of crus II, four aggregations of labeled terminals were present in cross sections through a lobule. They were distributed in the apicobasal extent of the lobules.The present study indicates that the projection fields of trigeminocerebellar fibers are longitudinally arranged along the apicobasal axis of the cerebellar lobules.
Prenatal development of neurons in the human prefrontal cortex. II. A quantitative Golgi study
Authors: Mrzljak Ladislav , Uylings Harry B. M. , Kostovic Ivica , van Eden Corbert G. 
Published: January 2005

AbstractThe quantitative development of neurons in the human dorsolateral and lateral prefrontal cortex was studied in Golgi‐impregnated tissue from postmortem brains ranging from 13.5 weeks of gestation up to the second postnatal month. Pyramidal neurons in the future layers III and V of the cortical plate, as well as different types of neurons in the transient subplate zone, were studied. The basal dendrites of the future layer III and V pyramidal neurons show a slow increase during the first two‐thirds of the period of gestation. From 27–32 weeks of gestation on, there is a rapid increase in the length of basal dendrites of layer III and V pyramidal neurons, while the number of basal dendrites per pyramidal neuron appears to stabilize at 26/27 weeks of gestation. The increase in total length of basal dendrites per pyramidal neuron is mainly due to an increase in the number of bifurcations and the growth of terminal segments. Throughout the whole period studied, the size of the layer III pyramidal basal dendritic tree was smaller than that of layer V pyramidal neurons. Thus, not until postnatal life do the layer III pyramidal basal dendrites become larger than those of layer V. No statistically significant differences were found for data of the pyramidal neurons between the superior and middle frontal gyri. The dendritic size of subplate neurons, except for the subplate inverted pyramidal neurons, significantly exceeds the size of the basal dendrites of the pyramidal neurons up to the seventh gestational month, which indicates an earlier maturation of these subplate neurons. During the period examined, no clear decrease in the size of the subplate neurons was observed. The present study shows that the dendritic parameters of either subplate or cortical plate pyramidal neurons rapidly increase during the periods of ingrowth of afferent fibers into the subplate zone and cortical plate, respectively. In the Golgi preparations of the prefrontal cortex, the size of the subplate neurons does not show any clearly regressive changes at the end of the prenatal period.
Transmitter diversity in ganglion cells of the guinea pig gallbladder: An immunohistochemical study
Authors: Talmage Erin K. , Pouliot Wendy A. , Cornbrooks Ellen B. , Mawe Gary M. 
Published: January 2005

AbstractSeveral neurotransmitters have been reported to exist in the ganglionated plexus of the guinea pig gallbladder. These include substance P, neuropeptide Y (NPY), calcitonin gene‐related peptide, vasoactive intestinal peptide (VIP), acetylcholine, norepinephrine, serotonin and dopamine. To determine which neuropeptides are intrinsic to gallbladder ganglia, we performed immunohistochemistry on colchicine‐treated preparations. In separate, single‐labeled preparations, a majority of neurons contained substance P‐, NPY‐, or somatostatin‐like immunoreactivity. In double‐labeled preparations, a large majority of the neurons that contained substance P‐like immunoreactivity also contained NPY‐like immunoreactivity and somatostatin‐like immunoreactivity. Immunoreactivity for VIP was present in a small percentage of the gallbladder neurons which did not contain substance P‐like immunoreactivity. Additional experiments were done to test for the presence of other compounds, known to exist in the neurons of the gut. Although immunoreactivity was found in control preparations of small intestine, the ganglionated plexus of the gallbladder lacked immunoreactivity for galanin, dynorphin, enkephalin, gastrin‐releasing peptide, or gamma‐aminobutyric acid. We conclude that ganglia of the guinea pig gallbladder contain at least two populations of neurons, based on transmitter phenotype. One of these populations appears to contain substance P, NPY, and somatostatin. Another population, which represents a small contingent of the total population of neurons, contains VIP.
Morphological and neurochemical features of cultured primary skin fibroblasts of fischer 344 rats following striatal implantation
Authors: Kawaja Michael D. , Gage Fred H. 
Published: January 2005

AbstractIn order to assess the feasibility of using primary skin fibroblasts as a donor population for genetic modification and subsequent intracerebral grafting, the present study examines the structural and neurochemical characteristics of intrastriatal grafts of isogeneic primary fibroblasts over a period of 6 months. In culture, primary skin fibroblasts obtained from a female Fischer 344 rat display robust growth, but once confluent these cells exhibit contact inhibition. Following the implantation of cultured primary cells within the striatum of other adult rats from the same inbred strain, isologous grafts stain immunohistochemically for fibronectin at 1 week, and this immunostaining persists up to 6 months. Immunoreactivity for laminin is intense within the grafts from 1 to 8 weeks, but decreases by 6 months. Astrocytes within the striatum respond dramatically to the implantation of primary fibroblasts, such that immunohistochemical staining for glial fibrillary acidic protein increases markedly from 1 to 8 weeks after implantation. Although the intensity of immunostaining for glial fibrillary acidic protein diminishes among striatal astrocytes between 8 weeks and 6 months, the astrocytic border between the grafts and striatal neuropil remains intensely immunoreactive. Capillaries within the grafts stain immunohistochemically for glucose transporter (a facilitated glucose uptake carrier) as early as 3 weeks after implantation. Following intravenous infusions of peroxidase, capillaries within fibroblast grafts do not permit the extravasation of this macromolecule at 8 weeks and 6 months. Thus, capillaries formed within intracerebral grafts of primary skin fibroblasts exhibit a functional impermeable barrier to macromolecules similar to those capillaries of the host striatum. At the ultrastructural level, grafts possess numerous fibroblasts and have an extracellular matrix filled with collagen. Reactive astrocytic processes filled with intermediate filaments are found throughout the grafts. Hypertrophied astrocytes and their processes also appear to form a continuous border between the grafts and striatal neuropil. Grafts of primary fibroblasts also possess an extensive vasculature that is composed of capillaries with nonfenestrated endothelial cells; the occurrence of reactive astrocytic processes closely associated with or enveloping capillaries is variable. These results provide direct morphological and neurochemical evidence for the long‐term survival of isologous fibroblasts after implantation within the rat striatum. From these data, we propose that isologous skin fibroblasts can be considered as donor candidates for successful intracerebral grafting following gene transfer.
Visual factors in sound localization in mammals
Authors: Heffner Rickye S. , Heffner Henry E. 
Published: January 2005

AbstractThe ability of mammals to localize sound varies widely among species. During the past decade, evidence has accumulated that this variation cannot be accounted for simply on the basis of the availability of the physical cues for locus. Evidence is presented that a major factor in sound localization is the need to direct the field of best vision to a sound source for further scrutiny. Thus, species with broad fields of best vision (such as visual streaks) require less accurate information regarding the location of a sound source than do species with very narrow fields of best vision (such as foveae). To support this suggestion, data are reported for the width of the field of best vision in the form of retinal ganglion cell isodensity contours for thirteen species of mammals. The possible contribution of other factors including binocular fields, visual acuity, and the degree to which a species is predatory in lifestyle, is also examined.
Organizational and morphological features of cat sacrocaudal motoneurons
Authors: Ritz Louis A. , Bailey Steven M. , Murray Constance R. , Sparkes Mary L. 
Published: January 2005

AbstractWe have investigated the organizational and morphological features of motoneurons from cat sacrocaudal spinal cord, the portion of the neuraxis that innervates the tail. This information is pertinent for development of a new model of spinal cord injury. An understanding of sacrocaudal circuitry is essential for physiological and behavioral assessment of the effects of sacrocaudal lesions.Observations from Nissl‐stained sections corroborated Rexed's cytoarchitectural scheme. Putative motoneurons were located within two regions of the ventral horn: the ventromedial nucleus (lamina IX) and the nucleus commissuralis. To map motoneuron pools, choleratoxin‐horseradish peroxidase conjugate was injected into each dorsal tail muscle. The dorsomedial muscle was innervated by ipsilateral nucleus commissuralis motoneurons. The dorsolateral and intertransversarius muscles were innervated by ipsilateral lamina IX and nucleus commissuralis motoneurons. Cell bodies of retrogradely labeled sacrocaudal motoneurons ranged from 22 to 82 μm in diameter; the unimodal distributions peaked between 45 and 50 μm.Dendritic trees of motoneurons, revealed by retrograde labeling or by intracellular injection with horseradish peroxidase, were extensive. Five to eight primary dendrites originated from the cell body. Dendritic branches extended throughout the ipsilateral ventral gray matter, with processes spreading into the surrounding white matter and the base of the dorsal horn. Dendrites from motoneurons with their soma in the lateral portion of lamina IX formed a longitudinal plexus at the gray/white border. Medial dendrites from motoneurons in the nucleus commissuralis formed bundles in the ventral gray commissure and spread throughout the contralateral ventral horn. It is speculated that contralateral dendrites subserve synchronized co‐contraction of medial muscles from both sides of the tail.
Regional distribution of DARPP‐32 (Dopamine‐ 0Mr = 32,000) mRNA in mouse brain
Authors: Perez Ruth G. , Lewis Robert M. 
Published: January 2005

AbstractDARPP‐32 (dopamine‐ and adenosine 3′,5′‐mbnophosphate‐regulated phosphoprotein of Mr = 32,000) mRNA distribution was examined in adult mouse central nervous system by in situ hybridization. In general, DARPP‐32 mRNA was found in regions of brain where cells express the dopamine D1 subtype receptor. Cells of the olfactory tubercle, caudate‐putamen, and nucleus accumbens had the highest levels of DARPP‐32 mRNA, as did choroid plexus and Purkinje cells. Relatively high levels were found in medial habenula and lateral piriform cortex. Moderate levels were seen in cerebral cortex layer VI, medial piriform cortex, lateral entorhinal cortex, tenia tecta, anterior olfactory nucleus, and lateral bed nucleus of the stria terminalis. Low levels were observed in hippocampus, cerebral cortex layers II and III, olfactory bulb, and the nucleus of the lateral olfactory tract. DARPP‐32 mRNA levels in the amygdaloid nuclei varied greatly.
The nigral projection to predorsal bundle cells in the superior colliculus of the rat
Authors: Bickford M. E. , Hall W. C. 
Published: January 2005

AbstractPredorsal bundle cells give rise to the major efferent pathway from the superior colliculus to the premotor centers of the brainstem and spinal cord responsible for initiating orienting movements. The activity of predorsal bundle cells is profoundly influenced by an inhibitory pathway from substantia nigra pars reticulata that uses gamma aminobutyric acid (GABA) as a neurotransmitter. The present study examines the morphological basis for this influence of substantia nigra on predorsal bundle cells in the rat. In the first experiments, the laminar distributions of the nigrotectal tract terminals and the predorsal bundle cells were compared. The predorsal bundle cells were labeled by the retrograde axonal transport of horseradish peroxidase from either the decussation of the predorsal bundle or the cervical spinal cord, while the terminations of the pathway from substantia nigra pars reticulata were labeled by anterograde axonal transport from the substantia nigra. Either horseradish peroxidase, wheat germ agglutinin conjugated to horseradish peroxidase, or Phaseolus vulgaris leucoagglutinin were used as anterograde tracers. The results showed that the distributions of both the predorsal bundle cells and the nigrotectal terminals are restricted almost entirely to the intermediate grey layer and that they overlap extensively. Predorsal bundle cells varied in size. Within the areas of maximum overlap, the majority, regardless of size, was closely apposed by nigrotectal terminals. In a second series of experiments, the synaptic contacts between nigrotectal terminals and the tectospinal component of the predorsal bundle were examined in tissue in which both the terminals and the tectospinal cells were labeled for electron microscopy. In the final experiments, the distribution and fine structure of the nigrotectal terminals were compared to those of terminals that had been labeled immunocytochemically with an antibody to glutamic acid decarboxylase, the synthesizing enzyme for GABA. The results showed that nigrotectal terminals contain large numbers of mitochondria and pleomorphic vesicles, and form synaptic contacts with the somas and proximal dendrites of tectospinal cells. These synapses have modest postsynaptic densities. In both their distribution and fine structure, these terminations resemble the glutamic acid decarboxylase immunoreactive terminals that contact tectospinal cells. Taken together, these results support the view that the nigrotectal tract is an important source of GABAergic input to most, if not all, predorsal bundle cells. © 1992 Wiley‐Liss, Inc.