bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substance P‐ and opioid‐immunoreactive structures in olfactory centers of the cat: Adult pattern and postnatal development
Authors: Wahle Petra , Sanides‐Kohlrausch Claudia , Meyer Gundela , Lubke Joachim 
Published: May 2005

AbstractSubstance P (SP)‐ir and opioid‐ir structures were studied in the cat main olfactory bulb (MOB), accessory olfactory bulb (AOB), and olfactory peduncle. In the MOB, the opioid‐ir and the majority of the SP‐ir neurons belong to the granule cell type. SP‐ir granule cells reside in the deeper granule cell layer, whereas opioid‐ir granule cells reside in the superficial granule cell layer, internal plexiform, and mitral cell layer. Many granule cells are observed in the external plexiform and glomerular layer. Other granule cells were found in the bulbar/peduncular white matter, the taenia tecta, and the genu of the corpus callosum. A new substance P‐ir cell type was identified in the glomerular layer. This cell type was also identified by using the technique of intracellular injection of Lucifer Yellow. The cell type corresponds neither to the external tufted type nor to the short axon cell types described so far.The AOB resembles the MOB with respect to large numbers of SP‐ir and opioid‐ir granule cells. In addition, a few opioid‐ir neurons, probably superficial mitral cells, were found in the glomerular layer. The AOB is surrounded by islands of immunoreactive granule cells, which connect to the granule cell layer by extremely long processes.Opioid‐ir and SP‐ir beaded axons pass through the olfactory peduncle terminating on granule cells, and ascend as far as the glomerular layer. All subdivisions of the anterior olfactory nucleus (AON) contain immunoreactive terminal fields. Afferent fibers and terminal plexuses derive from a population of immunoreactive neurons located predominantly in the region of the septo‐olfactory junction. They have large somata. Their axons form recurrent collaterals, some of which run rostrally in the peduncular white matter. Others ascend caudally towards the septal region. The fibers seem to remain ipsilaterally, since the olfactory limb of the anterior commissure and the commissure proper are devoid of SP‐ir and opioid‐ir fibers.During development SP and opioid immunoreactivity were found only in differentiated granule cells. The peptides were not detectable in migrating or immature granule cells, as identified in Golgi‐impregnated material. The granule cell population largely develops during postnatal life. The number of opioid‐ir granule cells increases slowly and continuously, reaching the adult level not before the sixth postnatal month. Strikingly, SP‐ir granule cell number increases fast and reaches a transient peak during the second month. Thereafter it declines (40% decrease) to the adult density, which is similar to that of opioid‐ir granule cells.
Macaque accessory optic system: I. Definition of the medial terminal nucleus
Authors: Cooper Howard M. , Baleydier Christine , Magnin Michel 
Published: May 2005

AbstractThe organization of the accessory optic system (AOS) has been studied in the macaque monkey following intravitreal injections of tritiated amino acids in one eye. Retinal projections to the dorsal (DTN) and the lateral (LTN) terminal nuclei are identical to those previously described in other primate species. We observed an additional group of retinorecipient cells of the AOS, located between the cerebral peduncle and the substantia nigra, which we define as the interstitial nucleus of the superior fasciculus, medial fibers. In this report, we focus our attention on the medial terminal nucleus (MTN). Although a ventral division of this nucleus (MTNv) was not observed in the macaque, the retina projects to a group of cells in the midbrain reticular formation (MRF), which we argue to be homologous to the dorsal division of the MTN (MTNd). To provide evidence in support of this homology, the retinal projection to the MTNv and MTNd was also examined in 21 additional species from 11 orders of mammals including carnivores, marsupials, lagomorphs, rodents, bats, insectivores, tree shrews, hyraxes, pholidotess, edentates, and five additional species of primates. Whereas the retina projects to both ventral and dorsal divisions in all species studied, in haplorhine primates only the projection to the MTNd is conserved. The relative topological position of the MTNd in the MRF, dorsomedial to the substantia nigra and ventrolateral to the red nucleus, remains constant throughout the mammals. The trajectory of fiber paths innervating the MTNd is also similar in all species. In addition, the MTNd has comparable afferent and efferent connections with retina, pretectum, and vestibular nuclei in all species thus far studied. These results support the unequivocal conclusion that the MTNd is an unvarying feature of the mammalian AOS.
Macaque accessory optic system: II. Connections with the pretectum
Authors: Baleydier Christine , Magnin Michel , Cooper Howard M. 
Published: May 2005

AbstractConnections of the accessory optic system (AOS) with the pretectum are described in the macaque monkey. Injections of tritiated amino acids in the pretectum demonstrate a major contralateral projection to the dorsal (DTN), lateral (LTN), and medial (MTN) terminal nuclei of the AOS and a sparser projection to the ipsilateral LTN. Injections of retrograde tracers, Fast Blue (FB), or wheat germ agglutinin horseradish peroxidase (WGA‐HRP) plus nonconjugated horseradish peroxidase (HRP) in the LTN show that the pretectal‐LTN projection originates from two nuclei. The main source of pretectal efferents to the LTN is from the pretectal olivary nucleus (OPN) and is entirely contralateral. This projection, which appears unique to primates, originates from the large multipolar cells of the OPN. In addition to this projection, the nucleus of the optic tract (NOT) projects to the ipsilateral LTN, as in nonprimates. Injection of WGA‐HRP in the pretectum shows a reciprocal predominantely ipsilateral projection from the LTN to the pretectum.Retinas were observed after injection of FB in the LTN. The retinal ganglion cells projecting to the AOS are mainly distributed near the fovea and in the nasal region of the contralateral eye, suggesting a nasotemporal pattern of decussation.The demonstration of a direct connection between LTN and OPN forces to a reconsideration of the functional role of the AOS. Previous descriptions of luminance responsive cells in the LTN support a possible participation of this nucleus in the control of the pupillary light reflex.
Multiple representations of body movements in mesial area 6 and the adjacent cingulate cortex: An intracortical microstimulation study in the macaque monkey
Authors: Luppino G. , Matelli M. , Camarda R. M. , Gallese V. , Rizzolatti G. 
Published: May 2005

AbstractThe mesial agranular frontal cortex that lies rostral to area 4 (F1) is formed by two distinct cytoarchitectonic areas: F3, located caudally, and F6, located rostrally. In the present experiments we investigated the organization of F3 and F6 by observing the motor responses evoked by their intracortical electrical microstimulation. Our main purpose was to find out whether the cytoarchitectonic subdivision of the mesial agranular frontal cortex into two areas has a physiological counterpart.The result showed that F3 (the caudal area) contains a complete motor representation with hindlimb movements located caudally, forelimb movements located centrally, and orofacial movements located rostrally. The great majority of limb movements involved proximal joints. With respect to F1, F3 showed the following functional characteristics: (1) lack of segregation between proximal and distal movements, (2) larger percentage of complex movements, and (3) higher excitability threshold.Movements were more difficult to elicit from F6 (the rostral area) than from F3. However, by using a longer stimulus train duration (100 ms) 39.3% of tested sites produced body movements. This percentage increased (50.5%) when the electrical stimulation was applied during monkey natural movements instead of when the monkey was still in its chair. Most of the evoked movements concerned the forelimb. More rarely, neck and upper face movements were observed. Unlike F1 and F3 where most movements were fast, slow movements were frequently observed with stimulation of F6. Many of them mimicked natural movements of the animal. Eye movements were evoked from F7 (superior area 6) but not from F6.An additional motor representation was found in the dorsocaudal part of area 24 (24d). This area is topographically organized with a forelimb representation located caudally and ventrally and a hindlimb representation located rostrally and dorsally. The excitability threshold of area 24d is higher than that of F1 and F3. Evoked movements were occasionally observed also after stimulation of area 24c.In conclusion, on the mesial cortical wall rostral to F1, there are at least three independent motor representations. On the basis of somatotopic organization and excitability properties, we propose that the term supplementary motor area (SMA‐proper) should be reserved to F3.
Visuotopic organization of corticocortical connections in the visual system of the cat
Authors: Salin P. A. , Girard P. , Kennedy H. , Bullier J. 
Published: May 2005

AbstractIt has recently been demonstrated that, in contrast with the retinogeniculocortical projection, the corticocortical connections in the cat present a high degree of convergence and divergence. This suggests that some corticocortical connections link nonvisuotopically corresponding regions. Using fine‐grain electrophysiological mapping and anatomical tracing, we have set out to test this possibility by placing a small injection of retrograde tracer in area 17 and by comparing the extent of visual field encoded in the region of area 18 containing labeled cells and that represented in the uptake zone.The results demonstrate that the size of the labeled region on the surface of area 18 is independent of eccentricity and that, despite its anisotrophy, this region of labeling encodes a broadly circular region of visual field that is larger than that encoded in the uptake zone of the tracer in area 17. For example, in the representation of lower visual field, a virtual point in area 17 that encodes a visual field region 4° in diameter receives afferents from a region of area 18 encoding a region 11° wide. Examination of the density of labeled cells in the labeled zone in area 18 reveals that the highest density is observed in a region in visuotopic correspondence with the injection site. However, high labeling density is also occasionally found in patches that do not represent the same visual field region as the injection site. Many receptive fields of neurons recorded in the labeled zone in area 18 only partially overlap or fail to overlap the visual field region encoded by the injection site.The results also demonstrate that the extent of visual field encoded in the labeled zone in area 18 is the same as that represented in the region of intrinsic labeling in area 17. It is suggested that cortical afferents coming from several cortical areas and converging on a column of cells in area 17 cover the same extent of visual field and that this cortical network constitutes the structural basis for the modulatory regions of the receptive field as well as the synchronization of neurons in different cortical areas.
Light‐dependent plasticity of the synaptic terminals of Mb bipolar cells in goldfish retina
Authors: Yazulla Stephen , Studholme Keith M. 
Published: May 2005

AbstractWe recently described spine‐like protrusions (spinules) from the synaptic terminals of mixed rod‐cone (Mb) bipolar cells of goldfish retina that invaginated about 5% of the presynaptic amacrine cell processes (Yazulla and Studholme, J Comp Neurol 310:11, 1991). In view of reports of a light/dark dependent‐plasticity on the formation of dendritic spinules on goldfish horizontal cells (Raynauld et al., Science 204:1436, 1979; Wagner, J Neurocytol 9:573, 1980), we investigated the possibility that Mb terminal spinules also might show light/dark‐dependent plasticity. Retinas were obtained at noon time from light‐adapted and 3‐hour dark‐adapted goldfish and processed for electron microscopy using conventional histological procedures and by preembedding immunocytochemistry to detect protein kinase C immunoreactivity. Two effects of light adaptation on Mb terminal morphology were observed. First, the surface of Mb terminals was significantly more irregular after dark adaptation than light adaptation. With dark adaptation, Mb terminals appeared «amoeboid,» with numerous cytoplasmic extensions between the presynaptic processes. Second, spinules were sevenfold more frequent after dark adaptation than light adaptation (8% vs. 1.2% of the presynaptic processes were invaginated by spinules). We suggest that the increased frequency of spinules during dark adaptation is related to an enhancement of synaptic transmission from a minor amacrine cell input when the major input from GABAergic amacrine cells is reduced. Also, the irregular surface of dark‐adapted Mb terminals may be related to the reduction of synaptic input during dark adaptation.
Cingulate input to the primary and supplementary motor cortices in the rhesus monkey: Evidence for somatotopy in areas 24c and 23c
Authors: Morecraft Robert J. , van Hoesen Gary W. 
Published: May 2005

AbstractWe examined the distribution of cingulate projections to the somatotopically related parts of the primary (M1) and supplementary (M2) motor cortices of the monkey by using fluorescent dyes. Labeled neurons were found in layers 3, 5 and 6 of areas 24c and 23c and were heaviest following injections placed in M2.Projections to analogous somatotopic areas in M1 and M2 arose from similar cingulate regions. In area 24c, neurons projecting to the face area of M1 and M2 were located anteriorly, those to the hindlimb were located posteriorly, and neurons projecting to the forelimb area of M1 and M2 were located in between. In area 23c, neurons projecting to the forelimb area of M1 and M2 were located anteriorly and those to the hindlimb area of M1 and M2 were located posteriorly. The face area of M1 and M2 was not found to receive afferents from area 23c. In contrast to this discreteness, cingulate projections to Woolsey's axial representation of M1 were diffuse.The results support the presence of a separate and somatotopically organized cingulate motor cortex in area 24c. This is predicated on the facts that: (1) small injections of retrograde tracers placed in analogous somatotopic parts of M1 and M2 resulted in similar patterns of labeling within the electrophysiologically “excitable” portion of the anterior cingulate cortex, and (2) this organized topography infers somatotopy. Our data fail to support a somatotopically organized cingulate motor area in area 23c if the criterion of all body parts is demanded. By virtue of its anatomical location and its connectional relation to the spinal cord and isocortical motor fields on the one hand and to the limbic cortex on the other, area 24c may be considered as M3 and provide limbic influences at several levels of motor control. © 1992 Wiley‐Liss, Inc.
Serotoninergic medullary raphespinal projection to the lumbar spinal cord in the rat: A retrograde immunohistochemical study
Authors: Jones S. L. , Light A. R. 
Published: May 2005

AbstractClassically the raphespinal system has been regarded as a Serotoninergic system; inhibition of spinal nociceptive transmission produced by stimulation of the medullary raphe nuclei is mediated partially by spinal Serotoninergic receptors. However, recent evidence suggests that the raphe nuclei are not homogeneous populations of Serotoninergic cells. The objective of the present study was to re‐examine, in the rat, the Serotoninergic raphespinal projection to the lumbar spinal cord, and to determine the relative contribution of Serotoninergic raphespinal neurons to the total population of raphespinal neurons.Microinjections of wheat‐germ agglutinin horseradish peroxidase conjugate coupled to colloidal gold into the lumbar spinal cord resulted in the retrograde labeling of 53% and 59% of the serotoninergic neurons in the raphe nuclei and in the para‐raphe zone, respectively Conversely, 47% and 28% of the retrogradely labeled neurons in the raphe and para‐raphe zone, respectively, demonstrated serotonin‐like immunoreactivity. Thus, contrary to previous reports, the present results suggest (1) that only about half of the serotoninergic neurons in the raphe nuclei and in the surrounding para‐raphe zone project to the lumbar spinal cord, and (2) that a large proportion of the neurons in the raphe nuclei (53%) and in the surrounding para‐raphe zone (72%) that project to the lumbar spinal cord are not serotoninergic. © 1992 Wiley‐Liss, Inc.
Survival and integration of bovine chromaffin cells transplanted into rat central nervous system without exogenous trophic factors
Authors: Ortega John D. , Sagen Jacqueline , Pappas George D. 
Published: May 2005

AbstractOur previous studies have demonstrated that suspension grafts of isolated bovine chromaffin cells survive in the periaqueductal gray (PAG) of rat midbrain for up to 1 year after transplantation. The current study aimed to determine whether this type of graft could survive transplantation into sites other than the PAG that can benefit from chromaffin cell secretory products.In this study, electron microscope analysis showed that chromaffin cells implanted into the frontal neocortex, striatum, PAG, or the subarachnoid space overlying the spinal cord survived for at least 8 weeks without evidence of degeneration. Intraparenchymally placed grafts appeared relatively avascular and well integrated within the host parenchyma. When blood vessels were found, they were primarily at the host‐graft border and were of the nonfenestrated central nervous system (CNS) type. Numerous synapses were present between the grafted cells and host neuronal processes. In addition, extensive intercommunication, via gap junction‐like structures, was common in the grafts. Morphologic evidence of granular secretion was most commonly seen in striatal grafts. In contrast, subarachnoid grafts displayed minimal interaction with the host spinal tissue and were heavily vascularized with fenestrated capillaries.Despite morphologic differences between intra‐ and extraparenchymal grafts, this study demonstrates that isolated suspensions of bovine chromaffin cells survive transplantation into CNS sites without exogenous trophic factors and suggests that these cells are potential candidates for neural transplantation into these regions. © 1992 Wiley‐Liss, Inc.
Nerve growth factor receptor‐immunoreactive neurons within the developing human cortex
Authors: Kordower Jeffrey H. , Mufson Elliott J. 
Published: May 2005

AbstractA monoclonal antibody recognizing the p75 receptor for nerve growth factor (NGF) was used to assess the immunohistochemical expression of NGF receptors within the developing human neo‐, limbic, and paralimbic cortices as well as the hippocampal complex. Between embryonic weeks 16 and 26, a transient population, of neurons located within the upper and lower subplate zones of the neo‐, limbic, and paralimbic cortices expressed the receptor for NGF. In contrast, NGF receptor‐immunoreactive neurons were only observed in the upper subplate zone of the entorhinal cortex at embryonic week 40 (term), a staining pattern not observed in a 5‐year‐old specimen. The expression of NGF receptor‐immunoreactive neurons within the upper subplate zone between embryonic weeks 16 and 40 was characterized by a dense band of immunoreactive neurons and neuropil. These neurons were bipolar with basal and apically directed neurites. NGF receptor‐immunoreactive neurons were also scattered throughout the lower subplate zone and underlying white matter between embryonic weeks 19 and 26. These neurons were multipolar, with less apically directed neurites. NGF receptor‐immunoreactive subplate neurons displayed a topographic distribution with the heaviest concentration found within limbic and paralimbic cortices as well as association neocortex. In contrast, light to moderate NGF receptor‐immunoreactivity was seen in sensory‐motor cortex. Within the hippocampal complex, only a few lightly stained NGF receptor‐immunoreactive neurons were seen within the fimbria, hilar region of the dentate gyrus, and subiculum. The expression of NGF receptor‐immunoreactivity increased within the subplate zone of the pre‐ and parasubiculum culminating in intense entorhinal cortex staining. As the entorhinal cortex merged with the developing inferior temporal association cortex, there was a marked reduction in staining intensity. In contrast to those in the subplate zone, neurons within the germinal zone and cortical plate were NGF receptor immunonegative at all times examined. The presence of NGF receptors in the subplate zone suggests that neurotrophins such as NGF play an important role in the transient viability of these neurons as well as in the guidance of cortical afferent inputs into topographically organized regions of the cerebral cortex. © 1992 Wiley‐Liss, Inc.
Rapid rearrangement of intrinsic tangential connections in the striate cortex of normal and dark‐reared kittens: Lack of exuberance beyond the second postnatal week
Authors: Lübke J. , Albus K. 
Published: May 2005

AbstractClustered intrinsic connections in the kitten striate cortex originate from an unclustered, diffusely organized pattern prevailing during the first postnatal week. We have studied the progress of this reorganization and its dependence on visual input by determining the topographies of the intrinsic tangential connections at various postnatal ages by means of axonal tracing methods. Neurons were labeled either by diffusion of the carbocyanin dye DiI in animals ranging in age between 1 day and 30 days, or by retrograde transport of fluorescent microspheres in animals ranging in age between 7 days and 11 months. Quantitative evaluation of retrogradely labeled neurons revealed that during the first postnatal week, intrinsic tangential connections are organized in an unclustered fashion. During the second postnatal week a rapid rearrangement of connections occurs and is complete around postnatal day 11. The main events taking place during the course of this rearrangement are a decrease in the density of tangential connections and an arrangement of them in a clustered fashion. Once the clusters have been formed, the periodicity of the clustered pattern of connections and the size and distinctness of the clusters do not change. This means that the system of clustered tangential connections is adult‐like at the end of the second postnatal week. Dark rearing affects neither the rapid rearrangement of horizontal connections into an adult‐like system of clusters, nor the integrity of this clustered topography until the end of the first postnatal month. The overall distribution and the lateral extent of the tangential connections remain about the same during the postnatal period and are not affected by dark rearing until the end of the first postnatal month. We conclude that the clustered system of tangential connections in the cat's striate cortex is determined innately. © 1992 Wiley‐Liss, Inc.