bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of choline acetyltransferase‐, serotonin‐, dopamine‐β‐hydroxylase‐, tyrosine hydroxylase‐immunoreactive fibers in monkey primary auditory cortex
Authors: Campbell Michael J. , Lewis David A. , Foote Stephen L. , Morrison John H. 
Published: January 2005

AbstractImmunohistochemical methods were used to visualize choline acetyl‐transferase (ChAT)‐, serotonin‐, dopamine‐β‐hydroxylase (DBH)‐, and tyrosine hydroxylase (TH)‐containing fibers in the primary auditory cortex of the cynomolgus monkey (Macaca fascicularis). Each antiserum revealed a subpopulation of axons with a distinct density and laminar distribution. ChAT‐immunoreactive fibers were very dense in superficial layers, particularly in layers I, deep III, and IV, and very sparse in layers V and VI. No immunoreactive cell bodies were evident. Serotonin‐immunoreactive fibers were very dense in all cortical layers but exhibited some subtle laminar differences in fiber size and orientation. The densities of DBH‐ and TH‐immunoreactive fibers were substantially lower than the densities of both ChAT‐ and serotonin‐immunoreactive fibers, particularly in layer IV. However, there were substantial differences between the distribution of TH‐immunoreactive fibers and that of DBH‐immunoreactive fibers. For example, the density of TH‐immunoreactive fibers was substantially greater than that of DBH–immunoreactive fibers in layer I. In addition, TH‐immunoreactive fibers differed from the other three systems in that TH‐immunoreactive fibers exhibited a rostral to caudal gradient of decreasing density.This is the first characterization of the innervation of a specific cortical region by all four of these systems and the first detailed description of the cholinergic innervation of a primate neocortical region utilizing a specific anti‐ChAT antiserum. These striking differences in density and laminar distribution suggest that the subcortical extrathalamic systems furnishing these axons differ significantly in their modulation of cortical auditory processing. These data extend observations of previous studies which revealed that the expansion and specialization of the primate neocortex is accompanied by a pronounced regional and laminar differentiation in the intracortical distribution of these highly divergent, extrathalamic afferents.
Vasopressin cells in the medial amygdala of the rat project to the lateral septum and ventral hippocampus
Authors: Caffé A. R. , van Leeuwen F. W. , Luiten P. G. M. 
Published: January 2005

AbstractThe rat brain contains a large number of vasopressin (VP) immunoreactive fibers, the sites of origin of which have not yet been established completely. For instance, the sources of VP fiber systems in the amygdala, ventral hippocampus (VH), mediodorsal thalamic nucleus, ventral tegmental area, and dorsal raphe yet remain obscure. These VP fibers may originate in any of the recently described extrahypothalamic VP cell groups, viz., medial amygdaloid nucleus (AME), dorsomedial hypothalamic nucleus, or locus coeruleus, since VP efferents from these cells still remain to be demonstrated. In search of AME VP efferents three approaches were followed: (1) the Phaseolus vulgaris anterograde tracing method, (2) immunocytochemistry after AME lesioning, and (3) retrograde transport of a fluorescent dye in combination with immunofluorescence. The results demonstrate that VP cells in the AME project to (1) the lateral septum (LS) by the ventral amygdalofugal pathway and (2) the VH via the amygdalohippocampal transition zone. In addition, the VP projection from the bed nucleus of the stria terminalis (BST) to the LS was confirmed. There was no indication that VP cells in the AME project through the amygdalotegmental pathway to the medulla oblongata and spinal cord. The results support the possibility that the BST and AME are an anatomical entity that may be part of the central loci controlling sexual processes in the rat.
Intrinsic circuitry involving the local axon collaterals of corticothalamic projection cells in mouse SmI cortex
Authors: White Edward L. , Keller Asaf 
Published: January 2005

AbstractThe objective of this study was to identify the components involved in a local synaptic circuit in the mouse cerebral cortex. The local axon collaterals of corticothalamic (CT) projection cells in the posteromedial barrel subfield area of primary somatosensory cortex were labeled by the retrograde transport of horseradish peroxidase injected into the ipsilateral thalamus. Thalamocortical (TC) axon terminals in the same region of cortex were labeled by lesion induced degeneration. CT axon terminals synapsed preferentially with dendritic shafts, whereas TC axon terminals synapsed mainly with dendritic spines. Some dendrites received both CT and TC synapses. Dendrites postsynaptic to CT axon terminals were reconstructed from serial thin sections; on the basis of their shapes and synaptic connections, these dendrites were interpreted to belong to nonspiny multipolar cells. These results indicate that a reciprocal synaptic relationship exists in the cortex between nonspiny multipolar cells and CT projection cells. Both CT projection cells and nonspiny multipolar neurons have been shown previously to receive TC synapses (White and Hersh: J. Neurocytol. 11:137–157, '82; White, Benshalom, and Hersch: J. Comp. Neurol 229:311–320, '84). These findings imply that a0 triadic relationship involving afferent input and populations of CT projection and intrinsic neurons is a basic feature of the synaptic organization of the cerebral cortex.
Distribution of acetylcholinesterase in the hippocampal region of the rabbit: II. Subiculum and hippocampus
Authors: Geneser Finn A. 
Published: January 2005

AbstractThe distribution of acetylcholinesterase (AChE) has been examined in two areas of the hippocampal region of the adult rabbit, viz., the subiculum and the hippocampus. AChE was demonstrated histochemically by using a modification of the Koelle copper thiocholine method. Moderate amounts of AChE were observed in the subiculum, whereas the hippocampus had a high content of this enzyme. In each area, the AChE staining displayed a distinctly stratified pattern which has been compared in detail with the fields and layers defined on the basis of cyto‐ and fibro‐architectonics. Most of the enzyme activity was confined to the neuropil, but a considerable number of nerve cell bodies were moderately or intensely stained in both the subiculum and the hippocampus.In the subiculum, the plexiform layer showed a complex distribution of AChE, displaying four horizontal, differently stained subzones. In the cell layer, the staining was most intense in two narrow bands, one being immediately beneath the plexiform layer and the other bordering directly on the white matter. The remaining major part of the subicular cell layer generally had a low AChE content. In regio superior of the hippocampus, intense staining was observed in the deep part of the molecular layer, in a narrow suprapyramidal zone of the stratum radiatum, and in the stratum oriens. In regio inferior, very high AChE activity was present in the molecular layer, in two narrow bands bordering the mossy fiber layer superficially and at depth, and in the stratum oriens. The pyramidal cell bodies and the mossy fibers were unstained.The distribution of AChE in the rabbit was compared with that in the rat and guinea pig; the latter two have been reported. The staining patterns of all three species share many conspicuous histochemical features, though notable species‐specific traits do exist.Detailed consideration is given to possible structural correlates of the AChE observed in the two areas, in particular the relation to fiber systems known from either normal material or experimental investigations. A considerable portion of the enzyme is probably contained in afferents of septal origin, but it seems very likely that some of the AChE is associated with other fiber systems, the identity of which are unknown at present. A possible role of some of the AChE observed in the hippocampal region in the hydrolysis of substance P and enkephalin is discussed briefly.
The origins of cholinergic and other subcortical afferents to the thalamus in the rat
Authors: Hallanger Ann E. , Levey Allan I. , Lee Henry J. , Rye David B. , Wainer Bruce H. 
Published: January 2005

AbstractThe origins of the cholinergic and other afferents of several thalamic nuclei were investigated in the rat by using the retrograde transport of wheat germ agglutinin conjugated‐horseradish peroxidase in combination with the immunohistochemical localization of choline acetyltransferase immunoreactivity. Small injections placed into the reticular, ventral, laterodorsal, lateroposterior, posterior, mediodorsal, geniculate, and intralaminar nuclei resulted in several distinct patterns of retrograde labelling. As expected, the appropriate specific sensory and motor‐related subcortical structures were retrogradely labelled after injections into the principal thalamic nuclei. In addition, other basal forebrain and brainstem structures were also labelled, with their distribution dependent on the site of injection. A large percentage of these latter projections was cholinergic.In the brainstem, the cholinergic pedunculopontine tegmental nucleus was retrogradely labelled after all thalamic injections, suggesting that it provides a widespread innervation to the thalamus. Neurons of the cholinergic laterodorsal tegmental nucleus were retrogradely labelled after injections into the anterior, laterodorsal, central medial, and mediodorsal nuclei, suggesting that it provides a projection to limbic components of the thalamus. Significant basal forebrain labelling occurred only with injections into the reticular and mediodorsal nuclei. Only injections into the reticular nucleus resulted in retrograde labelling of the cholinergic neurons in the nucleus basalis of Meynert.The results provide evidence for an organized system of thalamic afferents arising from cholinergic and noncholinergic structures in the brainstem and basal forebrain. The brainstem structures, especially the cholinergic pedunculopontine tegmental nucleus, appear to project directly to principal thalamic nuclei, thereby providing a possible anatomical substrate for mediating the well‐known facilitory effects of brainstem stimulation upon thalamocortical transmission.
Comparative distribution of mRNAs for glutamic acid decatrboxylase, tyrosine hydroxylase, and tachykinins in the basal ganglia: An in situ hybridization study in the rodent brain
Authors: Chesselet Marie‐Francoise , Weiss Linda , Wuenschell Carol , Tobin Allan J. , Affolter Hans‐Urs 
Published: January 2005

AbstractNeurotransmitter‐related messenger RNAs were detected by in situ hybridization in sections of rat and mouse brains by using 35S‐radiolabelled RNA probes transcribed from cDNAs cloned in SP6 promoter‐containing vectors. The distribution of messenger RNAs for glutamic acid decarboxylase, tachykinins (substance P and K), and tyrosine hydroxylase was examined in the striatum, pallidum, and substantia nigra. Dense clusters of silver grains were observed with the RNA probe complementary of the cellular messenger RNA for glutamic acid decarboxylase (antisense RNA) over most large neurons in the substantia nigra pars reticulata and medium‐sized to large neurons in all pallidal subdivisions. A few very densely and numerous lightly labelled medium‐sized neurons were present in the striatum. Among the areas examined, only the striatum contained neurons labelled with the antisense tachykinin RNA. Most of these neurons were of medium size, and a few were large. With the antisense tyrosine hydroxylase RNA, silver grains were found over neurons of the substantia nigra pars compacta and adjacent A10 and A8 dopaminergic cell groups. No signal was observed with RNAs identical to the cellular messenger RNA for glutamic acid decarboxylase or tachykinin (sense RNA). These results show a good correlation with immunohistochemical studies, suggesting that documented differences in the distribution and the level of glutamic acid decarboxylase, tyrosine hydroxylase, and substance P immunoreactivities in neurons of the basal ganglia are related to differences in the level of expression of the corresponding genes rather than to translation accessibility, stability, or transport of the gene products.
Spatiotemporal convergence and divergence in the rat S1 “Barrel” cortex
Authors: Armstrong‐James Michael , Fox Kevin 
Published: January 2005

AbstractThe size and response magnitude of receptive fields were evaluated for cells in the rat cortical barrel‐field by using standard vibrissal deflections of 1.14°. Such stimuli fell within the plateau region of stimulus‐response curves. The responses of all neurones to all vibrissae within and surrounding centre‐receptive fields were analysed for probability and latency of response. It was found that cells in supragranular layers had small centre‐receptive fields (average 1.6 vibrissae) with small excitatory surrounds (1.5 vibrissae) while cells in the granular layers had small, powerful centre‐receptive fields (1.4) with moderately large excitatory surrounds (2.6). Neurones in infragranular layers possessed large but weak centre‐receptive fields (2.6) with large surrounds (3.5).Sixty‐four neurones in layer IV were studied, the precise locations of which were identified by using dye lesioning and cytochrome oxidase staining. There were no differences in receptive field size for cells within septa and barrel hollows, but the latter were twice as likely to produce two or more spikes per stimulus from the principal vibrissa (65% against 33%). Histological analysis showed that the principal vibrissa was synonymous with the appropriate vibrissa for the barrel on 86% (55 of 64) of occasions. A quantitative analysis of convergent input to three neighbouring barrels (E1, E2, and D1) showed considerable graded overlap of receptive field surrounds, although facial hair adjacent to the mystacial pad only influenced cells on the edge of the barrel‐field. Individual vibrissae exhibited significant divergent input to adjacent inappropriate barrels, being preferentially directed to distant septal rather than barrel hollow cells. An analysis of latencies showed that 40% of barrel hollow cells and 48% of barrel septal cells responded at short (< 10 ms) latencies to their appropriate vibrissa. In contrast, responses to inappropriate vibrissae were overwhelmingly of long latency (10‐ > 30 ms), only 2% of inappropriate responses from barrel hollow cells and 13% from septal cells being of short latency. These results suggest that direct inputs largely project to appropriate barrels. The possibility that divergent inputs are generated by intracortical mechanisms is discussed.
Ultrastructural observations of the development of the fourth ventricular roof in the mouse brain
Authors: Oda Yoshio , Nakanishi Isao 
Published: January 2005

AbstractThe developmental changes of the fourth ventricular roof of the brain in mouse fetuses and neonates were observed by scanning and transmission electron microscopy with particular attention to the caudal portion where a median foramen might be formed during the fetal period. The fourth ventricular roof was continuously paved with a single layer of cuboidal or squamous neuroepithelial cells with poorly developed basement membrane until the 12th intrauterine day when the primitive choroid plexus appeared at the middle portion of the roof. With development of the choroid plexus, the roof caudal to the choroid plexus (membranous roof) became thinner, and it was mostly lined with a single layer of flat ependymal cells having cilia and microvilli and resting on a continuous basement membrane. These ependymal cells were connected with one another by a gap junction or an intermediate junction for the entire period examined, except at the 13th to 14th intrauterine days, during which the interependymal clefts were transiently widened up to 2 μm in width, in places, without disruption of the continuous basement membrane. Neither a median aperture nor wide intercellular pores were formed in the membranous roof during the fetal or neonatal term.
Topographic organization of convergent projections to the thalamus from the inferior colliculus and spinal cord in the rat
Authors: Ledoux Joseph E. , Ruggiero David A. , Forest Ronni , Stornetta Ruth , Reis Donald J. 
Published: January 2005

AbstractThe purpose of this study was to identify thalamic areas receiving convergent sensory inputs from acoustic and spinal projection systems in the rat. The topographic distribution of afferents to the thalamus from the inferior colliculus and spinal cord was examined by using WGA‐HRP as an anterograde axonal tracer. Following injections in the inferior colliculus, terminal labeling was present in ventral, medial, and dorsal divisions of the medial genicuate body (MGB) and in adjacent areas of the posterior thalamus, including the posterior limitans nucleus, the posterior intralaminar nucleus, the marginal zone, the peripeduncular region, the lateral or parvicellular part of the subparafascicular nucleus, and a region intercalated between the posterior limitans nucleus and the suprageniculate nucleus. In the caudal thalamus spinal projections remained in the reticular formation medial to the collicular terminal field. At intermediate levels of the MG, however, the spinal projection began to overlap the collicular field, terminating in the medial division of the MG and in the posterior intralaminar nucleus, the marginal zone, the lateral subparafascicular nucleus, and the area between the suprageniculate and posterior limitans nuclei. More rostrally, the convergent field expanded to include aspects of the dorsal MG division. The extent to which afferent projections to the thalamus from the inferior colliculus and spinal cord converge is thus graded in the caudorostral plane, with the greatest overlap occurring at the level of the rostral third of the MGB. These observations identify potential areas of acoustic and somesthetic integration and may account for observations of neuronal plasticity in the thalamus in response to the pairing of acoustic and somesthetic inputs.
Topographic representation of the sensory and motor roots of the vagus nerve in the medulla of goldfish, Carassius auratus
Authors: Morita Yasuhiro , Finger Thomas E. 
Published: January 2005

AbstractThe coelomic root of the vagus nerve in goldfish is connected with sensory and motor nuclei of the medulla that are distinct from those serving the orobranchial roots of the same nerve. The primary sensory nucleus for coelomic sensation is itself divisible into medial and lateral subnuclei on the basis of afferent input and immunocytochemistry. The lateral subnucleus receives sensory input from the specialized chewing organ in the posterior pharynx and is poor in both substance P‐like and tyrosine‐hydroxylase‐like immunoreactivities. The medial subnucleus receives input from the subdiaphragmatic gastrointestinal tract and is rich in substance P‐like and tyrosine‐hydroxylase‐like immunoreactivities. The primary sensory fibers that innervate the gastrointestinal tract also project directly to the area postrema and to the vicinity of subdiaphragmatic visceral motor neurons.The vagal motor neuronal pool is divisible into three columns: paramedian (cardiac), medial, and lateral. The paramedian group innervates the heart and is situated in a loosely aggregated column at the boundary zone between the ventricular ependyma and the underlying brainstem. The medial vagal motor neurons innervate the subdiaphragmatic viscera, while the lateral column motor neurons innervate the posterior pharynx and muscles of the chewing organ. The motor neurons in this motor column are arranged in a topographic rostrocaudal order within the motor column according to the muscle of innervation.Thus both the general visceral sensory and general visceral motor nuclei of the medulla are organized into functional domains. Furthermore, in the goldfish, the special visceral (gustatory) and general visceral sensory nuclei form a continuous series in the medulla with the external and oral systems represented anteriorly and the pharyngeal and digestive systems represented posteriorly.
Cellular and synaptic morphology of a feeding motor circuit in Aplysia californica
Authors: Kreiner Thane , Kirk Mark D. , Scheller Richard H. 
Published: January 2005

AbstractThe cellular and synaptic morphology of a component of the feeding motor circuit in Aplysia californica was examined with light and electron microscopic techniques. The circuit consists of a pair of inhibitory premotor interneurons, B4 and B5, as well as two motoneurons, B15 and B16, which innervate the accessory radula closer muscle. The neurons have wide, varicose arborizations in the buccal ganglion neuropil. All four of these neurons are cholinergic, and in addition, B15 contains immunoreactivity to sera raised against small cardioactive peptide B. Varicose processes in the accessory radula closer muscle are immunoreactive with antisera against several neuropeptides. We identified specific neuromuscular junctions by visualizing horseradish peroxidase uptake in recycled synaptic vesicles. Direct innervation of the accessory radula closer muscle by B15 and B16 is demonstrated by experiments in which horseradish peroxidase is transported from motoneuronal soma to the terminals on muscle fibers. In addition, specific synaptic contacts between B4 and B5 and each of the motoneurons are observed in the buccal ganglion neuropil. Finally, multiple contacts consistent with peptidergic, serotoninergic, and cholinergic synapses are made onto the neurons, suggesting that a variety of transmitters modulate motor output at each level of the hierarchical circuit. These results support the physiological evidence suggesting the involvement of neuropeptides as well as “classical” transmitters in the modulation of circuitry governing feeding behavior in Aplysia.