bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of transitory corpus callosum axons projecting to developing cat visual cortex revealed by DiI
Authors: Elberger Andrea J. 
Published: January 2005

AbstractFunctional studies of the development of the corpus callosum in the cat have shown that an intact callosum during postnatal month 1 is necessary for normal visual development. In vivo tracing techniques have not provided enough information on corpus callosum connectivity to fully evaluate the evidence for a morphological mechanism for the functional effects of neonatal callosum section. However, lipophilic in vitro membrane tracers permit a more detailed search for such evidence because the entire limit of many cells can be labeled simulatanously. To investigate the morphological basis for the observed functional results in cats, the corpus callosum was labeled in vitro with the carbocyanine dye, DiI. Crystals of DiI were placed in the midsagittal callosum in tissue from 2 to 277‐day‐old cats. Tissue was coronally sectioned 3–22 months later. Sections were photographed and reconstructed to show the overall distribution of corpus callosum projections, as well as the locations of individual corpus callosum axons and their presumed terminals.The distribution of corpus callosum projections, examined in cortical areas 17–19, 7, and posterior medial lateral suprasylvian cortex, changes significantly during development. During postnatal week 1, callosal axons extend throughout these cortical areas to layer I. Numerous varicosities on callosal axons are located en passant and at axon terminals in layer I. During postnatal week 2, the density of callosal projections is reduced in all cortical areas, although many axons still extend to layer I. By postnatal month 2, the callosal axons extending to layer I are predominantly near the border with adjacent cortical areas; in the nonborder regions of these areas, many axons extend to layer VI while a much smaller number of axons extend to layers II–V. By postnatal month 3, the callosal projections to supragranular layers are almost exclusively restricted to cytoarchitectonic border regions; in the remaining regions, including medial area 17, there are occasional axons extending to the supragranular layers and only a moderate number of axons extending to infragranular layers.Thus, a substantial number of elaborately formed transitory corpus callosum axons, distributed throughout visual cortex, exist for several weeks during postnatal development; in area 17, these axons are found in central through peripheral visual field representations. The transitory callosal axons appear to have axon terminals in layer I as well as en passant terminals while extending through layers II–VI. If some of these terminals were to form synapses, there would be extensive opportunities for the corpus callosum to provide input to layers I–VI throughout visual cortex during the period of development in which cortical microcircuitry is being established. © 1993 Wiley‐Liss, Inc.
Quantitative autoradiographic localization of [125I]insulin‐like growth factor I, [125I]insulin‐like growth factor II, and [125I]insulin receptor binding sites in developing and adult rat brain
Authors: Kar S. , Chabot J.‐G. , Quirion R. 
Published: January 2005

AbstractInsulin‐like growth factors I and II (IGF I and IGF II) and insulin itself, which are structurally related polypeptides, play an important role in regulating brain growth and development as well as in the maintenance of its normal functions during adulthood. In order to provide a substrate for the better understanding of the roles of these growth factors, we have investigated the anatomical distribution as well as the variation in the density of [125I]IGF I, [125I]IGF II, and [125I]insulin receptor binding sites in developing and adult rat brain by in vitro quantitative autoradiography. The distributional profile of [125I]IGF I, [125I]IGF II, and [125I]insulin receptor binding sites showed a widespread but selective regional localization throughout the brain at all stages of development. The neuroanatomic regions which exhibited relatively high density of binding sites with each of these radioligands include the olfactory bulb, cortex, hippocampus, choroid plexus, and cerebellum. However, in any given region, receptor binding sites for IGF I, IGF II, or insulin are concentrated in anatomically distinct areas. In the cerebellum, for example, [125I]IGF II receptor binding sites are concentrated in the granular cell layer, [125I]insulin binding sites are localized primarily in the molecular layer, whereas [125I]IGF I receptor binding sites are noted in relatively high amounts in granular as well as molecular cell layers. The apparent density of sites recognized by each radioligand also undergoes remarkable variation in most brain nuclei, being relatively high either during late embryonic (i.e., IGF I and IGF II) or early postnatal (i.e., insulin) stages and then declining gradually to adult levels around the third week of postnatal development. These results, taken together, suggest that each receptor‐ligand system is regulated differently during development and thus may have different roles in the process of cellular growth, differentiation, and maintenance of the nervous system. Furthermore, the localization of [125I]IGF I, [125I]IGF II, and [125I]insulin receptor binding sites over a wide variety of physiologically distinct brain regions suggests possible involvement of these growth factors in a variety of functions associated with specific neuronal pathways. © 1993 Wiley‐Liss, Inc.
Distribution of GAP‐43 mRNA in the adult rat brain
Authors: Kruger Lawrence , Bendotti Caterina , Rivolta Romano , Samanin Rosario 
Published: January 2005

AbstractRegional distribution of gene expression of the axonal growth‐associated protein, GAP‐43, was studied in adult rat brains by in situ hybridization autoradiography to determine the features of mature neuronal populations that synthesize GAP‐43 protein. Such synthesis appears to correlate with axonal growth during maturation and regrowth after axotomy. In most adult neurons, the sharp decline in GAP‐43 gene expression implies a reduced capacity for axonal growth. Neurons capable of extending axonal knobs in the absence of injury may indicate a “plasticity” underlying dynamic processes of interaction between neurons and their synaptic targets.Antisense and sense (control) riboprobes were used on serial sections in the three principal axes, and the magnitude of hybridization signal was examined to determine regional patterns. GAP‐43 mRNA levels are pronounced in diverse neuronal groups including the locus coeruleus, raphé nn., dopaminergic nigral and ventral tegmental nn., mitral cells, hippocampal CA3, inferior olivary n., vagal motor n. and other parasympathetic preganglionic neurons, select thalamic midline and intralaminar nn., several specific nn. of the hypothalamus and basal forebrain, the granular layer of cerebellar cortex, the infragranular neocortex, and the granular olfactory paleocortex; there is substantial range in the magnitude of expression. Regions revealing minimal signal include most thalamic sensory relay nuclei, the granule neurons of the olfactory bulb and dentate gyrus, and the caudate and putamen.Possible concomitants of GAP‐43 expression include regulation of ion flux and neurotrans‐mitter release. Those neurons with long, extensively dispersed and numerous synaptic connections display the strongest signals and may possess the greatest propensity forcontinuous growthand turnover of their axon terminals, in contrast to short‐axon and specific projection neurons exhibiting minimal levels. These data may enable inferring which populations display normal or experimentally induced axonal growth. © 1993 Wiley‐Liss, Inc.
Imparied motor axon regeneration in the C57BL/Ola mouse
Authors: Chen S. , Bisby M. A. 
Published: January 2005

AbstractThe delayed Wallerian degeneration which occurs in the C57BL/Ola mouse is associated with impaired motor axon regeneration. Following sciatic nerve crush, recovery of the sciatic functional index was delayed and incomplete when compared with recovery in C57BL/6J mice. After facial nerve crush, recovery of whisker movement in Ola mice was also delayed, and there was a prolonged period of partial recovery, not seen in 6J mice. Regeneration rate of the motor axons was measured by the axonal transport technique in sciatic nerve and was approximately 0.7 mm/d for Ola mice, and 4.0 mm/d for 6J mice. Combining these results from our previous work, we conclude that regeneration of both sensory and motor axons is imparired when Wallerian degeneration does not follow its usual time course after injury. © 1993 Wiley‐Liss, Inc.
Immunohistochemical study of the pattern of rapid expression of c‐fos protein in the visual cortex of dark‐reared kittens following initial exposure to light
Authors: Beaver C. J. , Mitchell D. E. , Robertson H. A. 
Published: January 2005

AbstractBrief alterations to the nature of the visual input during critical periods in the early life of cats and monkeys can result in rapid anatomical and physiological changes in the central visual pathways. The immediate early genes (IEGs) represent a possible way in which these changes could be mediated since the protein products of a number of these genes have been shown to be induced rapidly in neurons in response to a variety of transynaptic stimuli.Immunohistochemical methods were employed to examine the tempo and pattern of expression of Fos, the protein product of the c‐fos gene, induced in the visual cortex of kittens dark‐reared from birth to 30 days of age by brief periods of binocular visual exposure. In visual cortical area 17, the number of Fos immunoreactive cells increased rapidly from virtually zero in control kittens that received no visual exposure, to reach high levels in animals that received between 1 and 2 hours of visual experience. Immunoreactive cells were absent in the dorsal lateral geniculate nucleus, but were numerous in the ventral lateral geniculate nucleus, and in area 17, were most numerous in the extragranular layer (2, 3 and 6) but sparse in lower layer 4 and layer 5, and virtually absent in layer 1. Substantial constitutive Fos immunoreactivity was observed in area 17 of normal 30‐day‐old kittens but very few immunopositive cells were evident in adult animals. However, Fos immunoreactivity was observed in the visual cortex of a dark‐reared (for 30 days) adult animal following a brief period of visual exposure, a finding that suggests that Fos might serve other roles in the visual cortex in addition to those it might play uniquely during development. It is suggested that Fos, in combination with the protein products of a select number of other IEGs, may mediate a variety of rapid changes in the visual cortex including those that underlie visual system plasticity during early postnatal life. © 1993 Wiley‐Liss, Inc.
Distribution of acetylcholine receptors in the central nervous system of adult locusts
Authors: Leitch Beulah , Watkins Branwen L. , Burrows Malcolm 
Published: January 2005

AbstractA polyclonal antibody raised against nicotinic acetylcholine receptor protein from purified locust neuronal membrane was used to analyse the distribution of antigenic sites within the central nervous system of adult Schistocerca gregaria. Light microscopic examination showed that all principal neuropiles in the thoracic ganglia label with the antibody but that the major tracts and commissures do not. Analysis of this pattern of staining in the electron microscope reveals that the receptor is present on specific synaptic and extrajunctional neuronal membranes in the neuropile. Antigenic sites are also evident on the plasma membranes and within the cytoplasm adjacent to Golgi complexes of some neuronal somata, suggesting that these neurones synthesise nicotinic acetylcholine receptors. In addition to neuronal labelling, there is evidence that the receptor is also present on the membranes of three types of glial cells. The implications of this pattern of receptor distribution are discussed. © 1993 Wiley‐Liss, Inc.
Cloning and characteristics of fish glial fibrillary acidic protein: Implications for optic nerve regeneration
Authors: Cohen Ilana , Shani Yael , Schwartz Michal 
Published: January 2005

AbstractMammalian central nervous system neurons do not regenerate after axonal injury, unlike their counterparts in fish and amphibians. After axonal injury, glial cells in mammals do not support regrowth of axons, while in fish they support the regeneration process. Controversy exists as to whether or not the intact fish optic nerve expresses glial fibrillary acidic protein, a well‐known marker for mature astrocytes, and thus whether its astrocytes differ in this respect from those of the brain and spinal cord, as well as from optic nerve astrocytes of other species. In an attempt to resolve this question we cloned fish glial fibrillary acidic protein. Two different complementary DNA clones were isolated from a carp brain complementary DNA library, each encoding a different form of glial fibrillary acidic protein apparently originating from different genes. Monospecific polyclonal antibodies were raised against a peptide synthesized according to the predicted amino acid sequence, and used to identify and localize the fish glial fibrillary acidic protein. Two glial fibrillary acidic proteins (of 49 kDa and 51 kDa) were identified by the antibodies in all tested fish central nervous system tissues. The antibodies were then used to examine glial fibrillary acidic protein immunoreactivity in sections taken from uninjured and injured optic nerves of goldfish. Injury was followed by an elevation in glial fibrillary acidic protein immunoreactivity along the whole length of the nerve, except at the site of the injury, where—as in the case of vimentin—no immunoreactivity was detectable. However, in contrast to vimentin‐positive glial cells, which repopulate the site of the injury soon after the optic nerve is injured, glial fibrillary acidic protein‐positive glial cells remained outside the injury site for as long as 6 weeks after the injury. Despite the injury‐induced changes in glial fibrillary acidic protein immunoreactivity, no change was observed in the level of transcript encoding glial fibrillary acidic protein after injury, while there was an increase in the amount of glial fibrillary acidic protein associated with the cytoskeleton and a reduction in the soluble form. These results suggest that the injury‐induced changes in immunoreactivity on sections involve changes not in transcription or translation of glial fibrillary acidic protein, but in glial fibrillary acidic protein compartmentalization. © 1993 Wiley‐Liss, Inc.
Ultrastructure of synapses from the pretectum in the A‐laminae of the cat's lateral geniculate nucleus
Authors: Cucchiaro Josephine B. , Uhlrich Daniel J. , Sherman S. Murray 
Published: January 2005

AbstractWe have recently shown in cats that many neurons projecting to the lateral geniculate nucleus from the pretectum use γ‐amino butyric acid (GABA) as their neurotransmitter. We sought to determine the morphology of synaptic terminals and synapses formed by these pretectal axons and the extent to which they resemble other GABAergic terminals found in the geniculate neuropil (i.e., from geniculate interneurons and cells of the nearby perigeniculate nucleus). To do this, we labeled a population of pretectal axons with the anterograde tracer Phaseolus vulgaris leucoagglutinin and analyzed the morphology and synaptology of labeled pretectal terminals in the A laminae of the cat's lateral geniculate nucleus. The pretectal projection, which arises primarily from the nucleus of the optic tract (NOT), provides synaptic innervation to elements in the geniculate neuropil. The labeled NOT terminals are densely packed with vesicles, contain dark mitochondria, and form symmetrical synaptic contacts. These are characteristics of the F1 type of terminal, and we know from other studies that GABAergic axon terminals from interneurons and perigeniculate cells also give rise to F1 terminals. We compared our population of NOT terminals with labeled perigeniculate and unlabeled F1 terminals selected from the geniculate neuropil and found that all three populations share many morphological characteristics. Both qualitative and quantitative assessments of the pretectal terminals suggest that these are a type of F1 terminal. Most pretectal terminals selectively form synapses onto geniculate profiles that contain irregularly distributed vesicles and dark mitochondria and that are postsynaptic to other types of terminals. These postsynaptic targets thus exhibit features of another class of inhibitory, GABAergic terminal known as F2 terminals, which are the specialized appendages of geniculate interneurons. Pretectal inputs, being GABAergic, may thus serve to inhibit local interneuronal outputs. Pretectal axons also innervate the perigeniculate nucleus, in which the only targets are the other main type of inhibitory, GABAergic neurons. These results suggest that the pretectum may facilitate retinal transmission through the lateral geniculate nucleus by providing inhibition to the local inhibitory cells: the interneurons and probably perigeniculate cells. This would serve to release geniculate relay cells from inhibition. © 1993 Wiley‐Liss, Inc.
Ipsilateral cortical projections to areas 3a, 3b, and 4 in the macaque monkey
Authors: Darian‐Smith Corinna , Darian‐Smith Ian , Burman Kathleen , Ratcliffe Neil 
Published: January 2005

AbstractIn the macaque monkey area 3a of the cerebral cortex separates area 4, a primary motor cortical field, from somatosensory area 3b, which has a subcortical input mainly from cutaneous mechanoreceptive neurons. That each of these cortical areas has a unique thalamic input was illustrated in the preceding paper. In the present experiments the cortical afferent projections to these 3 areas of the sensorimotor cortex monkey were visualized and compared, using 4 differentiable fluorescent dyes as axonal retrogradely transported labels. The cortical projection patterns to areas 3a, 3b, and 4 were similar in that they each consisted of (a) a “halo” of input from the immediately surrounding cortex, and (b) discrete projections from one or more remote cortical areas. However, the pattern of remote inputs from precentral, mesial, and posterior parietal cortex was different for each of the 3 cortical target areas. The cortical input configuration was least complex for area 3b, its remote input projecting mainly from insular cortex. The pattern of discrete cortical inputs to the motor area 4, however, was more complex, with projections from the cingulate motor area (24c/d), the supplementary motor area, postarcuate cortex, insular cortex, and postcentral areas 2/5. Area 3a, in addition to the proximal projections from the immediately surrounding cortex, also received input from the supplementary motor area, cingulate motor cortex, insular cortex, and areas 2/5. Thus, this pattern of cortical input to area 3a resembled more closely that of the adjacent motor rather than that of the somatosensory area 3b. Contrasting with this, however, the thalamic input to area 3a was largely from somatosensory VPLc (abbreviations from Olszewski [1952] The Thalamus of the Macaca mulatta. Basel: Karger) and not from VPLo (with input from cerebellum, and projecting to precentral motor areas). © 1993 Wiley‐Liss, Inc.
Distribution of the mRNA for a metabotropic glutamate receptor (mGluR3) in the rat brain: An in situ hybridization study
Authors: Ohishi Hitoshi , Shigemoto Ryuichi , Nakanishi Shigetada , Mizuno Noboru 
Published: January 2005

AbstractDistribution of the mRNA for a metabotropic glutamate receptor, mGluR3, which is coupled to the inhibitory cAMP cascade, was examined in the central nervous system of the adult albino rat by in situ hybridization. The hybridization signals of mGluR3 were detected not only on neuronal cells but also on many glial cells throughout the brain and spinal cord. In the neuronal cells, prominent expression of mGluR3 mRNA was seen in the thalamic reticular nucleus. Moderately labeled neurons were seen in the anterior olfactory nucleus, cerebral neo and mesocortical regions, lateral amygdaloid nucleus, ventral part of the basolateral amygdaloid nucleus, dorsal endopiriform nucleus, supraoptic nucleus, superficial layers of the superior colliculus, inferior colliculus, interpeduncular nucleus, superior olivary nuclei, and Golgi cells in the cerebellar cortex. Weakly labeled neurons were observed in the striatum, nucleus accumbens, ventral pallidum, globus pallidus, entopeduncular nucleus, lateral hypothalamic area, hypothalamic paraventricular nucleus, medial habenular nucleus, anterior pretectal nucleus, Barrington's nucleus, Nucleus O, paragenual nucleus, trigeminal sensory complex, cochlear nuclei, dorsal motor nucleus of the trigeminal nerve, dorsal cap of the inferior olive, spinal dorsal horn, and lamina X of the spinal cord. The stellate cells in the cerebellar cortex, and neurons in the deep cerebellar nuclei were also labeled weakly. The granule cell layer of the dentate gyrus, as a whole, appeared to be labeled intensely, but each of the granule cells was labeled only weakly. No significant labeling was detected in the mitral and tufted cells in the olfactory bulb, hippocampal pyramidal cells, Purkinje and granule cells in the cerebellar cortex, or somatic motoneurons. The distribution of mGluR3 mRNA in particular neurons and glial cells indicates specific roles of mGluR3 in the glutamatergic system of the central nervous system. © 1993 Wiley‐Liss, Inc.
Vibrissal stimulation affects glucose utilization in the trigeminal/somatosensory system of normal rats and rats prenatally exposed to ethanol
Authors: Miller Michael W. , Dow‐Edwards Diana L. 
Published: January 2005

AbstractThe effect of gestational ethanol exposure on stimulus‐induced sensory activity in the trigeminal/somatosensory System was determined. The mature offspring of mothers fed an ethanol‐containing diet (Et) or pair‐fed a nutritionally matched control diet (Ct) were examined. The C‐row mystacial whiskers were stimulated. Glucose utilization in the principal sensory nucleus of the trigeminal nerve (PSN), ventrobasal thalamus, and somatosensory cortex was determined with [14C]2‐deoxyglucose autoradiography.In Ct‐ and Et‐treated rats, whisker stimulation increased glucose utilization in C‐row barrel(oid)s in the left PSN, the right ventrobasal thalamus, and the right somatosensory cortex. The rate of glucose utilization in the C‐row barrel(oid)s and in nonstimulated regions was lower in the Et‐treated rats than in controls. In the cortices of Ct‐treated rats, the activity in the C‐row barrels on the right side was greater than in the right nonbarrel somatosensory cortex. Et‐treated rats also exhibited an increase in glucose utilization, albeit smaller than that in the Ct‐treated rats. In contrast, the glucose utilization in the left B‐ and C‐row barrels of Ct‐treated rats was decreased. No such decrease was evident in the left cortices of Et‐treated rats.Thus, stroking whiskers stimulates the activity of sites in the trigeminal/somatosensory system. In cortex, the definition of these sites is emphasized by depressed activity, i.e., “surround” inhibition, in sites connected via callosal or corticocortical projections. Prenatal exposure to ethanol depresses the metabolic activity regardless of the physiological state; however, the “surround” inhibition of cortical activity is eliminated by prenatal exposure to ethanol through an exuberant projection. © 1993 Wiley‐Liss, Inc.