bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dorsal raphe serotoninergic branching neurons projecting both to the lateral geniculate body and superior colliculus: A combined retrograde tracing–immunohistochemical study in the rat
Authors: Villar Marcelo J. , Vitale Maria L. , Hökfelt Tomas , Verhofstad Albert A. J. 
Published: January 2005

AbstractInjections of HRP into the superior colliculus labelled cells in the lateral cell groups of the dorsal raphe nucleus. The cytoarchitectural features and location of these cells showed remarkable similarities with those known to project to the lateral geniculate body, and, therefore, the possible existence of branching neurons in the dorsal raphe nucleus projecting to these two visual structures was tested. Injections into the lateral geniculate body and the superior colliculus of several fluorescent tracers—namely, Fast Blue, Fluoro‐Gold, propidium iodide, rhodamine‐B‐isothiocyanate, and Diamidino Yellow, used in different combinations, showed single‐ and double‐labelled neurons in the lateral wings of the dorsal raphe nucleus. In order to verify the chemical nature of these cells, the tissue was processed for immunofluorescence with serotonin antibodies. The results obtained showed several triple‐labelled cells exhibiting two fluorescent tracers as well as 5‐hydroxytryptamine‐like immunoreactivity. Some immunonegative tracer‐positive cells were also observed, suggesting their nonserotoninergic nature. Finally, electrolytic lesions of the lateral wings of the dorsal raphe nucleus caused a gradual disappearance of serotonin‐immunoreactive fibers in these visual areas following different survival times. This correlated well with a decrease in the serotonin content studied by high‐pressure liquid chromatography.These results support a role of the serotoninergic dorsal raphe projection to the lateral geniculate body and to the superior colliculus in the processing of visual information, and they suggest that serotonin may have a coordinating influence on primary visual centers.
Motor nuclei of peroneal muscles in the cat spinal cord
Authors: Horcholle‐Bossavit G. , Jami L. , Thiesson D. , Zytnicki D. 
Published: January 2005

AbstractThe cat peroneal muscles have been used in numerous investigations dealing with the physiological properties of motor units, muscle spindles, and Golgi tendon organs. This report presents a study of the organization of peroneal motor pools in the cat spinal cord by means of retrograde axonal transport of horseradish peroxidase from individual muscles to the corresponding motoneurons. The motor nuclei of peroneus longus (PL), peroneus brevis (PB), and peroneus tertius (PT) muscles formed thin columns in the lateral part of the ventral horn in spinal segments L6–S1. In the transverse plane, the PT and PL nuclei occupied, respectively, dorsolateral and ventromedial positions, with PB nucleus in an intermediate position overlapping with the other two nuclei. Measurements of cell body diameters allowed identification of α and γ subgroups in peroneal motoneuron populations. The average numbers of motoneurons were about 96 α and 60 γ in PL, 75 α and 54 γ in PB, and 34 α and 23 γ in PT. Comparison with data from electrophysiological studies indicated that whole populations of motoneurons were labeled in each motor nucleus. The proportions of γ motoneurons were the same, and cell bodies of γ motoneurons had similar sizes in the three peroneal populations. In contrast, α motoneurons were significantly smaller in PB than in the two other pools, in keeping with the fact that PB contains a proportion of slow motor units larger than the two other muscles. In large samples of homonymous motoneurons, the numbers of first‐order dendrites correlated linearly with motoneuron sizes.
Postnatal development of cat hind limb motoneurons. II: In vivo morphology of dendritic growth cones and the maturation of dendrite morphology
Authors: Ulfhake Brun , Cullheim Staffan 
Published: January 2005

AbstractThe maturation of dendrite morphology was studied by light and electron microscopy in cat spinal α‐motoneurons intracellularly labeled with horseradish peroxidase. Alpha‐motoneurons supplying the triceps surae (TS) and the intrinsic foot sole (SP) muscles were investigated in kittens from birth to 44–46 days of postnatal (d.p.n.) age.At birth, a large number of dendritic branches displayed growth cones, filopodia, and fusiform processes. The growth cones were of lamellipodial and filopodial types, but intermediate forms also occurred. The growth cones shared several morphological features with the neuritic growth cones studied in vitro. It was suggested that the occurrence of different types of growth cones—even in the same dendrite—may reflect their transformation from one type to the other and the level of growth activity could be inferred from the number and form of the growth cones.About 50–70% of the terminal branches in the dendrites of newborn kittens possessed growth cones, filopodia, and/or fusiform processes. The corresponding figure for preterminal branches was 20–30%, with a clear decrease in incidence when approaching the soma. During the period under study, most of these growth‐associated processes disappeared from the dendrites so that at 44–46 d.p.n. of age only about 10% of the terminal and >1% of the preterminal branches had growth‐associated processes. Analysis of the three‐dimensional distribution of dendritic branches with such processes disclosed that they were relatively more frequent in the medial, rostral, and caudal dendritic territories. It was concluded that the pattern of distribution and disappearence of growth cones, filopodia, and fusiform processes coincided with postnatal longitudinal dendritic growth and the development of the adult dendritic territories described in a preceding paper (Ulfhake et al., '88). Dendritic growth, with respect to length and caliber, also occurred in the absence of growth cones and filopodia. It is suggested that the important role of these processes may be to act as a steering device in establishing the adult distribution and synaptology of the dendrites.Comparison of TS and SP α‐motoneuron dendrite morphology at birth and at 22–24 d.p.n. age showed that the SP neurons lagged in the maturation process.Light and electron microscopic observations indicated that postnatally direct contacts might exist between dendrites and fine blood vessels in the neuropil without any interposing glial sheath. The number of such suspected contacts diminished during the period under study, indicating that the glial ensheathment of the blood vessel takes place, in part, postnatally.
Collateralization of the amygdaloid projections of the rat prelimbic and infralimbic cortices
Authors: Cassell M. D. , Chittick C. A. , Siegel M. A. , Wright D. J. 
Published: January 2005

AbstractPrevious studies indicate that the distribution of corticoamygdaloid neurons in the rat prelimbic (PL) and infralimbic (IL) cortices overlaps with the distribution of neurons projecting to the contralateral medial prefrontal cortex (MPC), insular cortex, mediodorsal thalamus, and dorsal medulla. In view of the poorly differentiated cytoarchitecture of PL and IL, and their designation as cortical regions transitional between the allocortex and isocortex, the present study sought to determine whether several cortical and subcortical projections from these areas arise as collaterals of corticoamygdaloid neurons. Injections of the fluorescent dyes Fast Blue (FB) or bisbenzimide (BB) were made into the amygdaloid complex and the following areas: agranular and granular insular cortices; mediodorsal thalamic nucleus (MD); nucleus tractus solitarii/dorsal medulla (NTS); contralateral amygdaloid complex; and ipsilateral and contralateral MPC. Neurons projecting to the ipsilateral amygdaloid complex were located mainly in layers II and V with fewer cells in layer III. Concomitant injections into the insular cortex, MD, and NTS labeled populations of neurons arranged in laminae that partially overlapped with, but were essentially separate from, corticoamygdaloid neurons. Projections to the insular cortex arose from layers II and V; those to MD arose from layers V and VI. Corticobulbar projections from IL originated from neurons arranged in a thin lamina in the deep part of layer V. Very few neurons projecting to both the amygdaloid complex and any of these areas were observed. Bilateral injections of FB and BB into the amygdaloid complex producted very few double‐labeled cells in PL and IL. Further, in layer V, ipsilaterally projecting corticoamygdaloid neurons tended to be located more deeply than contralaterally projecting neurons. Combined injections of BB and FB into the amygdaloid complex and the contralateral (but not ipsilateral) MPC resulted in significant numbers of double‐labeled neurons in layers II, III, and V of PL and IL. Control injections of fluorescent dyes into the cerebrospinal fluid labeled few neurons in the superficial layers of PL and IL and a combined injection into the amygdaloid complex (FB) and subarachnoid space (BB) resulted in a very small number of double‐labeled cells in layer II only. The results suggest that a significant proportion of neurons in PL and IL projecting to the amygdaloid complex issue collaterals innervating the contralateral MPC. Evidence is discussed that suggests that the interhemispheric collaterals of MPC corticoamygdaloid neurons may serve to correlate the amygdaloid outputs of the MPC bilaterally.
Catecholamine innervation of the human cerebral cortex as revealed by comparative immunohistochemistry of tyrosine hydroxylase and dopamine‐beta‐hydroxylase
Authors: Gaspar Patricia , Berger Brigitte , Febvret Aude , Vigny Annette , Henry Jean Pierre 
Published: January 2005

AbstractThe organization of the cortical monoamine systems, dopamine (DA), and noradrenaline (NA), which have been studied extensively in the rat and more recently in the monkey, had not yet been investigated directly in the human brain. We report here the first systematic account of the regional and laminar distributions of the catecholamine fibers in the human cerebral cortex, using immunohistochemistry of the catecholamine biosynthetic enzymes, tyrosine hydroxylase (TH), and dopamine‐β‐hydroxylase (DBH) in 13 cytoarchitectonic areas (4, 6, 9, 3b, 5, 40, 17, 18, 23, 24, 29, insula, and hippocampus) sampled postmortem.The noradrenergic (NA) innervation, mapped with DBH‐immunoreactivity (DBH‐IR), displayed a characteristic density gradient in the neocortex (highest in the primary sensorimotor areas, decreasing rostrally and caudally) that contrasted with the more uniform density in the limbic cortices (24, 23, 29, insula, hippocampus). NA axons were present in all cortical layers and were least numerous in layer I. The DBH‐IR fibers were only partly TH‐immunostained (10–50%, on double‐labeled sections), suggesting a heterogeneity of the cortical NA axons.The putative dopaminergic (DA) fibers were identified by comparing alternate or double‐immunolabeled (DBH‐TH) sections, as the TH‐IR fibers which contain no DBH‐IR. A DA‐like innervation was present in all cortical areas, with major regional differences in density and laminar distribution, which closely paralleled cytoarchitectural buildups: (1) the DA‐like innervation was densest in the agranular areas, primary and secondary motor areas, anterior cingulate, and insula; it distributed throughout layers I–VI; (2) density was lower in the granular cortices, areas 9 (prefrontal cortex), 23, 3b, 5, 40, and 18, displaying a bilaminar pattern in layers I and V–VI. In all areas, DA‐like fibers were most abundant in the molecular layer, with a predominant distribution in its deepest part. Convoluted and coily fibers represented a unique morphologic aspect of the CA innervation in the human cortex.These findings are in agreement with findings in nonhuman primates and demonstrate major evolutionary changes in the organization of the cortical aminergic input as compared with rodents. The most striking features are the expansion of the DA innervation to the whole cortex and the peak of highest density in the motor areas. The regional differentiation of NA innervation is also accentuated. Slight differences were found in the laminar distributions of the amines in humans and primates. These data seem quite promising and open new research fields in neurologic and psychiatric diseases.
Ventral mesencephalic neurons containing both cholecystokinin‐ and tyrosine hydroxylase‐like immunoreactivities project to forebrain regions
Authors: Seroogy Kim B. , Dangaran Karol , Lim Steven , Haycock John W. , Fallon James H. 
Published: January 2005

AbstractThe coexistence of cholecystokinin‐ and tyrosine hydroxylase‐like immunoreactivities within neurons of the rat ventral mesencephalon was analyzed by using an indirect immunofluorescence technique for the simultaneous demonstration of two antigens in the same tissue section. A high degree of colocalization was observed in the substantia nigra pars compacta, in which 80–90% of all labeled neurons at rostral and up to 70% at intermediate levels contained both cholecystokinin and tyrosine hydroxylase. At caudal levels, the incidence of colocalization declined to approximately 30–50%. All of the immunoreactive perikarya in the substantia nigra pars lateralis were labeled with both substances. Other areas of the ventral midbrain that exhibited a moderate proportion of neurons immunoreactive for both cholecystokinin and tyrosine hydroxylase included the ventral tegmental area, interfascicular nucleus, and rostral and caudal linear nuclei. In addition, coexistence was occasionally observed within neurons of the central and ventral periaqueductal gray matter, supramammillary region, peripeduncular region, retrorubral field, and, extremely rarely, within the substantia nigra pars reticulata. Cell bodies containing tyrosine hydroxylase‐like immunoreactivity (indicative of dopamine) usually outnumbered those containing the peptide except in the supramammillary region and in the ventral periaqueductal gray matter, where the cholecystokinin perikarya were present in higher numbers.The double‐labeling colocalization technique was combined with fluorescence retrograde tracing to determine some of the forebrain projections of these neurons. Ventral midbrain neurons containing both cholecystokinin and tyrosine hydroxylase were found to project to the caudate‐putamen, nucleus accumbens, prefrontal cortex, and amygdala. These projections originated from neurons located predominantly in the substantia nigra pars compacta and the ventral tegmental area. Thus, cholecystokinin occurs within the well‐known dopaminergic nigrostriatal pathway in the rat. Overall, these results demonstrate that a significant proportion of the dopamine neurons giving rise to the ascending mesotelencephalic projections also contain the peptide cholecystokinin.
Organization and synaptic interconnections of GABAergic and cholinergic elements in the rat amygdaloid nuclei: Single‐ and double‐ immunolabeling studies
Authors: Nitecka Liliana , Frotscher Michael 
Published: January 2005

AbstractThe aim of this study was to describe the localization of cholinergic and GABAergic neurons and terminals in the amygdaloid nuclei of the rat. Double immunolabeling was performed to study cholinergic‐GABAergic synaptic interconnections.Cholinergic elements were labeled by using a monoclonal antibody to choline acetyltransferase (ChAT), the acetylcholine synthesizing enzyme. Antibodies against glutamate decarboxylase (GAD), the GABA‐ synthesizing enzyme, were employed to identify GABAergic perikarya and terminals. The tissue sites of the antibody bindings were detected by using either Sternberger's peroxidase‐antiperoxidase (PAP) method or a biotinylated secondary antibody and avidinated ferritin. These two contrasting immunolabels allowed us to study GABAergic‐cholinergic interconnections at the electron microscopic level.Our study revealed a characteristic distribution of GABAergic and cholinergic elements in the various amygdaloid nuclei: 1) Large, ChATimmunopositive cells with heavily labeled dendrites were observed in the anterior amygdaloid area and in the lateral and medial zones of the central nucleus. These cells seem to constitute the intraamygdaloid extension of the magnocellular basal nucleus. Their dendrites invaded other amygdaloid nuclei, in particular the intercalated nuclei, the lateral olfactory tract nucleus, and the central zone of the central nucleus. These ChAT‐immunoreactive dendrites formed synaptic contacts with GAD‐positive terminals. GABAergic terminals probably thus exert an inhibitory amygdaloid influence onto cholinergic neurons of the magnocellular basal nucleus. 2) Two amygdaloid nuclei‐the basal dorsal nucleus and the lateral olfactory tract nucleus‐contained a dense network of ChAT‐immunoreactive fibers and terminals, but they also contained numerous GAD‐positive perikarya. Double‐immunolabeling experiments revealed cholinergic terminals forming synaptic contacts on GAD‐immunopositive cell bodies, dendritic shafts, and spines. 3) The central and medial nucleus seem to be the main target of GABAergic fibers to the amygdala. Both nuclei contained a dense plexus of GAD‐immunoreactive terminals that may arise, at least in part, from the GABAergic neurons in the basal dorsal nucleus. Inhibition of the centromedial “excitatory” region through intraamygdaloid GABAergic connections may reduce excitatory amygdaloid influence onto hypothalamus and brainstem.
Development of central projections of lumbosacral sensory neurons in the chick
Authors: Davis Brian M. , Frank Eric , Johnson Frances A. , Scott Sheryl A. 
Published: January 2005

AbstractThe development of central projections of sensory neurons in lumbosacral dorsal root ganglia (DRGs) was examined by using horseradish peroxidase labeling techniques in chick embryos from stage 23 (E4) to stage 39 (E13). Our results show that primary afferents reach the spinal cord by stage 23. Afferent axons extend in the primordium of the dorsal funiculus for several segments rostral and caudal to their segment of entry for over 24 hours before invading the gray matter at stage 28 (E6). Sensory fibers grow into the vicinity of motoneuron dendrites by stage 32 (E7.5), about the time that reflexes and apparent monosynaptic EPSPs can first be elicited. Dense projections into the dorsal laminae of the spinal cord, presumably representing cutaneous afferents, appear somewhat later, at about stage 39 (E13), when the segmental projection pattern begins to resemble the mature pattern.
Structure of the nucleus olfactorius anterior of the hedgehog (Erinaceus europaeus)
Authors: Valverde Facundo , López‐Mascaraque Laura , De Carlos Juan A. 
Published: January 2005

AbstractThe cytoarchitecture, topography, and cellular structure of the nucleus olfactorius anterior (NOA) in the hedgehog have been studied in Nissl‐stained and Golgi preparations. The NOA is an important receptive allocortical formation for olfactory fibers and the major source of association fibers relating the main olfactory bulb with the rest of the olfactory brain. It was divided into a bulbar part; four subdivisions named lateral, dorsal, medial, and ventral; an external part; and a posterior part. Except for the external and posterior subdivisions, the NOA is relatively homogeneous and, in spite of the apparent lack of sublamination in Niss‐stained material, four clearly defined cellular laminae were distinguished by the Golgi method. These layers were found to be strikingly similar to those in the piriform cortex. Layer I contains the terminal ramifications of apical dendrites of pyramidal cells and the collaterals of the lateral olfactory tract. The superficial part of layer II contains extraverted pyramidal cells with two or three apical dendrites ramifying in layer I. Most pyramidal cells in the deep part of layer II and layer III are typical pyramidal cells with axons entering the commissura anterior. Some pyramidal cell axons bifurcate into two branches running in opposite directions in the commissura anterior. The interstitial zone below layer III contains deep pyramidal cells and polymorphic cells with ascending branches. Cells with intrinsic axons were classified into four main categories according to the distribution of their axonal ramifications: (1) cells with very restricted axons, (2) cells with axons oriented tangentially in the superficial part of layer II, (3) cells with ascending axons located in the deep part, and (4) chandelierlike cells. Finally, some functional considerations are discussed.
Visual projections to the pontine nuclei in the rabbit: Orthograde and retrograde tracing studies with WGA‐HRP
Authors: Wells Graham R. , Hardiman Mervyn J. , Yeo Christopher H. 
Published: January 2005

AbstractVisual projections to the pontine nuclei in the rabbit were examined by means of both orthograde and retrograde tracing of WGA‐HRP. The tectopontine projection was examined following microinjections of WGA‐HRP in the right superior colliculus. The projection to the pontine nuclei is strictly ipsilateral and terminates at middle and caudal levels of the pons. The projection is absent in rostral pontine nuclei. The strongest projection is to the dorsal border of the dorsolateral pontine nuclei and is the only projection seen when the primary injection site is confined to superficial laminae. When the primary injection site also includes intermediate and deep laminae, patches of labelled terminals are also seen within dorsolateral, lateral, peduncular, paramedian, and ventral pontine nuclei as well as in the contralateral nucleus reticularis tegmenti pontis.The striate corticopontine projection was also examined with orthograde tracing of WGA‐HRP. The striate corticopontine projection is ipsilateral. Most labelled terminals were seen in dorsolateral and lateral pontine nuclei throughout the rostral half of pons with some additional terminal labelling in paramedian and peduncular nuclei. Labelled terminals were also seen in ventral pontine nuclei throughout the middle and caudal levels of the pons.In a retrograde tracing study, visual projections to the pontine nuclei were examined following microinjections of WGA‐HRP into the pontine nuclei. Labelled cells were seen ipsilaterally in superficial and deep laminae of the superior colliculus and in layer V of striate and surrounding occipital cortex. The pontine nuclei also receive ipsilateral projections from the ventral lateral geniculate, the nucleus of the optic tract, anterior and posterior pretectal nuclei, and the dorsal and medial terminal nuclei of the accessory optic system. These pathways are potential sources of visual input to the cerebellum.