bluuebunny/crossref_metadata_2025_split huggingface dataset:
The early development of thalamocortical and corticothalarnic projections
Authors: Miller Brad , Chou Larry , Finlay Barbara L. 
Published: January 2005

AbstractThe early development ofthalamocortical and corticothalarnic projections in hamsters was studied to compare the specificity and maturation of these pathways, and to identify potential sources of information for specification of cortical areas. The cells that constitute these projections are both generated prenatally in hamsters and they make reciprocal connections. Fluorescent dyes (Dil and DiA) were injected into the visual cortex or lateral geniculate nucleus in fixed brains of fetal and postnatal pups. Several issues in axonal development were examined, including timing of axon outgrowth and target invasion, projection specificity, the spatial relationship between the two pathways, and the connections of subplate cells. Thalarnic projections arrive in the visual cortex 2 days before birth and begin to invade the developing cortical plate by the next day. Few processes invade inappropriate cortical regions. By postnatal day 7 their laminar position is similar to mature animals. By contrast, visual cortical axons from subplate and layer 6 cells reach posterior thalamus at l day after birth in small numbers. By 3 days after birth many layer 5 cell projections reach the posterior thalamus. On postnatal day 7, there is a sudden increase in the number of layer 6 projections to the thalamus. Surprisingly, these layer 6 cells are precisely topographically mapped with colabeied thalarnic afferents on their first appearance. Subplate cells constitute'a very small component of the corticothalarnic projection at all ages. Double injections of Dil and DiA show that the corticofugal and thalamocortical pathways are physically separate during development. Corticofugal axons travel deep in the intermediate zone to the thalarnic axons and are separate through much of the internal capsule. Their tangential distribution is also distinct. The early appearance of the thalamocortical pathway is consistent with an organizational role in the specification of some features of cortical cytoarchitecture. The specific initial projection of thalamocortical axons strongly suggests the recognition of particular cortical regions. The physical Separation of these two pathways limits the possibility for exchange of information between these Systems except at their respeetive targets. © 1993 Wiley‐Liss, Inc.
Subcortical connections of inferior temporal areas TE and TEO in macaque monkeys
Authors: Webster Maree J. , Bachevalier Jocelyne , Ungerleider Leslie G. 
Published: January 2005

AbstractTo investigate the subcortical connections of inferior temporal cortex, we injected its anterior and posterior portions (Bonin and Bailey's cytoarchitectonic areas TE and TEO, respectively) in 6 rhesus monkeys with retrograde and anterograde tracers. The results indicate that both areas TE and TEO receive nonreciprocal inputs from several thalarnic nuclei, including paracentralis, ventralis anterior, centralis, and limitans, and that TE also receives input from reuniens. Additional nonreciprocal inputs to both areas arise from the hypothalamus, basal nucleus of Meynert, dorsal and median raphe, loeus coeruleus, and reticular formation. TE and TEO are reciprocally connected with the lateral, medial, and inferior nuclei of the pulvinar and with the ventral portion of the claustrum. The main subcortical nonreciprocal Output from TE and TEO is to the striatum and from TEO to the superior colliculus. TE also sends a vcry limited projection to nucleus medialis dorsalis magnocellularis of the thalamus. AK‐huugh the connections of areas TE and TEO are overlapping in most subcortical structures, they are partially segregated in the pulvinar, the reticular nucleus of the thalamus, and the striatum. Specifically, relative to those of TE, the projections of TEO are located more laterally in the medial, lateral, and inferior nuclei of the pulvinar, more ventrally in the reticular nucleus, and more caudally in both the ventral putamen and tail and head of the caudate nucleus. e 1993 Wile.v‐Liss. Inc.This article is a US Government work and, as such, is in the public domain in the United State of America.
Topographical representation of shoulder motor nuclei in the cat spinal cord as revealed by retrograde fluorochrome tracers
Authors: Hörner Michael , Kümmel Heinrich 
Published: January 2005

AbstractThe present investigation demonstrates the morphological relationships among the main shoulder motor nuclei within the spinal cord of the cat. The intraspinal position of these nuclei has been revealed by retrograde labelling of spinal motor neurones via their peripheral nerves supplying anatomically identified shoulder muscles. Multiple pressure injection of up to four fluorescent tracers (Bisbenzimide, Fast Blue, Fluoro‐Gold, Rhodamine‐b‐isothiocyanate) in one experiment was used to show the longitudinal distribution and topographical relations of motor neurones projecting to muscles acting on the scapulo‐humerus joint. Tracer‐positive cells have been found from middle C5 to rostral Th2 in the cervical cord, forming coherent longitudinal cell clusters separated in medial and lateral projection fields in the ventral horn. The present data suggest that the anatomical organization of spinal shoulder motor neurones corresponds to the embryonic origin of their later target muscles. All medial motor nuclei project to muscles deriving from ventral embryonic origins, while those motor nuclei lying in lateral positions innervate muscles originating from dorsal muscle primordia. Therefore, the spinal topography of shoulder motor nuclei seems to be independent of both the position and the funciton of a given muscle in the adult animal. © 1993 Wiley‐Liss, Inc.
Relationship of descending inferior colliculus projections to olivocochlear neurons
Authors: Thompson Ann M. , Thompson Glenn C. 
Published: January 2005

AbstractWith the objective of defining the relationship of descending inferior colliculus projections to the olivocochlear system in the guinea pig, inferior colliculus neurons were anterogradely labeled with Phaseolus vulgaris‐leucoagglutinin and olivocochlear neurons were retrogradely labeled with horseradish peroxidase in the same brain sections. Inferior colliculus neurons were found to project to many nuclei and regions of the hindbrain where olivocochlear neurons reside. The most substantial of these descending projections was to the ipsilateral medioventral periolivary region. Fewer descending projections terminated in the ipsilateral ventral nucleus of the lateral lemniscus, superior paraolivary nucleus, and rostral periolivary region; and even fewer ipsilateral projections terminated in the area surrounding the lateral superior olive, caudal periolivary region, and the lateroventral periolivary region. Descending neurons of the inferior colliculus also project to the contralateral hindbrain first via the lateral lemniscus and then the trapezoid body, to terminate in the contralateral medioventral periolivary region, superior paraolivary nucleus, rostral periolivary region, and the ventral nucleus of the lateral lemniscus. In addition to the projections into these regions that contain olivocochlear neurons, there are varicosities of inferior colliculus neurons that appear to contact the olivocochlear neurons themselves, both ipsilaterally and contralaterally, especially, but not only, in the ipsilateral medioventral periolivary region. We therefore conclude that descending inferior colliculus neurons do provide input to olivocochlear neurons and that the input is not limited to olivocochlear neurons of the ipsilateral medioventral periolivary region. However, given the robust nature of the projection to the ipsilateral medioventral periolivary region and the paucity of contacts observed in that region, we also conclude that the olivocochlear neuron is not the major target of descending inferior colliculus projections. © 1993 Wiley‐Liss, Inc.
Cellular and subcellular distribution of HNK‐1 immunoreactivity in the neural tube of Xenopus
Authors: Nordlander Ruth H. 
Published: January 2005

AbstractThe HNK‐1 antigen, a carbohydrate moiety bound to many cell adhesion and recognition molecules, is implicated in cell‐cell and cell‐substrate interactions during neural development. HNK‐1 immunoreactivity (HNK1‐IR) appears on neurons of the Xenopus neural tube very early in their development (Nordlander, Devel. Brain Res., 50:147‐153, 1989). The distribution and onset of expression of the HNK‐1 epitope on and within individual neurons is examined in this study. HNK‐1 labels developing neurons and their processes, and focal areas of other structures which are directly contacted by neurons, such as neuroepithelial cell surfaces, basal lamina, and culture surfaces. HNK1‐IR first appears in the Golgi apparatus and subsequently on the cell surface and in streams of punctate material directed toward the site of axon initiation and into the developing axon and its growth cone. The entire neuron is coated with a thin (20‐30 nm) surface layer of HNK1‐IR. In addition, the surface is dotted with small (100‐250 nm) boluses of HNK1‐IR material. Such boluses also occur within cytoplasmic vesicles, and extracellularly on basal lamina and culture substrata in proximity to neurons or their processes. The subcellar distribution of HNK1‐IR in this tissue is compatible with a role for the HNK‐1 epitope in axonal outgrowth and guidance. © 1993 Wiley‐Liss, Inc.
Merkel‐like basal cells in Necturus taste buds contain serotonin
Authors: Delay R. J. , Taylor R. , Roper S. D. 
Published: January 2005

AbstractSeveral types of cells have been identified in vertebrate taste buds, including dark cells, light cells, intermediate cells, type III cells, and basal cells. The physiological roles of these cell types are not well understood, especially those of basal cells. In this paper we show that there are two types of basal cells in taste buds from Necturus maculosus. One type of basal cell is an undifferentiated cell, presumably a stem cell. By combining light microscopic immunocytochemistry with electron microscopy, we show that the other type of basal cell is positive for serotonin‐like immunoreactivity and that these cells have ultrastructural features similar to those found in cutaneous Merkel cells. Based on these findings, and the fact that the Merkel‐like taste cells have been shown to make synaptic contacts with adjacent taste cells and with innervating nerve fibers, we conclude that these Merkel‐like basal taste cells are serotonergic interneurons. © 1993 Wiley‐Liss, Inc.
Immunocytochemical localization of the amino acid neurotransmitters in the chicken retina
Authors: Kalloniatis Michael , Fletcher Erica L. 
Published: January 2005

AbstractPostembedding immunocytochemistry was used to determine the cellular localization of the amino acid neurotransmitters glutamate, aspartate, gamma‐aminobutyric acid (GABA), and glycine in the avian retina. The through retinal pathway was glutamatergic, with all photoreceptors, bipolar cells, and ganglion cells being immunoreactive for glutamate. Bipolar cells displayed the highest level of glutamate immunoreactivity, with the cell bodies terminating just below the middle of the inner nuclear layer. All lateral elements, horizontal cells, amacrine cells, and interplexiform cells were immunoreactive for glycine or GABA. The GABAergic neurons consisted of two classes of horizontal cells and amacrine cells located in the lower part of the inner nuclear layer. GABA was also localized in displaced amacrine cells in the ganglion cell layer, and a population of ganglion cells that co‐localize glutamate and GABA. Both the horizontal cells and GABAergic amacrine cells had high levels of glutamate immunoreactivity, which probably reflects a metabolic pool. At least two types of horizontal cells in the avian retina could be discriminated on the basis of the presence of aspartate immunoreactivity in the H2 horizontal cells. Glycine was contained in a subclass of amacrine cells, with their cell bodies located between the bipolar cells and GABAergic amacrine cells, two subclasses of bipolar cells, displaced amacrine cells in the ganglion cell layer, and ganglion cells that colocalize glutamate and glycine. Glycinergic amacrine cells had low levels of glutamate. We have also identified a new class of glycinergic interplexiform cell, with its stellate cell body located in the middle of the inner nuclear layer among the cell bodies of bipolar cells. Neurochemical signatures obtained by analyzing data from serial sections allowed the classification of subclasses of horizontal cells, bipolar cells, amacrine cells, and ganglion cells. © 1993 Wiley‐Liss, Inc.
Prefrontal connections of medial motor areas in the rhesus monkey
Authors: Bates Julianna F. , Goldman‐Rakic Patricia S. 
Published: January 2005

AbstractSeveral areas on the medial surface of the frontal lobe in both monkeys and humans, including the supplementary motor area and specific areas within the ventral bank of the cingulate sulcus called the cingulate motor areas, have been implicated in the initiation and execution of skiled movements. These areas project directly to the motor cortex and spinal cord, and, on this basis alone, can be considered premotor areas. The present study investigated whether these premotor areas are specific targets of prefrontal cortical projections in the rhesus monkey and thereby provide links between this association cortex and motor effector pathways. Circumscribed injections of wheat germ agglutinin‐conjugated horseradish peroxidase were placed into different cytoarchitectonic subdivisions of prefrontal cortex, and resultant retrograde and anterograde labeling examined with respect to designated premotor targets. Conversely, injections were also made in the supplementary and cingulate motor areas and labeled cells and terminals charted in the prefrontal cortex.A principal finding in this study is the identification of multiple prefrontal regions that project to the supplementary motor area, the cingulate motor areas, or both. Areas 46, 8a, 9, 11, and 12 are reciprocally connected with an area of the superior frontal gyrus in or near the supplementary motor area at its rostral margin. A smaller constellation of prefrontal areas, areas 46, 8a, and 11, is reciprocally connected with portions of cingulate cortex that have been classified as premotor arm and/or leg representations (Hutchins et al., Exp Brain Res 71:667–672, 1988). In accordance with numerous previous reports, prefrontal areas 46, 8a, 9, 10, 11, and 12 are reciprocally connected with “nonmotor” subdivisions of cingulate cortex.The results presented here specify the corticocortical connections by which prefrontal cortex may influence motor output. © 1993 Wiley‐Liss, Inc.
Roles of estradiol and progesterone in regulation of hippocampal dendritic spine density during the estrous cycle in the rat
Authors: Woolley Catherine S. , McEwen Bruce S. 
Published: January 2005

AbstractWe have previously shown that the density of dendritic spines on hippocampal CA1 pyramidal cells is dependent on circulating estradiol and progesterone and fluctuates naturally during the 5 day estrous cycle in the adult rat. To date, however, no detailed characterization of the roles that these hormones play in regulation of spine density has been made. In order to determine the time courses and extent of the effects of estradiol and progesterone on dendritic spine density, we have analyzed the density of dendritic spines on the lateral branches of the apical dendritic tree of Golgi‐impregnated CA1 hippocampal pyramidal cells in several experiments. In summary, our findings included the following: (1) Following ovariectomy, circulating estradiol is undetectable within 24 hours; however, spine density decreases gradually over a 6 day period. (2) Spine density does not decrease any further up to 40 days following ovariectomy. (3) Treatment with estradiol alone can reverse the ovariectomy‐induced decrease in spine density. (4) Spine density begins to increase within 24 hours following estradiol benzoate injection in an ovariectomized animal, peaks at 2 and 3 days, then gradually decreases over the next 7 day period. (5) Although free estradiol is metabolized more rapidly than estradiol benzoate, there is no difference in the rate of decrease in spine density following injection of either form. (6) Progesterone has a biphasic effect on spine density in that progesterone treatment following estradiol initially increases spine density for a period of 2 to 6 hours but then results in a much sharper decrease than is observed following estradiol alone. By 18 hours following progesterone treatment, spine density is decreased nearly to 6 day ovariectomy values. (7) Treatment of intact rats with the progesterone receptor antagonist, RU 486, during the proestrus phase of the estrous cycle inhibits the proestrus to estrus drop in spine density. These findings account for both the gradual increase and rapid decrease in spine density which we have previously observed during the estrous cycle and indicate that progesterone in particular may be an important factor in the regulation of rapid morphologic changes which occur naturally in the adult brain. © 1993 Wiley‐Liss, Inc.
Postnatal development of the cholecystokinin innervation of monkey prefrontal cortex
Authors: Oeth Kristen M. , Lewis David A. 
Published: January 2005

AbstractAlthough the structure and function of primate prefrontal cortex undergo substantial modifications during postnatal development, relatively little is known about the maturation of neurotransmitter systems in these cortical regions. In the primate brain, cholecystokinin is present in the greatest concentrations in prefrontal regions. Thus, in this study, we used immunohistochemical techniques to investigate the postnatal development of the cholecystokinin innervation of monkey prefrontal cortex.In animals aged 4 days through adult, cholecystokinin immunoreactivity was present in nonpyramidal neurons that appeared to represent at least two distinct cell types. The most common type was a vertically oval bitufted neuron, located in layers II‐superficial III, which typically had a radially descending axon that gave rise to short collaterals in layer IV. Another frequently observed cell type was a larger multipolar neuron located in the superficial half of layer III. The axon of these neurons branched locally in the vicinity of the cell body.The greatest density of cholecystokinin‐containing neurons and processes was present in monkeys less than 1 month of age. The density of immunoreactive structures in every prefrontal region then progressively declined with increasing age, with the most marked changes occurring during the first postnatal year. As a result, the density of labeled neurons in adult monkeys was less than one‐third of that in neonatal monkeys. However, labeled structures were significantly more dense in some ventromedial and orbital regions than in dorsal regions of the prefrontal cortex in neonatal, but not in older animals.In all animals, cholecystokinin‐containing neurons were present in highest density in layers II‐superficial III, and labeled terminal fields were observed in layers II, IV, and VI. In animals less than 1 month of age, fascicles of radial fibers traversed through layers III and V, whereas in animals 1 to 3 months of age, individual radial fibers rather than fiber bundles were present in layers III and V. In addition, immunoreactive pericellular arrays, which appeared to surround unlabeled nonpyramidal cells, were present in layers V and VI and the subcortical white matter in the youngest monkeys.Although many aspects of the cholecystokinin innervation of monkey prefrontal cortex remain constant during postnatal life, the distinct developmental changes in the cholecystokinin innervation of these regions suggest that it may play an important role in the maturation of the cortical circuitry that mediates the acquisition of certain cognitive abilities. © 1993 Wiley‐Liss, Inc.
Neurons synthesizing nitric oxide innervate the mammalian carotid body
Authors: Wang Z.‐Z. , Bredt D. S. , Fidone S. J. , Stensaas L. J. 
Published: January 2005

AbstractThe carotid body is an arterial chemoreceptor organ sensitive to blood levels of O2, CO2 and pH. The present immunocytochemical and neurochemical study has demonstrated the presence of an extensive plexus of nitric oxide (NO)‐synthesizing nerve fibers in this organ. These nitric oxide synthase (NOS)‐containing axons are closely associated with parenchymal type I cells and with blood vessels in the carotid body. Denervation and retrograde tracing experiments have revealed that these fibers arise from NOS‐immunoreactive and nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase‐positive neuronal cell bodies located in the petrosal ganglion and the carotid body, and dispersed along the glossopharyngeal and carotid sinus nerves (CSN). Within the petrosal ganglion, these neurons are topographically segregated from the catecholaminergic cells, and they contain the neuropeptide, substance P. NOS‐positive autonomic microganglial cells in the carotid body and CSN also exhibit choline acetyltransferse (ChAT) immunoreactivity. Our results suggest that nitric oxide may be a novel neuronal messenger in the mammalian carotid body involved in the modulation of chemosensory transduction and transmission in this organ. © 1993 Wiley‐Liss, Inc.
NCAM expression by subsets of taste cells is dependent upon innervation
Authors: Smith David V. , Akeson Richard A. , Shipley Michael T. 
Published: January 2005

AbstractThe expression of the neural cell adhesion molecule (NCAM) and distinct carbohydrate groups by cells of the taste buds of the rat vallate papilla was investigated by immunohistochemical and biochemical techniques. We employed antibodies against (1) the extracellular (mAb 3F4) and cytoplasmic (mAb 5B8) portions of the NCAM polypeptide, (2) the highly sialylated form of NCAM (mAb 5A5), (3) carbohydrate epitopes associated with glycosylated NCAM forms in the rat (mAb 2B8) or frog (mAb 9‐OE) olfactory system, and also (4) the Lewisb blood group carbohydrate epitope (mAb CO431). NCAM mRNA was demonstrated by polymerase chain reaction (PCR) in samples of the vallate papilla, suggesting the presence of NCAM in cells of the taste buds. Antibodies against NCAM (mAbs 3F4 and 5B8) recognized a subset (about 20%) of cells within the vallate taste buds; fibers of the glossopharyngeal nerve, including those innervating the gustatory epithelium, were NCAM immunoreactive. Taste bud cells did not express polysialic acid (mAb 5A5), but mAb 5A5 immunoreactivity was observed on fibers of the IXth nerve, including a few that entered the taste buds. All or nearly all of the cells within the vallate taste buds were immunoreactive to mAb 2B8, whereas mAbs 9‐OE and CO431 reacted with subsets of cells. The carbohydrates recognized by mAbs 2B8 and 9‐OE were also abundantly expressed in the ducts and acini of the lingual salivary glands. Bilateral crush of the IXth nerve resulted in the loss of expression of all of these molecules from the gustatory epithelium. If cells of the taste bud express NCAM during their final stage(s) of differentiation, then NCAM could play a role(s) in the growth of gustatory axons toward their target epithelial cells and in the recognition between the nerve fibers and mature taste receptor cells, or among the taste bud cells themselves. © 1993 Wiley‐Liss, Inc.