bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neurons labeled from locomotor‐related ventrolateral funiculus stimulus sites in the neonatal rat spinal cord
Authors: Antonino‐Green Deborah M. , Cheng Jianguo , Magnuson David S.K. 
Published: August 2002

AbstractSpinal cord/brainstem preparations from 5‐ to 8‐day‐old rats, maintained in vitro, were used to determine the cells of origin and regions of termination of fibers in the superficial ventrolateral funiculus (VLF) at a site from which rhythmic locomotor‐like activity can be induced. Rhythmic locomotor‐like activity was recorded from lumbar ventral roots after short trains of stimuli (50 Hz for 0.5–2 seconds) delivered to the VLF. Field potential mapping revealed that single VLF stimuli elicited responses in the ipsilateral ventrolateral medulla. Tract‐tracing experiments by using biocytin, pressure‐injected into the VLF, showed that only a small number of brainstem neurons were labeled and these were scattered bilaterally in the ventrolateral and lateral medulla. Dense concentrations of nerve terminals were found in the lateral reticular nucleus ipsilateral to the stimulation site. Labeled spinal cord neurons included a primary population of large cells distributed bilaterally in lamina VII from T13 to L4, with peak numbers in L2 ipsilaterally and in L3 contralaterally. Intracellular recordings revealed that some L2 and L3 neurons with rhythmic responses to VLF stimulation could be activated antidromically from the VLF, with latencies of less than 1.0 msec. These observations led us to speculate that the superficial VLF carries a locomotor‐related tract originating bilaterally in lumbar lamina VII and terminating in the ipsilateral medulla, including the lateral reticular nucleus. This pathway may be part of the spinoreticular or spinoreticulotectal pathway that has been described in many species, the function of which has only loosely been ascribed. J. Comp. Neurol. 442:226–238, 2002. © 2001 Wiley‐Liss, Inc.
Characterization of circular muscle motor neurons of the duodenum and distal colon in the Australian brush‐tailed possum
Authors: Konomi Hiroyuki , Meedeniya Adrian C.B. , Simula Maria E. , Toouli James , Saccone Gino T.P. 
Published: August 2002

AbstractThe motor innervation of the duodenum and distal colon remains uncharacterized within the same species. Our aim was to compare the projections and neurochemical properties of duodenal and distal colon circular muscle motor neurons. Circular muscle motor neurons were retrogradely traced by using a neural tracer in vitro, processed for choline acetyltransferase (ChAT) and nitric oxide synthase (NOS) immunoreactivity and then visualized by using indirect immunofluorescence. A mean of 372 ± 64 and 156 ± 23 neurons (mean ± SEM) were tracer‐labeled within the duodenum and colon, respectively. The ChAT+/NOS− neurons comprised 57.6 ± 6.6% and 39.6 ± 4.4% of all labeled cells in the duodenum and colon, respectively, and projected mainly in the oral direction. Of all labeled cells, the ChAT−/NOS+ neurons comprised 8.5 ± 2.3% in the duodenum and 46.6 ± 5.0% in the distal colon and projected mainly in the anal direction. Of the remainder, 20.6 ± 5.0% and 8.2 ± 2.4% were ChAT+/NOS+ and 13.2 ± 0.9% and 5.6 ± 1.4% were ChAT−/NOS− in the duodenum and distal colon, respectively. Within both regions, the distribution of the ChAT+/NOS− and ChAT−/NOS+ neurons are consistent with the ascending excitatory and descending inhibitory reflexes. The proportion of ChAT−/NOS+ neurons is greater within the colon in comparison with the duodenum. A considerable proportion of duodenal motor neurons were ChAT+/NOS+ and ChAT−/NOS−. These two classes may underlie nonperistaltic motor patterns, which predominate within the duodenum. These findings demonstrate regional differences in the innervation of intestinal circular muscle. J. Comp. Neurol. 443:15–26, 2002. © 2002 Wiley‐Liss, Inc.
Aging and the myelinated fibers in prefrontal cortex and corpus callosum of the monkey
Authors: Peters Alan , Sethares Claire 
Published: August 2002

AbstractIn the rhesus monkey, the myelin sheaths of nerve fibers in area 46 of prefrontal cortex and in splenium of the corpus callosum show age‐related alterations in their structure. The alterations are of four basic types. Most common is splitting of the dense line of myelin sheaths to accommodate electron dense cytoplasm derived from the oligodendroglia. Less common are splits of the intraperiod line to form balloons or blisters that appear to contain fluid, the occurrence of sheaths with redundant myelin, and thick sheaths that are almost completely split so that one set of compact lamellae is surrounded by another set. But despite these alterations in the sheaths, few nerve fibers show axonal degeneration. To quantify the frequency of the age‐related alterations in myelin, transversely sectioned nerve fibers from the splenium of the corpus callosum and from the vertical bundles of nerve fibers within area 46 were examined in electron photomicrographs. The material was taken from 19 monkeys, ranging between 5 and 35 years of age. It was found that the frequency of alterations in myelin sheaths from both locations correlates significantly with age. In area 46, the age‐related alterations also significantly correlate (P < 0.001) with an overall assessment of impairment in cognition, i.e., the cognitive impairment index, displayed by individual monkeys. The correlation is also significant when only the old monkeys are considered as a group. A similar result was obtained previously in our examination of the effects of age on the myelin sheaths of nerve fibers in primary visual cortex (Peters et al. [2000] J Comp Neurol. 419:364–376). However, in the corpus callosum the myelin alterations correlate significantly with only one component of the cognitive impairment index, namely the delayed nonmatching to sample task with a 2‐minute delay. It is proposed that age‐related myelin alterations are ubiquitous and that the correlations between their frequency and impairments in cognition occur because the conduction velocity along the affected nerve fibers is reduced, so that the normal timing sequences within neuronal circuits break down. J. Comp. Neurol. 442:277–291, 2002. © 2001 Wiley‐Liss, Inc.
Retinal organization in the bcl‐2‐overexpressing transgenic mouse
Authors: Strettoi Enrica , Volpini Maila 
Published: August 2002

AbstractNaturally occurring cell death is believed to play a major role during the development of the nervous system in the establishment of neuronal architecture. Here we study the effects of cell death inhibition by using a transgenic mouse in which the powerful antiapototic gene bcl‐2 is expressed in neurons. The retina of this mouse reveals that the general neuronal plan has been maintained. However, bcl‐2 overexpression leads to altered frequencies of the major cell types in the retina. Thus, it is possible to estimate cell‐type‐specific rates of apoptosis by observing the increases in numbers of cells in the bcl‐2‐overexpressing transgenic mouse. J. Comp. Neurol. 446:1–10, 2002. © 2002 Wiley‐Liss, Inc.
Calcyon in the rat brain: Cloning of cDNA and expression of mRNA
Authors: Zelenin Sergey , Aperia Anita , Diaz Heijtz Rochellys 
Published: August 2002

AbstractCalcyon is a 24 kD protein recently cloned from a human brain cDNA library and shown to interact with the dopamine receptor 1 (D1R) of D1‐like receptors. This interaction shifts the effector coupling of D1R to stimulate a calcium signaling pathway, without influencing the D1R‐adenylyl‐cAMP pathway. To obtain more knowledge about the potential role of calcyon in the brain, we cloned rat calcyon cDNA and studied its distribution in the brain. Northern blot analysis and RT‐PCR revealed that rat calcyon mRNA was expressed only in the brain. With the use of the in situ hybridization technique, we studied rat calcyon mRNA distribution in the brain and related it to the distribution of D1R and dopamine receptor 5 (D5R) mRNAs. Prominent calcyon mRNA signals were found in several brain regions, including hippocampus, hypothalamus, cerebellum, and medial prefrontal cortex. Less abundant calcyon mRNA expression was observed in the dorsal striatum region, where D1R mRNA is highly expressed and where D1R/cAMP‐DARPP‐32 signaling pathway is of great functional importance. The strongest expression of D5R mRNA was found in the hippocampus and cerebellum, where D1R mRNA expression was relatively low. In conclusion, rat calcyon appears to be a brain specific protein. There is a certain overlap between calcyon mRNA distribution and that of the D1R and D5 mRNAs, indicating that calcyon might be associated not only with D1R but also with D5R. J. Comp. Neurol. 446:37–45, 2002. © 2002 Wiley‐Liss, Inc.
Development of convergent synaptic inputs to subpopulations of autonomic neurons
Authors: Anderson Rebecca L. , Jobling Phillip , Matthew Sue E. , Gibbins Ian L. 
Published: August 2002

AbstractVisceromotor neurons in mammalian prevertebral sympathetic ganglia receive convergent synaptic inputs from spinal preganglionic neurons and peripheral intestinofugal neurons projecting from the enteric plexuses. Vasomotor neurons in the same ganglia receive only preganglionic inputs. How this pathway‐specific pattern of connectivity is established is unknown. We have used a combination of immunohistochemical, ultrastructural, and electrophysiological techniques to investigate the development of synaptic inputs onto visceromotor and vasomotor neurons in the celiac ganglion of guinea pigs. Functional synaptogenesis occurred primarily from early fetal (F30–F35) to midfetal (F36–F45) stages, after the neurochemical differentiation of vasomotor and visceromotor neurons but before establishment of their electrophysiological phenotypes. Intestinofugal inputs were detected only on presumptive visceromotor neurons located primarily in medial regions of the ganglion. The number of ultrastructurally identified synaptic profiles increased in parallel with functional synaptogenesis, especially in medial regions, where dendritic growth rates also were higher. However, the expression of immunoreactivity to choline acetyltransferase in the terminals of inputs was very low until late fetal stages, after functional transmission already had been established. These results show that peripheral intestinofugal neurons directly establish appropriate functional connections with their target visceromotor neurons simultaneously with the development of functional preganglionic inputs to both visceromotor and vasomotor neurons. It seems likely that synaptogenesis occurs independently of the neurochemical differentiation of the target neurons but is closely related to the pathway‐specific dendritic development of those neurons. J. Comp. Neurol. 447:218–233, 2002. © 2002 Wiley‐Liss, Inc.
Distribution of postsynaptic GABAa receptor aggregates in the deep cerebellar nuclei of normal and mutant mice
Authors: Garin Nathalie , Hornung Jean‐Pierre , Escher Gérard 
Published: August 2002

AbstractIn the central nervous system, the aggregation of receptors is crucial for synapse formation and function. To study the role of presynaptic terminals in the maintenance of postsynaptic specializations, we analyzed the synaptic contacts between Purkinje cells and neurons of the deep cerebellar nuclei in two in vivo models: the Lurcher and Purkinje cell‐deficient (PCD) mutant mice. These mutants lose their Purkinje cells at different postnatal stages. By using confocal scanner microscopy and immunohistochemistry, we studied the distribution of the α subunit of the γ‐aminobutyric acid (GABA)A receptor (GABAARα1) and gephyrin, one of its anchoring proteins, in relation to the distribution of presynaptic markers, glutamic acid decarboxylase (GAD), or synaptophysin. In Lurcher the distribution of GABAA receptor aggregates on the membrane of postsynaptic neurons was not affected by the important loss of GAD‐positive terminals, whereas in PCD, the number of large GABAA receptor aggregates increased. In both mutants the number of aggregates of gephyrin decreased. Most of these remaining aggregates were clustered to form groups, some of which were in front of GAD‐positive terminals. This study shows, for the first time, the localization of GABAARα1 in Lurcher and PCD mutant mice. It clearly establishes that GABAARα1 and gephyrin are differentially affected by deafferentation. Because the receptor aggregates are maintained while the gephyrin aggregates are lost, as a result some receptor aggregates are not associated with any gephyrin. These two postsynaptic components appeared to be regulated by different mechanisms. J. Comp. Neurol. 447:210–217, 2002. © 2002 Wiley‐Liss, Inc.
Gonadal hormones are responsible for maintaining the integrity of spine synapses in the CA1 hippocampal subfield of female nonhuman primates
Authors: Leranth Csaba , Shanabrough Marya , Redmond D. Eugene 
Published: August 2002

AbstractIt is well established that gonadal hormonal manipulation results in morphologic changes in the rat hippocampus. The great similarities in the hippocampal formation between nonhuman primates and humans, as well as the differences in this structure between humans and rats, led to this investigation of whether hormonal manipulation in female subhuman primates influences pyramidal cell spine density in the CA1 hippocampal subfield, as it does in rats. African green monkeys (Cercopithecus aethiops sabaeus) were ovariectomized, and half of the animals received estrogen replacement therapy. One month later, the monkeys were killed. In the first group of experiments, pyramidal cell spines were analyzed on Golgi‐impregnated material taken from the CA1 hippocampal subfield. In the second experiment, unbiased electron microscopic stereologic calculations were performed to estimate the volumetric density of spine synapses in the same hippocampal subfield. Analysis of the Golgi‐impregnated material showed that the spine density of CA1 pyramidal cells is much lower in the ovariectomized animals than in ovariectomized and estrogen‐replaced monkeys. The unbiased, electron microscopic, stereologic calculation confirmed the light microscopic observation. The volumetric density (number of spine synapses/μ m3) of spine synapses was significantly lower (43.33%) in the ovariectomized animals than in ovariectomized and estrogen‐replaced monkeys. Because the hippocampus is involved in specific mnemonic functions, this observation highlights the importance of hormone replacement therapy in postmenopausal conditions. J. Comp. Neurol. 447:34–42, 2002. © 2002 Wiley‐Liss, Inc.
Neuroanatomical studies of period gene expression in the hawkmoth, Manduca sexta
Authors: Wise Sarah , Davis Norman T. , Tyndale Elizabeth , Noveral Jocelyne , Folwell Mary Grace , Bedian Vahe , Emery Ivette F. , Siwicki Kathleen K. 
Published: August 2002

AbstractIn the nervous system of the hawkmoth, Manduca sexta, cells expressing the period (per)gene were mapped by in situ hybridization and immunocytochemical methods. Digoxigenin‐labeled riboprobes were transcribed from a 1‐kb M. sexta
per cDNA. Monoclonal anti‐PER antibodies were raised to peptide antigens translated from both M. sexta and Drosophila melanogaster
per cDNAs. These reagents revealed a widespread distribution of per gene products in M. sexta eyes, optic lobes, brains, and retrocerebral complexes. Labeling for per mRNA was prominent in photoreceptors and in glial cells throughout the brain, and in a cluster of 100–200 neurons adjacent to the accessory medulla of the optic lobes. Daily rhythms of per mRNA levels were detected only in glial cells. PER‐like immunoreactivity was observed in nuclei of most neurons and glial cells and in many photoreceptor nuclei. Four neurosecretory cells in the pars lateralis of each brain hemisphere exhibited both nuclear and cytoplasmic staining with anti‐PER antibodies. These cells were positively identified as Ia1 neurosecretory cells that express corazonin immunoreactivity. Anti‐corazonin labeled their projections in the brain and their neurohemal endings in the corpora cardiaca and corpora allata. Four pairs of PER‐expressing neurosecretory cells previously described in the silkmoth, Anthereae pernyi, are likely to be homologous to these PER/corazonin‐expressing Ia1 cells of M. sexta. Other findings, such as widespread nuclear localization of M. sexta PER and rhythmic expression in glial cells, are reminiscient of the period gene of D. melanogaster, suggesting that some functions of per may be conserved in this lepidopteran species. J. Comp. Neurol. 447:366–380, 2002. © 2002 Wiley‐Liss, Inc.
Peripheral patterns of terminal innervation of vestibular primary afferent neurons projecting to the vestibulocerebellum in the gerbil
Authors: Purcell Ian M. , Perachio Adrian A. 
Published: August 2002

AbstractRetrograde transganglionic labeling techniques with biotinylated dextran amine (BDA) were used to examine the terminal field structure and topographical patterns of innervation within the vestibular sensory end organs of vestibular primary afferent neurons projecting to the cerebellar uvula/nodulus and flocculus lobules in the gerbil. Robust, dark labeling in the cristae ampullares suggested that the vast majority of the terminals of afferent neurons were of the dimorphic type. The majority (94% to the uvula/nodulus and 100% to the flocculus) innervates the peripheral zones of each of the three semicircular canal cristae. Comparison of the type and distribution of terminals across the canalicular sensory neuroepithelium with morphophysiological studies in chinchilla suggests that the labeled population consists predominantly of peripheral terminal fields of lower‐to‐intermediate gain, more regularly firing, tonic afferents. For otolith organ‐related afferents, the uvula/nodulus receives strong inputs from primary otolith afferent neurons identified as dimorphic in type that predominately innervate the peristriolar zones of the utricular and saccular maculae. No direct otolith organ‐related inputs to the flocculus were observed. In contrast to the canal afferents, the types and locations of labeled otolith afferent terminals suggest that they largely consist of irregularly firing, high‐gain, phasic neurons. J. Comp. Neurol. 433:48–61, 2001. © 2001 Wiley‐Liss, Inc.
Structural abnormalities develop in the brain after ablation of the gene encoding nonmuscle myosin II‐B heavy chain
Authors: Tullio Antonella N. , Bridgman Paul C. , Tresser Nancy J. , Chan Chi‐Chao , Conti Mary Anne , Adelstein Robert S. , Hara Yoshinobu 
Published: August 2002

AbstractAblation of nonmuscle myosin heavy chain II‐B (NMHC‐B) in mice results in severe hydrocephalus with enlargement of the lateral and third ventricles. All B‐/B‐ mice died either during embryonic development or on the day of birth (PO). Neurons cultured from superior cervical ganglia of B‐/B‐ mice between embryonic day (E) 18 and P0 showed decreased rates of neurite outgrowth, and their growth cones had a distinctive narrow morphology compared with those from normal mice. Serial sections of E12.5, E13.5, and E15 mouse brains identified developmental defects in the ventricular neuroepithelium. On E12.5, disruption of the coherent ventricular surface and disordered cell migration of neuroepithelial and differentiated cells were seen at various points in the ventricular walls. These abnormalities resulted in the formation of rosettes in various regions of the brain and spinal cord. On E13.5 and E15, disruption of the ventricular surface and aberrant protrusions of neural cells into the ventricles became more prominent. By E18.5 and P0, the defects in cells lining the ventricular wall resulted in an obstructive hydrocephalus due to stenosis or occlusion of the third ventricle and cerebral aqueduct. These defects may be caused by abnormalities in the cell adhesive properties of neuroepithelial cells and suggest that NMHC‐B is essential for both early and late developmental processes in the mammalian brain. J. Comp. Neurol. 433:62–74, 2001. © 2001 Wiley‐Liss, Inc.
Muscarinic receptor M2 in cat visual cortex: Laminar distribution, relationship to γ‐aminobutyric acidergic neurons, and effect of cingulate lesions
Authors: Erisir Alev , Levey Allan I. , Aoki Chiye 
Published: August 2002

AbstractAcetylcholine can have diverse effects on visual cortical neurons as a result of variations in postsynaptic receptor subtypes as well as the types of neurons and subcellular sites targeted. This study examines the cellular basis for cholinergic activation in visual cortex via M2 type muscarinic receptors in γ‐aminobutyric acid (GABA)‐ergic and non‐GABAergic cells, using immunocytochemical techniques. At light microscopic resolution, M2 immunoreactivity (‐ir) was seen in all layers except area and sublayer specific bands in layer 4. Subcellularly, M2‐ir occurred in both dendrites and terminals that form symmetric and asymmetric junctions. Layers 5 and 6 were characterized by axosomatic contacts that displayed labeling in the presynaptic component, and layer 6 displayed perikaryal postsynaptic staining, suggesting that corticofugal output neurons may be modulated particularly strongly via M2. Infragranular layers differed from the supragranular layers in that more labeled profiles were axonal than dendritic, indicating a dominant presynaptic effect by acetylcholine via M2 there. Unilateral cingulate cortex cuts caused reduction of cholinergic and noradrenergic fibers in the lesioned hemisphere at light microscopic resolution; at electron microscopic resolution, the synapse density and axonal M2 labeling were reduced, suggesting that M2 was localized presynaptically on extrathalamic modulatory inputs. Dual labeling with GABA in visual cortex layer 5 showed that half of M2‐labeled dendrites originated from GABAergic neurons. Given that only one‐fifth of all cortical dendritic profiles are GABAergic, this prevalence of dual labeling indicates an enrichment of M2 within GABAergic dendrites and, thus, implicates abundant postsynaptic action on GABAergic neurons via M2. In contrast, only one‐tenth of M2‐labeled terminals originated from GABAergic neurons, suggesting that the presynaptic action of acetylcholine via M2 receptors would be more selective for non‐GABAergic terminals. J. Comp. Neurol. 441:168–185, 2001. © 2001 Wiley‐Liss, Inc.
An averaged nodal deformation gradient linear tetrahedral element for large strain explicit dynamic applications
Authors: Bonet J. , Marriott H. , Hassan O. 
Published: August 2002

AbstractThis paper presents a new linear tetrahedral element that overcomes the shortcomings in bending dominated problems of the average nodal pressure element presented in Bonet and Burton (Communications in Numerical Methods in Engineering 1998; 14:437–439) Zienkiewicz et al. (Internatinal Journal for Numerical Methods in Engineering 1998; 43:565–583) and Bonet et al. (Internatinal Journal for Numerical Methods in Engineering 2001; 50(1):119–133). This is achieved by extending some of the ideas proposed by Dohrmann et al. (Internatinal Journal for Numerical Methods in Engineering 2000; 47:1549–1568) to the large strain nonlinear kinematics regime. In essence, a nodal deformation gradient is defined by weighted average of the surrounding element values. The associated stresses and internal forces are then derived by differentiation of the corresponding simplified strain energy term. The resulting element is intended for use in explicit dynamic codes (Goudreau and Hallquist, Computer Methods in Applied Mechanics and Engineering 1982; 33) where the use of quadratic tetrahedral elements can present significant difficulties. Copyright © 2001 John Wiley & Sons, Ltd.