bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organization of the spinocervicothalamic pathway in the rat
Authors: Giesler G. J. , Björkeland M. , Xu Q. , Grant G. 
Published: January 2005

AbstractWe used silver degeneration techniques to examine the termination of the spinocervical and cervicothalamic tracts in rats. Lesions of the dorsal portion of the lateral funiculus (DLF) of the spinal cord produced degeneration of a relatively small number of ascending fibers that were seen within the most lateral portion of the DLF rostral to the lesion. Within the lateral cervical nucleus, the degeneration was more extensive mediolaterally and of a finer caliber. Such labeling is attributable to the degeneration of fine fibers and terminals. Degenerating processes could be seen in apposition to neurons in the lateral cervical nucleus. At all levels of the cord, the lateral spinal nucleus was devoid of terminal labeling following lesions of the DLF. No terminal degeneration could be seen within the DLF at levels rostral to the lateral cervical nucleus. Lesions of the DLF at either midcervical or lower thoracic levels produced degeneration throughout the lateral cervical nucleus. This finding suggests that the lateral cervical nucleus of the rat is not somatotopically organized.Lesions of the lateral cervical nucleus produced degeneration of a small number of fibers within the contralateral midbrain and thalamus. Within the mesencephalon, degenerating fibers and terminals were seen primarily in the intercollicular region and the deep layers of the superior colliculus. Less degeneration was found in the lateral portion of the central gray. Within the diencephalon, a small area of termination was located in the ventromedial part of the rostral portion of the medial geniculate nucleus. A prominent termination was present in a restricted area within the caudal fourth of the ventrobasal complex.
Mesodiencephalic projections to the vestibular complex in the cat
Authors: Spence Sandra J. , Saint‐Cyr Jean A. 
Published: January 2005

AbstractThe distribution of cells in the rostral medial mesencephalon and caudal diencephalon which project to the vestibular complex was mapped in the cat by using retrograde axonal transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP). Subsequent experiments using anterograde transport of WGA‐HRP clarified the position of the terminations of the mesodiencephalic‐derived afferents in the vestibular complex.After large injections which involved the entire vestibular complex, retrogradely labeled cells were seen in both the ipsilateral and contralateral interstitial nucleus of Cajal (INC) and were more numerous in its rostral pole. Labeled cells also occurred in the perifascicular region, both immediately adjacent to the fasciculus retroflexus and rostroventral to it. Fusiform midline cells of the Edinger‐Westphal nucleus were also labeled, as well as a number of cells in the adjacent somatic portion of the oculomotor complex (OMC). Another group of labeled cells was observed within the contralateral medial terminal nucleus of the accessory optic tract (MTN) and in the posterior hypothalamic nucleus. Injections limited to subregions of the vestibular complex resulted in similar but slightly varying distributions and numbers of retrogradely labeled cells. After injections covering the caudal half of the medial vestibular nucleus (MVN) and descending vestibular nucleus (DVN), labeled cells in the INC and tegmentum dorsal to it were especially prominent, but none was seen in the MTN or OMC. Injections placed in the rostral MVN, lateral vestibular nucleus, y group, and superior vestibular nucleus resulted in a distribution of labeled cells similar to that seen following global vestibular injections, but these cells were fewer in number. After an injection confined to the y group, a small number of retrogradely labeled cells were seen in the rostral pole of the INC and immediately ventral to the fasciculus retroflexus.Projections from the rostral medial mesencephalon and caudal diencephalon to the MVN, DVN, and y group were confirmed by using anterograde transport of WGA‐HRP.Direct projections from the INC‐perifascicular regions and somatic neurons of the OMC to the caudal vestibular complex could play a role in eye‐head coordination. Those projections from the rostral INC and MTN to the rostral vestibular complex may play a role in vertical eye movements and responses to visual stimuli which move in the vertical plane.
Retinal projections to the pretectum in the pigeon (columba livia)
Authors: Gamlin Paul D. R. , Cohen David H. 
Published: January 2005

AbstractThe retinal projection to the pretectum in the pigeon has previously been described in detail only by means of anterograde degeneration techniques (Repérant, '73). The present study reinvestigated these retinal projections by using the more sensitive anterograde autoradiographic technique. In general, our results confirm and extend those of Repérant ('73). We have found that three pretectal nuclei–the nucleus lentiformis mesencephali, tectal gray, and the area pretectalis– receive heavy retinal input. A fourth pretectal nucleus, pretectalis diffusus, receives a slight retinal input. The nucleus lentiformis mesencephali can be divided into two closely apposed subnuclei that are cytoarchitecturally similar. We have termed them “lentiformis mesencephali, pars medialis” and “lentiformis mesencephali, pars lateralis.” The tectal gray can be divided into a rostral, retinorecipient region and a narrow, caudal, nonretinorecipient region. The cytoarchitecture and retinal terminal field in area pretectalis have been described previously by us (Gamlin et al., '84). Pretectalis diffusus is located caudal to the retinorecipient dorsal thalamus and rostral to area pretectalis.Localized retinal injections of 3H proline delineated the number and extent of the retinal representations in the pretectum. Separate retinal representations were present in lentiformis mesencephali, pars medialis, lentiformis mesencephali, pars lateralis, the tectal gray, area pretectalis, and pretectalis diffusus. Only in the lentiformis mesencephali, pars medialis, lentiformis mesencephali, pars lateralis, and the tectal gray could the retinal representations be analyzed. Whereas the retinal representations in the lentiformis mesencephali, pars medialis and the tectal gray are comparable, the retinal representation in the lentiformis mesencephali, pars lateralis is different, being a mirror‐image mediolaterally.In this study we introduce a conservative nomenclature for the retinorecipient pretectal nuclei that is consistent with earlier studies, in particular, those of Kuhlenbeck ('39), but has been modified in the light of our findings. We believe that this nomenclature, combined with the detailed cytoarchitectural descriptions provided, should facilitate future studies of the avian pretectum.
Catecholaminergic subpopulation of retinal displaced ganglion cells projects to the accessory optic nucleus in the pigeon (Columba livia)
Authors: Britto Luiz R. G. , Keyser Kent T. , Hamassaki Dania E. , Karten Harvey J. 
Published: January 2005

AbstractIn birds, displaced ganglion cells (DGCs) constitute the exclusive source of retinal input to the nucleus of the basal optic root (nBOR) of the accessory optic system. Tyrosine‐hydroxylase (TH) immunoreactivity was examined in the pigeon retina after injections of rhodamine‐labeled microspheres into the nBOR. A population of about 400 DGCs was observed in each case to exhibit both TH immunoreactivity and rhodamine bead fluorescence. This corresponded to about 10–15% of the total number of identified DGCs in each retina. Double‐labeled cells were medium‐ to large‐size (12 to 20 μm in the largest axis) and were always located at the border between the inner nuclear and the inner plexiform layers. Their dendrites could be followed horizontally in lamina 1 of the inner plexiform layer for up to 300 μm from the cell body. The distribution of double‐labeled DGCs appeared to be mostly peripheral, matching the overall distribution of identified DGCs. Larger DGCs (21–28 μm) were never seen to contain TH immunoreactivity. Examination of brain sections revealed plexuses of thin varicose TH‐positive axons in all subdivisions of the nBOR. Unilateral enucleation produced an almost complete elimination of TH immunoreactivity in the contralateral nucleus. Such results suggest the existence of a population of catecholaminergic DGCs projecting into the accessory optic system of the pigeon. They also support the emerging hypothesis concerning the neurotransmitter heterogeneity of ganglion cells in the vertebrate retina.
Postembryonic development of the dorsal ocellus of the american cockroach
Authors: Toh Yoshihiro , Yokohari Fumio 
Published: January 2005

AbstractPostembryonic development of the dorsal ocellus of the cockroach Periplaneta americana was examined. Small ocelli (20 μm in diameter) with less than 100 cells in the newly hatched nymph become adult ocelli (more than 500 μm in diameter) with more than 10,000 retinular cells, through ten to 11 nymphal stages. Thus, sequential steps of morphogenesis of rhabdomeres from loose interdigitations of apposed cell membranes to regularly arranged microvilli can be seen in the nymphal ocelli. Some retinular axons appear to extend into the brain as a bundle in the first‐instar nymph. Retinular axons differentiated later also extend toward the brain, but there is no evidence that they enter it. The ultrastructure of the ocellus and component analysis of the ocellar electroretinogram suggest that functional connections between retinular axons and ocellar interneurons do not occur in the ocellar capsule until mid (the fifth or sixth)‐instar nymphs. The ocellar diameter increases linearly with increase in body length during the nymphal stages, but it increases by a factor of 1.5–2.0 during the final molting: the body length of the adult is almost the same as that of the last‐instar nymph. These data suggest that the function of the dorsal ocelli may be closely related to specific adult behavior such as flight.
Patchy intrinsic projections in visual cortex, area 18, of the cat: Morphological and immunocytochemical evidence for an excitatory function
Authors: LeVay Simon 
Published: January 2005

AbstractSmall injections of peroxidase‐labeled wheat germ agglutinin into cat area 18 gave rise to patches of labeled cells and axon terminals around the injection site. In EM sections it was found that the labeled cells had a pattern of synaptic inputs characteristic of spiny‐dendrite neurons (pyramidal or spiny stellate cells). The labeled axon terminals formed type 1 (asymmetric) synapses, most of which were made onto dendritic spines. In other experiments injections of fluorescent beads were made into area 18, giving rise to a similar patchy distribution of labeled cells. The sections were then processed for immunocytochemical demonstration of γ‐aminobutyric acid (GABA). The bead‐labeled cells in the patches were GABA negative. The findings suggest that the patchy projections mediate mutual excitation between groups of spiny‐dendrite neurons.
Distribution of cholecystokinin‐immunoreactive cell bodies in the male and female rat: II. Bed nucleus of the stria terminalis and amygdala
Authors: Micevych Paul , Akesson Thomas , Elde Robert 
Published: January 2005

AbstractThe distribution of cholecystokinin‐immunoreactive (CCK‐I) cell bodies was studied in the bed nucleus of the stria terminalis (BST) and amygdaloid complex of colchicine‐treated male and female rats. Immunoreactive cells were visualized in the BST medial amygdaloid (MeA), central lateral, basolateral, basolateral ventral, medial, intercalated, anterior cortical, and posterior cortical nuclei and the amygdalohippocampal zone. Several significant sex differences were observed. In the male, a dense aggregation of CCK‐I cell bodies was visualized in the MeA, especially in the dorsocaudal part and in the encapsulated part of the BST. In comparison, female rats had relatively fewer immunoreactive cells in both of these regions. In the lateral and basolateral amygdaloid nuclei, however, more CCK‐I cells were visualized in the female than in the male, but the difference was not statistically significant. These data provide characterization of a sexually differentiated CCK system. In addition, we observed that the number of CCK‐I cells in the BST and posterodorsal part of the MeA was substantially reduced after castration. The number of CCK‐I cells in female rats, however, was not significantly reduced after ovariectomy in any of the regions studied. These findings imply that the steroid regulation of CCK is sexually differentiated. The sexually dimorphic distribution of CCK‐I cells in areas that are targets of steroid hormones and regulate reproductive processes is consistent with the possibility that CCK participates in central integration of sensory and steroidal input that modulates reproductive behavior.
Ultrastructure of mouse vallate taste buds: III. Patterns of synaptic connectivity
Authors: Kinnamon John C. , Sherman Terri A. , Roper Stephen D. 
Published: January 2005

AbstractWe have used serial high voltage electron micrographs and computergenerated, three‐dimensional reconstructions to study morphological relationships and patterns of synaptic connectivity in taste buds from the circumvallate papillae of the mouse.The intragemmal arborizations of 40 sensory nerve fibers were examined from 7 taste buds that were sectioned serially. We identified the synaptic connections from taste cells onto the reconstructed nerve fibers and classified the presynaptic taste cells based on previously established ultrastructural criteria. From these data we were able to extract the following information for the reconstructed nerve fibers: (1) the morphology of intragemmal nerve fibers and their arborizations within the taste bud, (2) the total number of synaptic connections from taste bud cells onto the nerve fibers, and (3) the taste cell types associated with each of the synapses.Fifty‐six synapses were studied. Synapses were often found to be located at either the branch points or terminations of nerve fiber processes. The maximum number of taste cells observed to synapse onto a single nerve fiber was 5. Several nerve fibers had no apparent synapses. Dark cells (type I), intermediate cells, and light cells (type II) all formed synaptic connections with sensory nerve fibers. In no cases did dark cells and light cells synapse onto the same sensory nerve fiber. Our observation that any given nerve fiber receives its synaptic input from morphologically similar taste cells provides evidence for specificity in taste bud synaptic connections. We speculate that the observed pattern of synaptic connections is related to taste bud function. Since all of the synapses onto a given nerve fiber are from morphologically similar taste cells, we postulate that there is a correlation between taste cell morphology and sensory responsiveness. Intracellular electrophysiological studies on taste cells, in which responses to focally applied chemical stimuli are followed by characterization of the ultrastructural features of the same taste cells, will prove or disprove this hypothesis.
Axonal domains within shared touch domes in the rat: A comparison of their fate during conditions favoring collateral sprouting and following axonal regeneration
Authors: Yasargil G. M. , Macintyre L. , Doucette R. , Visheau B. , Holmes M. , Diamond J. 
Published: January 2005

AbstractLow‐threshold mechanosensory nerves in the adult rat differ both from their counterparts in lower vertebrates and from high‐threshold nociceptive nerves in mammals in that they appear not to undergo collateral sprouting into adjacent denervated skin, although they will clearly regenerate into it after they are damaged. We have now studied the growth capabilities of the low‐threshold nerves supplying touch domes, the visible mechanosensory structures scattered throughout the hairy skin. Touch domes in the rat are often multiply innervated. A serendipitous observation on such domes allowed us to investigate the possibility that a functional collateral sprouting of their nerves can indeed occur, but only to a spatially very restricted extent, e.g., within the confines of a partially denervated dome. We used a “prodder” with a tip diameter of 16 μm to examine the mechanosensory profile across single domes that were preselected as being supplied by only two axons, one running in each of two adjacent dorsal cutaneous nerves (DCNs). Simultaneous recordings were made of the afferent discharges evoked in these nerves when the prodder was applied at about 17 or more locations on a selected dome; the spatial resolution was better than 55 μm. We found that within such a shared dome, one axon can supply a discrete territory (its “domain”), which may or may not overlap with the corresponding domain of the other axon. In a preliminary electron microscopic study, we found no evidence for a sharing of single Merkel cells, which are the specialized sensory cells in touch domes, even in the regions of a shared dome where two domains overlapped; each innervated Merkel cell appeared to be contacted by a single nerve ending, implying that in a shared dome each axon probably supplies an exclusive subpopulation of the Merkel cells. We tested for functional collateral sprouting by eliminating one nerve to a shared dome, and at a selected time thereafter mapping the domain of the remaining axon to see whether it had enlarged. The result was the same whether the two domains initially had a region of overlap or not; no expansion of the surviving domain occurred over postoperative periods up to 4 months (an expansion of the domain by 55 μm would have been detected). Thus functional collateral sprouting had failed to occur. In contrast, when the entire DCN containing one of the axons was surgically eliminated, and that containing the other axon crushed and allowed to regenerate, invariably the axon that grew into the now totally denervated dome invaded it extensively, restoring mechanosensitivity to both former domains.The likelihood that these and related results imply that collateral sprouting and regeneration are evoked by different mechanisms is discussed.
Localization of angiotensin II receptor binding in rabbit brain by in vitro autoradiography
Authors: Mendelsohn F. A. O. , Allen A. M. , Clevers J. , Denton D. A. , Tarjan E. , McKinley M. J. 
Published: January 2005

AbstractBinding of 125I‐[Sar1, Ile8] angiotensin II (AII) to sections of brains from both wild and laboratory rabbits was determined by in vitro autoradiography. In the forebrain, specific high density binding was observed in the olfactory bulb, organum vasculosum of the lamina terminalis (OVLT), subfornical organ, median eminence, lateral septum, median preoptic nucleus and hypothalamic paraventricular, supraoptic and arcuate nuclei. In the midbrain, binding of the radioligand was observed in the interpeduncular and parabrachial nuclei, in the locus coeruleus, and ventrolateral pons. In the hind brain, there was dense binding of 125I‐[Sar1,Ile8] All to the nucleus of the solitary tract (NTS) and to both rostral and caudal parts of the reticular formation of the ventrolateral medulla oblongata. Weaker specific binding of the radioligand to the molecular layer of the cerebellum, to the nucleus of the spinal trigeminal tract, dorsal motor nucleus of the vagus, area postema, and to a band of tissue connecting the NTS to the ventrolateral medulla was also observed. Binding of the ligand to circumventricular organs such as the OVLT, subfornical organ, and median eminence suggests that these are sites in the brain of the rabbit at which blood‐borne All may exert influences on the central regulation of fluid balance and pituitary hormone secretion, although All of neuronal origin could also act at these sites. Binding of the radioligand in several other brain regions suggests that angiotensin II of cerebral origin may be involved in a number of different aspects of brain function in the rabbit. The finding of dense binding in the NTS and ventrolateral medulla, which are involved in autonomic activity and are also sites of catecholamine‐containing neurons, raises the possibility of angiotensin interaction with these neurons and involvement in autonomic function.
Corticotropin releasing factor‐containing afferents to the lateral septum of the rat brain
Authors: Sakanaka Masahiro , Magari Sumiko , Shibasaki Tamotsu , Lederis Karl 
Published: January 2005

AbstractCorticotropin releasing factor (CRF)‐containing afferents to the rat lateral septum (LS) have been determined by means of cobalt‐enhanced immunohistochemistry, tracing of retrograde transport of horseradish peroxidase (HRP), and by lesioning experiments.When unilateral lesions included the rostral part of the hypothalamus, CRF‐like immunoreactive (CRFI) ipsilateral fibers in the LS decreased in number. Lesions in other brain regions did not cause alterations in the septal CRFI fibers. These findings suggest that the septal CRFI fibers originate in the rostral part of the hypothalamus. Furthermore, combined HRP and immunohistochemical staining cm the same sections demonstrated double‐labeled cells in two discrete areas within the rostral hypothalamus: one was the perifornical hypothalamic area (PeF) at the level of the paraventricular hypothalamic nucleus, and the other was the most caudal part of the anterior hypothalamic nucleus (AHc). These findings show that a large proportion of the CRFI projections to the LS have their origins in the PeF and AHc.
Neurons containing calcitonin gene‐related peptide in the parabrachial nucleus project to the central nucleus of the amygdala
Authors: Schwaber J. S. , Sternini C. , Brecha N. C. , Rogers W. T. , Card J. P. 
Published: January 2005

AbstractThe source, distribution, and morphology of axons displaying calcitonin gene‐related peptide (CGRP) immunoreactivity in the central amygdaloid nucleus of the adult rat were investigated with immunohistochemical techniques, both alone and in combination with retrograde transport of fluorescent tracers. An extremely dense plexus of CGRP‐immunoreactive axons is differentially concentrated within the lateral capsular and lateral central subdivisions of the central nucleus, and much lighter concentrations of labeled fibers are present in the rostral part of the medial subdivision. No immunoreactive neurons were observed in the central nucleus in any of the experimental animals. The immunoreactive axons characteristically form prominent pericellular terminal arborizations surrounding unlabeled neurons. The number of cells receiving this dense input increases at caudal levels of the central nucleus. Retrograde label of central nucleus neurons by dye transport from injections into the pontine parabrachial nucleus and the nucleus of the tractus solitarius combined with CGRP immunohistochemistry established that many neurons in the central nucleus which receive dense pericellular innervation from CGRP‐immunoreactive axons are projecting caudally to the parabrachial nucleus or, to a lesser extent, to the nucleus tractus solitarii. Central amygdaloid injections of rhodamine‐labeled microspheres or fluorogold followed by immunohistochemical localization of cellular CGRP immunoreactivity revealed that the central amygdaloid CGRP fiber plexus originates bilaterally from the parabrachial nucleus. These multipolar CGRP‐containing neurons are preferentially concentrated in the external medial and external lateral subnuclei, in the ventral aspect of the parabrachial nucleus. These results relating central amygdaloid CGRP to ascending and descending brainstem pathways, taken together with the extreme density of the fiber plexus, strongly suggest the relevance of the CGRP input to central nucleus function in cardiovascular and other autonomic regulation.