bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological and functional changes in the retinotectal system of the pigeon during the early posthatching period
Authors: Bagnoli Paola , Porciatti Vittorio , Fontanesi Gigliola , Sebastiani Laura 
Published: January 2005

AbstractAnterograde transport of either HRP or wheat germ agglutinin‐conjugated HRP was used to study the posthatching development of the retinotectal connection in the pigeon. The functional maturation of the retinotectal system was also investigated by recording electroretinographic (ERG) and tectal evoked (TEP) responses to either flash or pattern stimuli. Two main morphological changes occurred in the retinotectal system during the first 6 days after hatching: (1) an ipsilateral retinofugal component that was present at hatching disappeared and (2) the outer tectal layers were progressively invaded by the contralateral retinofugal axons, which at hatching were limited to the stratum griseum et fibrosum superficiale of the dorsolateral tectal quadrant. During the early posthatching period, at the same developmental stage at which an ERG to unpatterned or patterned stimulation could first be recorded, a visually evoked response could be elicited in the contralateral optic tectum. Therefore, the retina and optic tectum seem to start functioning simultaneously, the limiting factor being the late maturation of photosensitive lamellae in the outer segments of the developing photoreceptors. During the first 20 days posthatching, the retinotectal system undergoes extensive development as revealed by latency and amplitude changes of the visually evoked potentials. We suggest that the pigeon visual system serves as a useful model for studies concerning visual development and plasticity.
Distribution of choline acetyltransferase‐immunoreactive neurons in the brain of a cyprinid teleost (Phoxinus phoxinus L.)
Authors: Ekström Peter 
Published: January 2005

AbstractThe distribution of putative cholinergic neurons in the brain of a cyprinid teleost was investigated by immunocytochemistry, with well‐characterized polyclonal antibodies to porcine choline acetyltransferase (ChAT), correlated with acetylcholinesterase (AChE) histochemistry. AChE‐positive neurons were more numerous than GhAT‐immunoreactive (ChAT‐IR) neurons. Regions with ChAT‐IR neurons generally also contained AChE‐positive ones, but regions with AChE‐positive neurons often did not contain (or contained only small numbers of) ChAT‐IR neurons. ChAT‐IR neurons were located in the brainstem cranial nerve motor nuclei, in the brainstem reticular formation, in the nucleus laterals valvulae and an adjacent subnucleus “a,” in the nucleus isthmi, and in the stratum griseum periventriculare of the tectum opticum. All neurons in these areas were AChE positive. ChAT‐IR neurons were also observed within the boundaries of the nucleus sensibilis nervi trigemini and the n. descendens nervi trigemini. The periventricular hypothalamus and the paraventricular organ, the pineal organ, and (possibly) the nucleus suprachiasmaticus also contained ChAT‐IR neurons. In these areas, AChE activity was either low or located mainly in neurons other than the ChAT‐IR ones. A small population of ChAT‐IR neurons was observed in area ventralis telencephali pars lateralis. This was the only telencephalic ChAT‐IR cell group. Furthermore, some previously unrecognized cell groups were observed. A small number of ChAT‐IR neurons, located on the dorsal aspect of the fasciculus longitudinalis medialis (caudal to n. raphe dorsalis), emitted axons that passed caudally along the raphe midline and innervated some of the large reticular neurons. Another group of ChAT‐IR neurons was observed caudal to the thalamic nucleus centralis posterior and was tentatively designed n. tractus rotundus, on the basis of the neuronal morphology. The almost Golgilike staining of some of the ChAT‐IR cell groups permitted the identification of their efferent connections and the areas covered by their dendrites.
Local circuit neurons of macaque monkey striate cortex: I. Neurons of laminae 4C and 5A
Authors: Lund Jennifer S. 
Published: January 2005

AbstractA study has been made, using Golgi preparations, of the organization of neurons with smooth or sparsely spined dendrites, here called local circuit neurons, of the macaque monkey primary visual cortex. Since these neurons include those responsible for inhibitory circuitry of the cortex, a better understanding of their anatomical organization is essential to concepts of functional organization of the region. This account describes those neurons found with cell body and major dendritic spread within the thalamic recipient zone of lamina 4C and its border zone with lamina 5A. The neurons are grouped firstly in terms of in which laminar division the soma occurred– 4CβbT, 4CβaL or the border zone of 5A‐4CβbT–and secondly, into varieties on the basis of the interlaminar projection patterns of their axons. Most, if not all, of the local circuit neurons of these divisions have interlaminar axon projections as well as an arbor local to their cell body and dendritic field. These interlaminar projections are highly specific, targeting from one to five laminar divisions depending on the variety of neuron; on this basis 17 varieties of local circuit neuron are described. While the number of varieties appears dauntingly large in terms of understanding the functional circuitry of the region, the clear‐cut organization of the interlaminar links may provide clues as to the information processing that concerns each neuron. The local circuit neuron axon projections can be related to a wealth of information already available concerning the laminar organization of afferent axons and efferent cell groups, the organization of spiny neuron intrinsic relays (presumed to be excitatory), and physiological properties of different laminar divisions. It is hoped that the information derived from this study can serve as a guide for correlated physiological‐anatomical studies on single cells of the region.
Vestibular nuclear complex in the guinea pig: A cytoarchitectonic study and map in three planes
Authors: Gstoettner W. , Burian M. 
Published: January 2005

AbstractCytoarchitectonic and fiberarchitectonic criteria were used in the preparation of a detailed map illustrating the vestibular nuclear complex of the guinea pig. The brainstems used for this study were serially cut at 16 μm in the transverse, the sagittal, or the horizontal plane. The sections were studied after being stained alternately with a combined cell and fiber staining method and a Nissl stain.The basic Cytoarchitectonic features of the four main vestibular nuclei, their extent, as well as their relationship to the surrounding structures are described. Additionally, the location, topographical features, and the cytoarchitecture of the small groups (f,g,l,x,y,z) associated with the vestibular nuclei are reported. Group f is especially well developed and easily distinguishable in the guinea pig. Furthermore, a hitherto undescribed cell cluster found dorsal to the dorsal border of the superior vestibular nucleus is presented. The results and especially the differences from the descriptions of other species are discussed.
A role of insular cortex in cardiovascular function
Authors: Ruggiero David A. , Mraovitch Sima , Granata Antonio R. , Anwar Muhammad , Reis Donald J. 
Published: January 2005

AbstractWe sought to determine whether the insular cortex contributes to the regulation of arterial blood pressure (AP). Responses to electrical and chemical stimulation of the cortex were studied in the anesthetized, paralyzed, and artificially ventilated Sprague‐Dawley rat. The insular cortex was initially defined, anatomically, by the distributions of retrogradely labeled perikarya following injections of wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) into the nucleus tractus solitarii (NTS). Injections of WGA‐HRP into the insular cortex anterogradely labeled terminals in cardiopulmonary and other divisions of the NTS and confirmed projections revealed by retrograde tracing experiments.Electrical stimulation of the insular cortex elicited elevations of AP (≤50 mm Hg) and cardioacceleration (≤ 40 bpm). The locations of the most active pressor sites corresponded closely to the locations of retrogradely labeled cells in layer V of granular and posterior agranular areas of the insular cortex (areas 14 and 13) and the extreme capsule. Maximal pressor responses were obtained at a stimulus intensity of three to five times threshold current of 20–30 μA. Responses elicited mostly with higher‐threshold currents were also mapped in areas 2a and 51b and the claustrum and within the corpus callosum. Unilateral injections into the insular pressor area of the excitatory amino acid monosodium glutamate (L‐Glu; 0.05 nmol to 10 nmol) or the rigid structural analogue of L‐Glu, kainic acid (KA) (0.4 nmol) (which specifically excite perikarya), caused topographically specific elevations in AP and tachycardia.During the course of the anatomical transport studies, new findings were obtained on the organization and characteristics of the cortical innervation of the NTS and the nucleus reticularis parvocellularis. Topographic relationships between the cortex and the NTS were organized in a more complex manner than previously thought. Cells projecting to caudal cardiopulmonary segments of the NTS were fewer and generally located ventrally and caudally and in a more restricted area than cells projecting rostrally or to the parvicellular reticular formation. Anterograde transport data revealed new presumptive terminal fields in dorsolateral, ventral, periventricular, and commissural regions of the NTS, including an area overlapping the terminal field of the aortic baroreceptor nerve.We conclude that (1) neurons within an area of the insular cortex projecting to multiple brainstem autonomic nuclei, including a region of the NTS innervated by baroreceptor afferents, increase arterial blood pressure and heart rate; (2) cortical projections to the NTS are widespread but limited to discrete subdivisions of the nucleus; (3) a comparatively small percentage of cortical neurons project to caudal versus rostra1 levels of the NTS; and (4) autonomic pathways from the insular cortex may regulate circulatory and possibly other autonomic functions.
Golgi analyses of dendritic organization among denervated olfactory bulb granule cells
Authors: Greer Charles A. 
Published: January 2005

AbstractIn the vertebrate olfactory bulb, the primary projection neurons, mitral and tufted cells, have reciprocal dendrodendritic synapses with respective subpopulations of anaxonic interneurons called granule cells. In the neurological murine mutant Purkinje Cell Degeneration (PCD) all mitral cells are lost during early adulthood. As a consequence, a subpopulation of granule cells is deprived of both afferent input and efferent targets. The effect of this event, on the morphology and sublaminar distribution of granule cells was studied with light microscopic Golgi procedures in affected homozygous recessive PCD mutants and normal heterozygous littermate controls. In the control mice, a minimum of three subpopulations were identified predominantly on the basis of the topology of apical dendrites and their spinous processes within the external plexiform layer (EPL) of the olfactory bulb: type I had dentrites extending across the full width of the EPL and a homogeneous distribution of spines; type II had dendritic arbors confined to the deeper EPL; type III had apical dendrites that arborized extensively within the superficial EPL with no arbors or spines present in the deeper EPL. Prior studies suggest that type II cells form connections with mitral cells; type III cells form connections with tufted cells; and type I cells may integrate information from both populations of projection neurons. In the mutant PCD mice, the classification of subpopulations of granule cells proved difficult due to a compression of dendritic arbors within the EPL. Dendritic processes followed a more horizontal tangent relative to the radial orientation seen in control mice. The length of dendritic branches was reduced by approximately 20% with a corresponding decrease in the number of spines. The density of spines ( #/1 m̈m of dendrite) was constant in both controls and mutants at approximately 0.21. Truncation of the dendrites in the PCD mutants appeared to occur at terminal portions because the number of dendritic bifurcations was equal in both groups of mice. The data are discussed in terms of subpopulations of granule cells in the mouse olfactory bulb, the sublaminar organization of olfactory bulb circuits, and the capacity for survival and plasticity in the reciprocal dendrodendritic circuits mediated by the granule cell spines.
Neurogenesis in the vocalization pathway of Xenopus laevis
Authors: Gorlick Dennis L. , Kelley Darcy B. 
Published: January 2005

AbstractWe examined possible contributions of neurogenesis to sex differences in the vocalization pathway of the South African clawed frog, Xenopus laevis. Birthdates of neurons were obtained from autoradiograms of animals receiving tritiated thymidine from gastrulation through 1 month after metamorphosis. Thymidine availability studies showed that 80% of the [3H]‐thymidine injected into embryos and tadpoles was incorporated into the DNA of dividing cells within 3 hours. We observed 3 patterns of neurogenesis: late‐short, a short burst of proliferation occurred late in development in the anterior preoptic area, the ventromedial nucleus of the thalamus, and the pretrigeminal nucleus of the dorsal tegmental area of the medulla; protracted‐bimodal, a prolonged period of proliferation with an early and a late peak in the number of labeled cells occurred in the ventral striatum and in the ventrolateral and posterior nuclei of the thalamus; protracted‐unimodal, a prolonged period of proliferation with a single early peak occurred in the inferior reticular formation and in the medial and lateral nucleus IX‐X (containing laryngeal motor neurons). There were no differences between sexes in the number of tritiated thymidine labeled cells in any nucleus. The difference in nucleus IX‐X neuron number in adults does not appear to result from sex differences in the proliferation of these cells during development. Since neurons in the vocalization pathway do not exhibit androgen receptors until after neurogenesis is complete, we also conclude that androgen probably does not regulate the genesis of these cells.
Spinocerebellar projections from the thoracic cord in the cat, as studied by anterograde transport of wheat germ agglutinin‐horseradish peroxidase
Authors: Yaginuma Hiroyuki , Matsushita Matsuo 
Published: January 2005

AbstractThe projection fields of the spinocerebellar tracts arising from thoracic segments were studied by the anterograde transport of wheat germ agglutinin bound to horseradish peroxidase (WGA‐HRP) in the cat.Following injections of WGA‐HRP into upper and middle thoracic segments, labeled mossy fiber terminals were seen in all lobules of the anterior lobe, lobules VI, VIII, and IX, sublobule VIIb, the paramedian lobule, medial parts of the dorsal paraflocculus, crus I, crus II, and the simple lobule. In the anterior lobe labeled terminals in sublobules IIb‐Vb accounted for about 50–60% of the total labeled terminals, of which about 14–18% were present in lobule III and 11–13% were present in lobule IV. The labeled terminals were concentrated within 1.0–1.5 mm from the midline in the vermal region, accounting for about 45–75% of the total in each sublobule. Following injections into lower thoracic segments, labeled terminals tended to distribute more numerously in the lateral part of the vermis and the intermediate region. In the posterior lobe about 5% of the total labeled terminals were distributed in lobules VI and VIII, respectively, and about 16–23% were in the paramedian lobule (mainly sublobules B and C). Cases with injections preceded by a lateral cordotomy have shown that about 65% of the total labeled terminals in each lobule of the anterior lobe were distributed ipsilaterally and 35%, contralaterally. In the paramedian lobule the labeled terminals were distributed predominantly ipsilaterally.Projection fields in the horizontal plane were reconstructed from a series of transverse sections through each lobule. In lobules III and IV the labeled terminals were distributed in nine areas: areas 1–4 in the vermis and areas 5–9 in the intermediate‐lateral regions. The two medial areas 1 and 2 were located within 0.5 mm from the midline in zone A1 of Voogd and area 3 appeared to be located in zone A2. Area 4 was located between 0.75 and 1.5 mm in the medial part of zone B. These areas extended longitudinally in the middle part of the apicobasal extent. The five areas in the intermediate‐lateral regions were localized in the basal part of the lobule: area 5 in zone C1, areas 6–8 in zones C2 and C3, and area 9 in zone D. Some of these projection areas were identified also in lobules I, II, and V. In sublobule Villa four distinct longitudinal areas containing labeled terminals were found in the middle part of the apicobasal extent. In the paramedian lobule labeled terminals were distributed in ill‐defined longitudinal areas in the medial and lateral parts of sublobules B (the posterior part) and C (the copular part).
Autoradiography of mossy fiber terminals in the fastigial nucleus of the cat
Authors: van der Want J. J. L. , Gerrits N. M. , Voogd J. 
Published: January 2005

AbstractTerminal boutons of mossy fiber collaterals in the fastigial nucleus originating from the nucleus reticularis tegmenti pontis, the bulbar reticular formation, and the medial vestibular nucleus were studied with high‐resolution autoradiography in order to examine their ultrastructural features and synaptic relations. Labeled mossy fiber boutons ranged in size from 0.5 to 5 μm in diameter, and they all contained clear and spherical vesicles in an electron‐lucent matrix, mitochondria, and some fine tubular elements. These boutons form asymmetric synapses with dendritic profiles of different sizes. No evidence was found for mossy fiber termination on the soma of fastigial neurons. Two types of mossy fiber terminals were distinguished on the basis of the aggregation of synaptic vesicles: one type with clustered vesicles and one type with densely packed vesicles, occurring in equal number from all sources. Furthermore, the applicability of the congruity hypothesis is confirmed for the general identification of terminals.
Displaced ganglion cells in the retina of the rat
Authors: Linden Rafael 
Published: January 2005

AbstractThe distribution, laterality of projection, and perikaryal sizes of displaced ganglion cells (DGCs) were examined in whole‐mounted retinae after massive unilateral injections of horseradish peroxidase along the optic tract in pigmented rats. The DGCs were found predominantly in the lower temporal periphery of the retina. Nearly all DGCs labeled had contralaterally projecting axons. The sizes of the labeled DGCs spanned the range of ordinary ganglion cells, but few middle‐sized DGCs were labeled. The results support the hypothesis that displaced ganglion cells are late‐developing neurons that do not complete their migration toward the ganglion cell layer during retinal histogenesis.
Transneuronal transport of wheat germ agglutinin‐conjugated horseradish peroxidase into trigeminal interneurones of the rat
Authors: Appenteng K. , Girdlestone D. 
Published: January 2005

AbstractIntramuscular injections of either horseradish peroxidase (HRP) or wheat germ agglutinin‐conjugated horseradish peroxidase (WGA‐HRP) were made into the masseter muscle of rats. Both tracers labeled primary sensory neurones in the V mesencephalic nucleus, motoneurones in the V motor nucleus, and some motoneurones in die facial motor nucleus. WGA‐HRP labeled additional neurones in the V main sensory nucleus and the rostral pole of the V nucleus oralis. These were classed as interneurones because they lay in areas outside those known to contain either first‐order afferent or motoneurone somata. We argue that these were labeled by retrograde transport of tracer because they lay close to the V motor nucleus, and from some of them processes could be followed into the region of the V motor nucleus.
The connection of the peripeduncular area studied by retrograde and anterograde transport in the rat
Authors: Arnault Patricia , Roger Michel 
Published: January 2005

AbstractLying just ventral to the medial geniculate nucleus and dorsal to the cereberal peduncle, the peripeduncular area (PPA) seems to be implicated in the expression of several sexual reflexes in rodents. The aim of the present investigation was to establish the organization of the afferent and efferent projections of the rat's PPA in an attempt to provide a neural substrate corresponding to the behavioral observations. Based on both retrograde and anterograde transport methods, our results suggest that the PPA: (1) receives its main afferent projections from the insulotemporal cortex, basal ganglia, ventromedial and posterior hypothalamic nuclei, zona incerta, inferior colliculus, intermediate and deep layers of the superior colliculus, central gray, cuneiform nucleus, laterodorsal tegmental nucleus, and dorsal nucleus of the lateral leminiscus and, (2) projects essentially to the basal ganglia, ventromedial hypothalamic nucleus, central gray, cuneiform and pedunculopontine nuclei, deep layers of the superior collic‐ulus, inferior colliculus, and dorsal and ventral nuclei of the lateral lemniscus. These findings, indicating that the PPA is connected with the auditorry, motor, and limbic systems and with nonspecific diencephalic and mesencephalic centers, are in agreement with the notion that in rodents this area might play a role in the female sexual receptivity (as expressed by lordosis display or ultrasound production) or male mounting behavior.