摘要:

AbstractThe distribution of Phe‐Leu‐Arg‐Phe (FLRF)‐like immunoreactivity is described in the brain and in the ganglia of the ventral nerve cord of the locustSchistocerca gregaria. A single homologous pair of immunoreactive cell bodies occurs ventrally and medially in the suboesophageal ganglion. Each cell sends a process dorsally which bifurcates into anteriorly and posteriorly running neurites. The single anterior neurite passes along the circumoesophageal connectives to the brain where it ascends in a posterior running tract, giving off branches to innervate the tritocerebral neuropile and ending in an extensive network of highly varicose immunoreactive processes in the protocerebral neuropile. No processes are seen in the optic lobes or associated with the structured neuropiles of the mushroom bodies. The single posterior neurite from each cell passes into the suboesophageal‐prothoracic connectives. It runs in the lateral dorsal tract of each ganglion in the ventral nerve cord as a highly varicose process and in each ganglion gives rise to an ipsilateral network of varicose processes in the dorsal and lateral neuropiles. In the seventh and terminal abdominal ganglia the innervation pattern exhibits sexual dimorphism. Vasopressin‐like immunoreactivity is co‐localized in the same pair of suboesophageal neurones and their processes.A similar pair of ventral median neurones stains with both antibodies in the suboesophageal ganglion of another species of locust,Locusta migratoria. Although the basic distribution pattern of immunoreactive processes is similar in both species there are also marked species differences i

ISSN:0092-7317    

DOI:10.1002/cne.902920302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractInjections of WGA‐HRP were made in the rat C4–C8 dorsal root ganglia (DRGs) individually to study the central projections and their relations to each other. The main dorsal horn projections from these DRGs to the dorsal horn lamina II extended for about two segments rostrally and caudally to the injected DRG, whereas the projections to laminae I, III, and IV were less restricted rostrocaudally. Comparisons of the dorsal horn projections from the DRGs investigated indicated a tendency for a somatotopic organization, which was most prominent in lamina II. Labeled central branches from the C4–8 DRGs could be traced in the dorsal column as far caudally as 12‐17 segments caudal to the level of entrance. Most of these fibers appeared to end in the medial dorsal horn base, including the column of Clarke. Labeling of primary afferents in the ventral horn generally extended for at least 3‐4 segments rostral and caudal to the level of the injected DRG. Projections to the central cervical nucleus were most prominent from the C4 DRG and gradually became less prominent from the more caudal DRGs. Heavy projections to the cuneate nucleus (Cun) originated from the C7 and C8 DRG, whereas those from the C4–C6 DRGs were less extensive. The Cun projections from the different DRGs appeared to overlap, and the same was true for the projections to the external cuneate nucleus. Projections to the gracile nucleus, the vestibular nuclear complex, including nucleus X, and to trigeminal sensory nuclei were seen from all DRGs i

ISSN:0092-7317    

DOI:10.1002/cne.902920303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe extent to which the compartmental and topographical innervation patterns were re‐established in the mature glutaeus muscle after nerve cut was determined by HRP retrograde labelling procedures and single motor unit glycogen depletion experiments. Glutaeus muscle axons normally cluster together along the length of the sciatic nerve and enter the triceps femoris nerve along with axons to the cruralis and tensor fasciae latae muscles. Glutaeus axons did not specifically reinnervate the glutaeus muscle after cutting the triceps femoris nerve. Axons within the glutaeus muscle nerve are grouped according to the primary nerve branch, and therefore muscle compartment, for which they are destined. When the glutaeus nerve was cut, regenerating axons lost their compartmental organization within the glutaeus nerve and nonspecifically reinnervated both glutaeus muscle compartments. In marked contrast, the topographical projection of spinal motoneurones to the ventral and dorsal halves of the glutaeus muscle was largely re‐established after glutaeus nerve cut; that is, rostral motoneurones mostly reinnervated ventral muscle fibres, whereas caudal motoneurones reinnervated dorsally located muscle fibres. The relatively confined caudal projection was closely related to the sharp fibre type divisions within the glutaeus muscle. The results suggest that factor(s) present during development that determine the correct innervation of a muscle and its compartments no longer operate in the adult, although cues that direct motor terminals to their appropriate muscle region do, and these are most likely related to the topographical distribution of fibre ty

ISSN:0092-7317    

DOI:10.1002/cne.902920304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe ascending projections of the cochlear nucleus (CN) and the sources of descending inputs to the CN were investigated in horseshoe bats (Rhinolophus rouxi) by tracing the anterograde and retrograde transport of horseradish peroxidase (HRP or WGA‐HRP) injected into the CN. The tracer was iontophoretically deposited into physiologically characterized regions of the cochlear nucleus (Feng and Vater, '85). We report the course and termination of pathways arising from the anteroventral (AVCN), posteroventral (PVCN), and dorsal (DCN) cochlear nucleus. The projection fields within the auditory brainstem centers (superior olivary complex [SOC]; lateral lemniscus complex [LLC]; and inferior colliculus [IC]) and their tonotopic organization according to the frequency representations at the injection sites are described. While the projection pattern is generally in accordance with other mammals, several species‐characteristic features are noted: (i) the lateral superior olive (LSO) receives tonotopically organized input from both the AVCN and PVCN; (ii) the CN‐projections to medial nuclear groups of the SOC located between the LSO and the medial nuclear of the trapezoid body do not support previously suggested homologies; (iii) the ventral nucleus of the LLC can be subdivided into two divisions with distinct input patterns from the AVCN and PVCN, respect

ISSN:0092-7317    

DOI:10.1002/cne.902920305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIt has previously been demonstrated that the severed central branches of adult mammalian dorsal root ganglion cells regenerate into transplants of fetal spinal cord. The aim of this study was to determine whether these regenerating axons form synapses, and, if they do, to characterize them morphologically.Embryonic day 14 or 15 spinal cord was transplanted into the limbar enlargement of adult Sprague‐Dawley rats, and the L4 or L5 dorsal root was cut and then juxtaposed to the transplant. One to 3 months later the regenerated dorsal roots were labeled by anterograde filling with wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) or by immunocytochemistry for calcitonin gene‐related peptide (CGRP).Dorsal root labeling with WGA‐HRP demonstrated that regenerated axon terminals made synaptic contacts within transplants, and stereological electron microscopic analysis demonstrated that CGRP‐immunorective axon terminals occupied an average of 9% of the neuropil within 2 mm of the dorsal root‐transplant interface. The majority of synapses were axodendritic, but a significant percentage were axosomatic or axoaxonic. Since axoaxonic synapses were observed in tranplants in which both pre‐ and postsynaptic profiles of axoaxonic synapses were labeled for CGRP, some regenerated axons apparently form synapses with each other. Approximately 90% of synaptic contacts were simple, 9% were complex, and 25% of the complex terminals were immunopositive for CGRP. Glia occupied 25% of the neuropil within 1 mm of the dorsal root‐transplant interface, but only 6% of the neuropil 1–2 mm from the interface.We also performed a stereological analysis of the neuropil in lamina I. The area fractions of neuropil occupied by myelinated axons, perikarya, and dendrites were similar in transplants and in lamina I. However, the area fraction occupied by unmyelinated axons was significantly smaller in transplants, and the area fraction occupied byu axon terminals was significantly larger in transplants compared with lamina I. Regenerated CGRP‐immunoreactive synaptic terminals in transplants were significantly larger than in normal lamina I, and their synaptic contact length was also increased, suggesting that a compensatory mechanism for increasing synaptic efficiency might occur within the transplants. Synaptic density, however, was significantly reduced in transplants, indicating a smaller number of synaptic terminals per unit area. In lamina I, as in the transplant, most synapses were axodendritic, but the percentage of axosomatic and axoaxonic terminals was lower in lamina I than in the transplants. The area occupied by glia in lamina I was similar to that observed 1–2 mm from the dorsal root‐transplant interface, but lower than that observed 0–1 mm from the interface.The results of this study show that regenerated primary afferent axons form synapses within transplants. These synapses retain many of the characteristics of primary afferent synapses in normal dorsal horn, suggesting that transplants may provide a strategy to restore some of the properties

ISSN:0092-7317    

DOI:10.1002/cne.902920306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe distribution of the histaminergic neuronal system in the brain of the clawed frogXenopus laeviswas mapped with an antiserum against carbodiimide‐fixed histamine and compared to that in mammals. The histamine‐immunoreactive cell bodies were located in a small area of the posterolateral hypothalamus, close to the dorsal infundibular nucleus, which contains catecolaminergic and serotonergic neurons. This area may be homologous to the tuberomammillary nucleus in mammals. A thick process extended from each cell between the ependymal cell layer and terminated in the ventricle lumen. The number of histaminergic cell bodies in adultXenopusbrain was relatively low, as compared with the mammalian brain. Preliminary analysis of adjacent sections stained with antisera against GABA or serotonin indicated that the histamine cells were not immunoreactive for these.The pathways and distribution of histaminergic fibers inXenopusbrain showed many similarities to mammals. The densest fiber networks were present in the medial basal forebrain, particularly in the medial amygdala and septum. A distinct cluster of fibers was concentrated around the cell bodies of nucleus accumbens. In most pallial areas, the density was moderate to low. In the primordial piriform cortex and the striatum, very few fibers were seen. In diencephalon, highest fiber densities were found in the anterior and ventral thalamus and posterior and lateral hypothalamus. In hindbrain, the density was highest in the medullary central gray, as in some mammals.The results suggest that the general pattern of the histaminergic system in vertebrate brain is conserved from amphibians to mamm

ISSN:0092-7317    

DOI:10.1002/cne.902920307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractA combination of retrograde tracing methods was employed to distinguish populations of motoneurons supplying different motor unit territories in the feline diaphragm. The compatibility of the tracers—horseradish peroxidase, fast or true blue, diamidino yellow, and fluorogold—was first assessed by applying the different tracers concurrently to separate cut branches of hindlimb and neck muscle nerves. On the basis of these initial observations fast blue, fluorogold, and horseradish peroxidase were chosen to compare the distribution of motoneurons whose axons ran in different primary branches of the phrenic nerve. Motoneurons with different target territories were extensively intermixed throughout most of the phrenic motor nucleus. However, motoneurons innervating the sternal and medial costal part of the diaphragm were distributed more densely in the rostral part of the phrenic motor pool, whereas motoneurons serving the lateral costal part were concentrated more caudally. Crural motoneurons were intermingled with costal motoneurons in the middle and caudal portions of the nucleus. Motoneurons within the phrenic nucleus are distributed in clusters. Such clusters commonly contained motoneurons labelled from two or more primary branches. Thus, the highly ordered topography of muscle units in the diaphragm is not mirrored by the intraspinal distribution of phrenic motoneur

ISSN:0092-7317    

DOI:10.1002/cne.902920308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractAn antiserum against conjugated histamine was used to study the distribution of histaminergic neurons in the CNS of the lampreyLampetra fluviatilis. Numerous histamine‐immunoreactive cell bodies were detected in the dorsal and ventral hypothalamic nuclei and in the adjacent postinfundibular commissural ncleus. Histamine‐immunoreactive fibers of high density were present in the ventral hypothalamus, and fibers could also be traced dorsally from the hypothalamus to the corpus striatum and septal nucleus where they appeared to terminate in dense plexuses. Another, smaller group of histamine‐immunoreactive perikarya was observed in the border area between mesencephalon and rhombencephalon, near the caudal pole of the mesencephalic reticular nucleus. Sparsely distributed histamine‐immunoreactive fibers were present in the ventral mesencephalon. The distribution of histaminergic neurons in cyclostomes, which diverged very early from the main vertebrate line, shows similarities with the corresponding systems in the CNS of amphibians and mammals, which suggests that histaminergic neuronal systems are phylogenetically old and have been conserved during ev

ISSN:0092-7317    

DOI:10.1002/cne.902920309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe development of the rat barrel field cortex was investigated with an antibody to the axonal membrane‐specific phosphoprotein GAP‐43 in order to examine the developmental pattern of afferent projections, and with cytochrome oxidase histochemistry and Nissl stains to reveal the morphogenesis of cortical barrels.On the first two days after birth, GAP‐43 immunostaining in the cortical plate was light and diffuse, then became intense in the presumptive layer IV of the parietal cortex on PND3 (day of birth = PND0). Immunoreactive densities were visible as small, focal patches within the centers of prospective barrels. These densities increased in size and intensity over the next few days and then diminished abruptly. On PnD7, the distribution of GAP‐43 was coextensive with barrels, as defined by cytochrome oxidase histochemistry and Nissl staining. GAP‐43 virtually disappeared from the barrels after PND7. From the second postnatal week, GAP‐43 immunostaining was evident in the septa between barrels and in the dysgranular regions of SI cortex. This pattern of GAP‐43 distribution was complementary to the pattern of cytochrome oxidase activity, and persisted into maturity.In an attempt to identify possible source(s) of GAP‐43 positive afferents in the developing barrels, we examined the effects of altering the sensory periphery on the distribution of GAP‐43 immunostaining in the cortex. Rat pups had row C whiskers cauterized on PND0 and were sacrificed on PND3 or PND5. Whereas immunopositive densities corresponding to intact whiskers developed in a normal, punctate pattern, cortical representation of the lesioned whiskers formed a continuous band of labeling that was evident as early as PND3.We argue that the disjunctive expression of GAP‐43 in the barrel field reflects the pattern of distribution of afferents (most likely from the ventrobasal thalamic nucleus) to the barrel field cortex, and that this pattern may be instructive in the formation of barrels as cytoarchitectonic units. The rapid alteration in patterns of immunostaining following whisker lesions lends further support to the conclusion that the “barrel template” is conveyed to the neocortex by incoming afferents. The possible significance of the transient expression of GAP‐43 in the maturing

ISSN:0092-7317    

DOI:10.1002/cne.902920310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractAccording to previous studies, the avian n. dorsolateralis posterior thalami (DLP) receives visual and somatosensory afferents. While some authors (e. g., Gamlin and Cohen:J. Comp. Neurol. 250:296–310, '86) proposed a distinction between a visual caudal (DLPc) and a somatosensory rostral (DLPr) part, other authors (e. g., Wild:Brain Res. 412:205–223, '87) could not confirm such a differentiation. The aim of the present experiment was to study with physiological and anatomical methods the proposed parcellation of the DLP into various components dealing with different modalities.The physiological properties of the DLP of the pigeon were analysed with extracellular single unit recordings. With the same approach, neurons of the n. dorsalis intermedius ventralis anterior (DIVA), a somatosensory relay nucleus in the dorsal thalamus, were also analysed. The afferents of the DLP were studied by using anatomical tract tracing techniques with retrograde and anterograde tracers. The sensory properties of DLP cells revealed that somatosensory, visual, and auditory modalities affect the neuronal firing frequency in this nucleus. All three modalities were present throughout the full caudorostral extent of the DLP. Cells recorded in DIVA responded nearly exclusively to somatosensory stimulation. Unlike the DLP, single units in DIVA generally had smaller receptive fields encompassing only one extremity.The analysis of afferent connections of the DLP by using injections of retrograde and anterograde tracers (HRP, WGA‐HRP, Fast Blue, and Rhodamine‐β‐isothiocyanate) demonstrated extensive projections from the nuclei gracilis et cuneatus (GC) and more sparse projections from the nucleus tractus descendens trigemini (TTD), and the nucleus cuneatus externus (CE). Brainstem afferents of the DLP came from different vestibular nuclei, various areas of the brainstem reticular formation, and the optic tectum. Prosencephalic afferents originated in the n. posteroventralis thalami (PV), the n. ventromedialis posterior thalami (VMP), the n. dorsalis intermedius ventralis anterior (DIVA), and the nucleus reticularis superior pars dorsalis and ventralis (RSd and RSv). Telencephalic afferents of the DLP came from the hyperstriatum accessorium (HA) and a group of cells at the borderline between the hyperstriatum intercalatus superior (HIS) and the hyperstriatum dorsale (HD).The somatosensory afferents of the DLP probably originate from the GC, TTD, and CE, whereas it is likely that the visual input is mediated by the optic tectum. The anatomical source for the acoustic input is unclear. The very long latencies of auditory DLP neurons make it likely that the acoustic input originates at least partly in the reticular formation. The sensory properties and the organization of afferents suggest a general similarity of the DLP to the n. ventromedialis thalami of teleosts and the posterior complex of nuclei

ISSN:0092-7317    

DOI:10.1002/cne.902920311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY