bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology of identified preganglionic neurons in the dorsal motor nucleus of the vagus
Authors: Fox Edward A. , Powley Terry L. 
Published: January 2005

AbstractTo determine the degree of variation of neuronal morphology both within and between the subnuclei of the dorsal motor nucleus of the vagus (dmnX), structural features of the preganglionic neurons of each of the five primary subnuclei in the rat dmnX were characterized quantitatively. Each of the columnar subnuclei was separately labeled by application of the retrograde tracer fast blue to its corresponding subdiaphragmatic vagal branch. Fixed brain slices of 100 μm thickness were then prepared in coronal, sagittal, and horizontal orientations. Next, randomly selected fast blue labeled neurons (n = 1,256) were injected with Lucifer yellow, drawn with camera lucida, and digitized. For each cell, three features of the perikaryon and twelve of the dendritic tree were measured.Dorsal motor nucleus neurons with up to eight primary dendrites, 30 dendritic segments, and seventh order dendritic branches were observed. Throughout the dmnX, the dendrites of preganglionic neurons were preferentially oriented in the horizontal plane. Consistent with an organizing role for the columnar subnuclei, most dendrites remained within their column of origin. However, between 5 and 30% of the neurons in each of the columns projected dendrites into adjacent dmnX subnuclei or other brainstem nuclei, including the nucleus of the solitary tract (NTS). The cyto‐ and dendroarchitectural analyses revealed systematic gradations in morphology, although they did not support the idea that the dmnX was composed of multiple distinct preganglionic types. The most parsimonious interpretation of the data is that dmnX motorneurons are variants of a single prototype, with dendrites varying widely in length and degree of ramification. The extent of an individual preganglionic neuron's dendritic field was predicted by three factors: the cell's rostrocaudal position within the dmnX, its location within a transverse plane (i.e., its coronal position within or ectopic to the dmnX), and its subnucleus of origin. Neurons at rostral and midlongitudinal levels of each column had more extensive dendritic arbors than those at caudal levels. Ectopic neurons had more extensive dendritic fields than similar cells in the corresponding columns; in fact, of all vagal preganglionic neurons, ectopics had the most extensive dendritic fields. Somata and dendrites of celiac column neurons were more extensive than those of hepatic and gastric column cells. These differential regional distributions of vagal preganglionics suggest that their structure and function are correlated. © 1992 Wiley‐Liss, Inc.
Functional degeneration of isolated central stumps of crayfish sensory axons
Authors: Govind C. K. , Blundon J. A. , Kirk M. D. 
Published: January 2005

AbstractIn the crayfish, Procambarus clarkii, nerve 5 carries primarily sensory axons from the tail fan to the 6th abdominal ganglion where they synaptically activate interneuron A. Since the sensory neurons have their somata located at the periphery, transection of nerve 5 part way to the ganglion allowed us to examine the fate of their soma‐less central stumps. Up to 3 weeks postlesion the response to stimulation of nerve 5 consisted of a brief latency spike in interneuron A, similar to that in control animals and to stimulation of the intact nerve 4. Stimulation of the lesioned nerve 5 beyond 3 weeks failed to fire interneuron A. This loss of function was correlated to loss of axons in nerve 5 deduced by comparing the numbers in the lesioned nerve 5 to its contralateral intact counterpart. The numbers are about equal in the paired nerves but rapidly decline on the lesioned side to 50% within 1 week, 20% within 3 weeks, and less than 10% in subsequent weeks. This loss affects all size classes of axons. However, in the 3 week lesioned nerve large glial infoldings subdivided some of the larger axons and single nuclei were seen in a few of the medium‐sized axons, Possibly subdivision of large axons by glial infolding may introduce glial nuclei into axons. © 1992 Wiley‐Liss, Inc.
Cortical and striatal structure and connectivity are altered by neonatal hemidecortication in rats
Authors: Kolb Bryan , Gibb Robbin , van der Kooy Derek 
Published: January 2005

AbstractThe cortical cytoarchitecture, cortical thickness, corticostriatal connections, cortical dendritic arborization, and striatal patch‐matrix compartmentalization were compared in rats with neonatal (1 day of age) or adult hemidecortication. Neonatal hemidecortication produced few changes in cytoarchitecture of the remaining hemisphere and did not preclude the development of a patch‐matrix compartmentalization in either striatum. There was a significant modification of contralateral cortical‐striatal connections, however, as there were extensive crossed connections from layer II/III of the prefrontal cortex in the neonatal hemidecorticates, which contrasts with connections from layer V in the normal brain. Adult hemidecorticates had no crossed corticostriatal connections. Neonatal hemidecortication also led to an increase in cortical thickness relative to adult operates or controls and the neonatal hemidecorticates, and led to an increase in dendritic arborization in layer II/III pyramidal cells of the somatosensory and motor cortex but not in the visual or temporal cortex. The results suggest that the behavioral sparing of sensorimotor and some prefrontal functions after neonatal hemidecortication could be supported, in part, by the anatomical changes in the prefrontal and sensorimotor connectivity and dendritic arborization. © 1992 Wiley‐Liss, Inc.
Relationships between dendritic morphology and cytochrome oxidase compartments in monkey striate cortex
Authors: Hübener Mark , Bolz Jürgen 
Published: January 2005

AbstractIn primate striate cortex, staining for the mitochondrial enzyme cytochrome oxidase reveals a regular pattern of intense staining, the blobs, which are surrounded by the lighter stained interblob regions. Neurons in both compartments exhibit profound functional differences: blob cells have color selective, unoriented receptive fields, whereas interblob cells are usually not color selective and have oriented receptive fields, Neuroanatomical tracing studies have shown that blob and interblob cells receive different inputs and participate in different projections. It is not known, however, whether this compartmental organization is also reflected in the dendritic morphology of individual cells. We therefore combined intracellular staining with cytochrome oxidase histochemistry to study the relationship between cell morphology and blob pattern in layers 2 and 3 of macaque striate cortex. Single cells were injected with the fluorescent dye lucifer yellow in lightly fixed tangential sections. Adjacent sections were reacted for cytochrome oxidase to reveal the blobs. The spatial relationship between stained cells and the pattern of the blobs were subsequently determined by aligning the sections by using radially running blood vessels as landmarks.Our results show that pyramidal cells located in blob and interblob regions do not differ in their soma size, spine density, and basal dendritic field structure. This indicates that the characteristic functional properties of the neurons in both compartments do not depend on the morphology of their dendritic trees. Since the elongation of the dendritic fields of blob and interblob cells was also found to be similar, we conclude that cortical orientation selectivity is not generated through elongated dendritic fields.We found several cells with dendrites freely crossing the borders between blob and interblob regions. These cells might correspond to cells with “mixed” receptive field properties, e.g., color selective oriented cells, which in physiological studies were found at the transition from blob to interblob regions. However, there were also a number of cells that respected the borders. A quantitative analysis of the dendritic fields revealed that 67% of the cells located close to the borders have a tendency to confine their dendrites to only one compartment. Thus the pattern of basal dendrites of these cells might be shaped by the parcellation of the striate cortex in blob and interblob regions. These dendritic field asymmetries may help to maintain the segregation at the single cell level into different processing channels in monkey striate cortex.
Sexual dimorphism in the vasotocin system of the bullfrog (Rana catesbeiana)
Authors: Boyd Sunny K. , Tyler Chris J. , de Vries Geert J. 
Published: January 2005

AbstractArginine vasotocin (AVT) is widespread in amphibian brains, where its levels have been correlated with reproductive behaviors. To better understand which neural systems are involved in central actions of AVT, we used immunocytochemistry to compare the distribution of AVT in the brains of male and female bullfrogs (Rana catesbeiana). AVT‐immunoreactive cells were observed in the septal nucleus, amygdala pars lateralis, magnocellular preoptic area, suprachiasmatic nucleus, and hypothalamus. AVT‐immunoreactive cells were also found in the pretrigeminal nucleus, but only in animals killed in the fall. Immunoreactive fibers were broadly distributed in hypothalamic and extrahypothalamic areas. The most obvious sex differences were found in the amygdala pars lateralis, where the density of immunoreactive cells and fibers was significantly greater in male than in female bullfrogs. In addition, in the habenular nucleus, males had a denser distribution of AVT‐immunoreactive fibers than females. In the suprachiasmatic nucleus, AVT‐immunoreactive cells were larger in females than in males but did not differ in number. Since the areas that showed sex differences in AVT distribution have also been implicated in control of reproductive behaviors, they may form the neural substrates for the effects of AVT on sexually dimorphic behaviors in amphibians. © 1992 Wiley‐Liss, Inc.
Noradrenergic modulation of noxious heat‐evoked fos‐like immunoreactivity in the dorsal horn of the rat sacral spinal cord
Authors: Jones S. L. 
Published: January 2005

AbstractThis tail‐flick withdrawal reflex commonly is used to study spinal nociceptive mechanisms; noradrenergic agonists administered intrathecally inhibit the tail‐flick‐ reflex in a dose‐dependent manner. The objectives of the present study, were: (1) to use fos‐like immunoreactivity as a marker for neuronal activity to examine the population of neurons in the spinal cord dorsal horn that are engaged by activation of nociceptive tail afferents, and (2) to determine whether fos‐like immunoreactivity can be modulated by intrathecally administered alpha adrenoceptor agonists.Neurons demonstrating heat‐evoked fos‐like immunoreactivity were identified bilaterally in the sacral spinal cord in superficial and deep dorsal horn laminae. Heat‐evoked fos‐like immunoreactivity was inhibited dose‐dependently by intrathecal norepinephrine (NE). The inhibition was attenuated significantly by: (1) phentolamine (PHEN), a nonselective alpha adrenoceptor antagonist; (2) yohimbine (YOH), an alpha‐2 adrenoceptor antagonist; and (3) prazosin (PRAZ), an alpha‐1 adrenoceptor antagonist. Thus, both spinal alpha‐1 and alpha‐2 adrenoceptors mediate the inhibition of heat‐evoked fos‐like immunoreactivity produced by intrathecal NE. ST‐91, an alpha‐2 adrenoceptor agonist, also inhibited significantly the expression of fos‐like immunoreactivity; the inhibition was antagonized by YOH.In the absence of noxious heat, intrathecal NE dose‐dependently evoked the expression of fos‐like immunoreactivity in the superficial dorsal horn, which was antagonized by PHEN and PRAZ, but not by YOH, suggesting that the effect is mediated by spinal alpha‐1 adrenoceptors. © 1992 Wiley‐Liss, Inc.
Analysis of low affinity nerve growth factor receptor during pulpal healing and regeneration of myelinated and unmyelinated axons in replanted teeth
Authors: Byers Margaret R. , Kvinnsland Inger , Bothwell Mark 
Published: January 2005

AbstractNerve regeneration was examined in rat molars that were briefly extracted and then replanted in the socket for 1–90 days. Immunocytochemistry was used to evaluate neural and nonneural immunoreactivity (IR) for low affinity nerve growth factor receptor (p75‐NGFR) and for laminin and calcitonin gene‐related peptide (CGRP). Three different types of pulpal response to replantation were found. Type I: Some replanted teeth had mild injury and still contined coronal odontoblasts and associated fibroblasts that retained p75‐NGFR‐IR; they continued regular dentin formation and had excellent reinnervation. Type II: Teeth with intermediate injury lost most or all of the coronal pulp tissue, but they regenerated odontoblast‐like cells that formed irregular dentin, they had numerous dispersed p75‐NGFR‐IR fibroblasts in crown pulp during early regeneration, and they had excellent reinnervation. Type III: Severely injured teeth lost their original pulp; they filled with dense connective tissue and bone and had poor reinnervation. After Type I or II injury the Schwann cells around degenerating myelinated and unmyelinated axons had increased expression of p75‐NGFR by 1–3 days. By 7–10 days those Schwann cells had formed hollow tubes (bands of Bungner) along the degenerating axon tracks. They maintained their increased p75‐NGFR‐IR during and after regeneration of unmyelinated axons, whereas Schwann cells involved in remyelination lost p75‐NGFR‐IR at that stage. The number of CGRP‐IR axons in the regenerating pulp increased from 7 to 90 days. Laminin‐IR increased in all replanted teeth at 3–10 days and only returned to normal patterns in teeth with Type I or Type II response at 20–90 days. The special p75‐NGFR‐IR of pulpal fibroblasts of adult rat molars did not usually persist in regenerated, reinnervated pulp. The extensive depletion of fibroblast p75‐NGFR‐IR and the continuing enhanced p75‐NGFR‐IR in unmyelinated nerve fibers at 90 days show that altered growth factor conditions characterize regenerated pulp of replanted teeth. © 1982 Wiley‐Liss, Inc. © 1992 Wiley‐Liss, Inc.
Immunocytochemical study of somatostatin, neurotensin, GABA, and glycine in rat spinal dorsal horn
Authors: Proudlock F. , Spike R. C. , Todd A. J. 
Published: January 2005

AbstractIn order to determine whether somatostatin coexists with GABA or glycine in neurones in rat spinal dorsal horn, a combined pre‐ and post‐embedding immunocytochemical study was carried out. One hundred six somatostatin‐immunoreactive neurones located in lamina II and the dorsal half of lamina III were tested with antiserum or monoclonal antibody to GABA and none of these cells showed GABA‐like immunoreactivity. However, 8 out of 13 somatostatin immunoreactive neurones located deeper in the dorsal horn (ventral lamina III and lamina IV) showed glycine‐like immunoreactivity, and 6 of these were also GABA‐immunoreactive. We have previously shown that neurotensin‐immunoreactive neurones in laminae II and III are also not immunoreactive when tested with GABA antiserum (Todd et al.: Neuroscience 47: 685–691, 1992), and a double‐labelling fluorescence method was therefore used to compare the distribution of somatostatin and neurotensin within the superficial dorsal horn. The two types of peptide‐immunoreactivity were never found in the same profile.These results suggest that somatostatin and neurotensin are present in different populations of non‐GABAergic neurones in rat superficial dorsal horn, but that some somatostatin containing neurones in the deeper part of the dorsal horn contain glycine, with or without GABA. © 1993 Wiley‐Liss, Inc.
Network of GABAergic large basket cells in cat visual cortex (area 18): Implication for lateral disinhibition
Authors: Kisvárday Zoltán F. , Beaulieu Clermont , Eysel Ulf T. 
Published: January 2005

AbstractAnatomical and immunohistochemical data indicate that, in addition to pyramidal neurons, nonpyramidal cells are exposed to perisomatic inhibition mediated by γ‐aminobutyric acid (GABA)‐containing terminals. However, no direct information is available as yet for the origin of GABAergic inputs to morphologically identified GABAergic neurons. In the present paper, we studied the topographical and synaptic relationship between identified GABAergic large basket cells and their immunohistochemically characterized target neurons revealed by parvalbumin‐(PV) and GABA immunostaining in the same material.Extracellularly applied biocytin labelled a total of 36 and 9 large basket cells in layers III and V, respectively. Of these, the axonal arborizations of two basket cells, BC1 and BC2, were reconstructed. The axon of BC1 occupied an area of about 2.3 × 2.2 mm2 in layer III, providing a total of 2,755 terminals. The axon of BC2 showed an overall extent of 3.8 × 1.7 mm2 in layer V elongated in the anteroposterior direction, and gave off 1,599 terminals. Immunostaining for PV was carried out to reveal putative nonpyramidal targets for BC1 and BC2. It was found that in addition to immunonegative cells, they established an average of 4–6 perisomatic contacts onto each of 58 (BC1) and 33 (BC2) PV‐immunopositive neurons. For electron microscopic verification, 23 terminals apposing the somata of 12 PV‐immunopositive neurons were selected. Each terminal was found to establish symmetrical (type II) contacts with its targeted cell. Furthermore, the distribution of soma area of the targeted PV‐immunopositive cells and of identified large basket cells showed remarkable similarity, implying that the two populations were actually the same. In addition, the average horizontal distance between neighbouring PV‐immunopositive target cells was found to be about 100 μm both in layers III and V.The results suggest that in area 18 the same large basket cell provides direct inhibition to certain pyramidal cells and facilitation to other pyramidal neurons, by inhibiting their presynaptic large basket cells at regular intervals. 1993 Wiley‐Liss, Inc.
Functional and anatomical organization of cardiovascular pressor and depressor sites in the lateral hypothalamic area. II. Ascending projections
Authors: Allen Gary V. , Cechetto David F. 
Published: January 2005

AbstractMicroinjections of L‐glutamate or D, L‐homocysteic acid were used to stimulate cell bodies in the region of the lateral hypothalamic area (LHA) selectively. Subsequent iontophoretic injections ofPhaseolus vulgaris‐leucoagglutinin or pressure injections of wheat germ agglutininhorseradish peroxidase were made into regions containing identified pressor and depressor sites and their connections with the forebrain and cerebral cortex were traced.The results indicate that decreases in blood pressure (10–45 mm Hg) and heart rate (20–70 bpm) could be elicited from tuberal (LHAt) and posterior (LHAp) sites in the LHA and that these regions have ascending projections to the insular cortex, the ventral forebrain including the septal‐diagonal band of Broca complex, the ventral palladium, substantia innominata, amygdala, and the lateral preoptic area. In contrast, increases in blood pressure (10–40 mm Hg) and heart rate (20–70 bpm) were elicited primarily from neurons located adjacent to the fornix in the perifornical area (PFA). Injections of tract tracers into this region produced terminal labeling that differed markedly from the pattern seen following injections of tracer into depressor sites in the LHA. In addition, the pattern of anterograde labeling seen following injections of tracer into the anterior PFA differed from that seen following injections of tracer into posterior PFA. Injections of tracer into the anterior PFA resulted in dense terminal labeling in the medial preoptic area and the parvicellular paraventricular nucleus of the hypothalamus whereas injections into the posterior PFA resulted in dense terminal labeling in the lateral septal nucleus, nucleus accumbens, bed nucleus of the stria terminalis, as well as the medial preoptic area and the parvocellular paraventricular nucleus of the hypothalamus.The results demonstrate that the posterolateral hypothalamus of the rat contains two regions with specific cardiovascular function and highly organized connections with diencephalic, forebrain, and cortical structures.
Efferent projections from the anterior thalamic nuclei to the cingulate cortex in the rat
Authors: Shibata Hideshi 
Published: January 2005

AbstractThe organization of projections from the anterior thalamic nuclei to the cingulate cortex was analyzed in the rat by the anterograde transport of Phaseolus vulgaris‐leucoagglutinin.The rostral part of the anteromedial nucleus projects to layers I, V and VI of the anterior cingulate areas 1 and 2, layers I and III of the ventral orbital area, layers I, V and VI of area 29D of the retrosplenial area, and layers I and V of the caudal part of the retrosplenial granular and agranular areas. In contrast, the caudal part of the anteromedial nucleus projects to layer V of the frontal area 2, and layers I and V of the rostral part of the retrosplenial granular and agranular areas. The interanteromedial nucleus projects to layers I, III and V of the frontal area 2, layer V of the agranular insular area, and layers I, V and VI of area 29D. The anteroventral nucleus projects to layers I and IV of the retrosplenial granular area, whereas the anterodorsal nucleus projects to layers I, III and IV of the same area. Projections from the anteroventral and anterodorsal nuclei were, furthermore, organized such that their ventral parts project to the rostral part of the retrosplenial granular area, whereas their dorsal parts project to the more caudal part.The results suggest that the anterior thalamic nuclei project to more widespread areas and laminae of the cingulate cortex than was previously assumed. The projections are organized such that the anteromedial and interanteromedial nuclei project to layer I and the deep layers of the anterior cingulate and retrosplenial cortex, whereas the anteroventral and anterodorsal nuclei project to the superficial layers of the retrosplenial cortex. These thalamocortical projections may play important roles in behavioral learning such as discriminative avoidance behavior.