bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal modifications of the dendritic tree of cells in the inferior coliicuius of the cat. A quantitative Golgi analysis
Authors: Meininger Vincent , Baudrimont Marie 
Published: January 2005

AbstractPostnatal modifications of dendrites have been quantitatively studied by network analysis of the dendritic tree in the two central nuclei of the inferior colliculus in the cat. This analysis revealed cells with two types of branching patterns suggesting two different modes of growth. The predominant pattern is characterized by dichotomous branching on random segments (DR cells). However, a purely collateral branching pattern is particular to certain cells (CB cells). These two branching patterns were found in both nuclei of the IC in adult and young cats, but the exact significance of these two cell types remains unclear.The dendritic trees ofcells in kittens differed from those ofthe adult cat. Also, the types of modification were different in the two functionally distinct nuclei of the inferior colliculus that we studied. The most dramatic modifications were observed in the dendritic tree of DR cells in the central nucleus, which receives fibers from the auditory nuclei in the brainstem. Two parameters were modified: the mean number of terminal segments and the mean total length of segments. Both parameters increased in the sagittal plane and decreased in the frontal plane. These modifications indicate a reorientation of the dendritic tree in the sagittal plane, along the incoming axons from the auditory nuclei. As these afferents become functionally mature only after birth, this spatial remodeling of the dendrites seems closely related to functional maturation of secondary auditory axons. In the dorsomedial nucleus that receives fibers from the auditory cortices, the dendritic tree of DR cells also undergoes spatial reorientation. This is more evident in the horizontal plane and with respect to the incoming axons.Our results suggest that the characteristic orientation of the dendritic tree of cells observed in the inferior colliculus of the adult cat is established only after the first postnatal weeks. This orientation seems to result from an active process of remodeling concomitant with the functional maturation of afferents, a fact already established for various cell types in the nervous system.
The distribution of nine peptides in rat spinal cord with special emphasis on the substantia gelatinosa and on the area around the central canal (laminaX)
Authors: Gibson Sally J. , Polak Julia M. , Bloom Stephen R. , Wall Patrick D. 
Published: January 2005

AbstractThe comparative distribution of nine peptides was examined in the L4 segment of the rat cord using the peroxidase antiperoxidase technique. The peptides examined were substance P, neurotensin, cholecystokinin, methionine‐enkephalin, oxytocin, neurophysin, adrenocorticotrophin, thyrotropin releasing hormone, and vasoactive intestinal polypeptide. No transport blocking agents were used and in spite of this cell bodies containing substance P, neurotensin, cholecystokinin, and methionine‐enkephalin were observed. All peptides except for thyrotropin releasing hormone were observed in fibers in laminae I and II. All peptides were present in the area around the central canal, laminaX. Each peptide had its own characteristic distribution within fibers in the gray and white matter.
The origin of the spinomesencephalic tract in the rat: An anatomical study using the retrograde transport of horseradish peroxidase
Authors: Menétrey Daniel , Chaouch Athmane , Binder Denise , Besson Jean Marie 
Published: January 2005

AbstractAn anatomical technique based on the retrograde transport of horseradish peroxidase (HRP) was used to investigate the projections of spinal cord neurons to the mesencephalic tegmentum in the rat. Restricted unilateral injections were confined to central grey, cuneiformis area, and superior colliculus. Injections into all these loci produced labeling in similar spinal areas. Only quantitative differences were noted.In the spinal grey matter, numerous labeled cells were regularly encountered in the marginal zone, the lateral part of the neck of the dorsal horn, and the dorsal grey commissure. Projections from the marginal zone and neck of the dorsal horn were predominantly contralateral. In the white matter, a pronounced bilateral labeling was observed in the nucleus of the dorsolateral funiculus, thus confirming our previous electrophysiological findings (Menétrey et al., '80). This distribution of labeled cells was commonly observed throughout the whole length of the cord. Additional sites of projecting cells have also been identified at the most rostral levels (obex, C1, C2). They mostly derived from spinal extensions of the dorsal column nuclei and lateral cervical nucleus contralaterally; from the lateral ventral horns bilaterally and from the nucleus commissuralis ipsilaterally.This study is thus a clear confirmation that the mesencephalic tegmentum constitutes a target for various somatosensory inputs originating from spinal cord, dorsal column nuclei, and lateral cervical nucleus. Moreover, from these results together with those obtained for the spinothalamic tract in the rat, it appears that marginal and dorsolateral funiculus neurons preferentially project to the mesencephalic tegmentum. The importance of marginal zone projections underlines the involvement of the spinomesencephalic tract in pain mechanisms.
A quantitative analysis of the ipsilateral retinocollicular projection in the cat: An EM degeneration and EM autoradiographic study
Authors: Behan Mary 
Published: January 2005

AbstractThe ipsilateral projection to the binocular segment of the superior colliculus in the cat was quantified by means of electron microscopic (EM) degeneration and electron microscopic autoradiography. Because of the patchy distribution of ipsilateral terminals, contiguous samples were taken across the mediolateral extent of the colliculus. The results from both EM degeneration and EM autoradiography are in substantial agreement: In the binocular segment, the ipsilateral projection represents 5.3% and 5.6%, respectively, of the total retinal input to the superior colliculus. As the contralateral projection extends over the whole colliculus but is greatest in the caudal region, while the ipsilateral projection is restricted to the middle one‐third of the colliculus, it follows that the total ipsilateral retinocollicular projection is less than earlier estimates (5–10%, Kanaseki and Sprague, '74) and probably closer to 1%, as suggested by Sterling ('73) on the basis of an electron microscopic degeneration study. A significant finding is that there are many more terminals per axon in the contralateral than in the ipsilateral superficial gray. The ratio of degenerated terminals in SGS1 and SGS2 to degenerated axons in SGS3 is 3.1 contralaterally, while in the ipsilateral colliculus the figure is 1.2. This may reflect a difference in the arborization pattern of Y‐type and W‐type retinal ganglion cells in the colliculus.
Electron microscopic immunocytochemical localization of tyrosine hydroxylase in the area postrema of rat
Authors: Armstrong D. M. , Pickel V. M. , Joh T. H. , Reis D. J. 
Published: January 2005

AbstractThe ultrastructural morphology and specialized neuronal, vascular, and ventricular associations of tyrosine hydroxylase‐labeled neurons are examined within the area postrema of rat brain. Specific antiserum to the purified enzyme is localized throughout the rostrocaudal and dorsoventral extent of the area postrema by means of the peroxidase‐antiperoxidase technique. In all regions, peroxidase immunoreactivity for tyrosine hydroxylase is distributed throughout the cytoplasm of selectively labeled neuronal perikarya and processes. The perikarya contain a large nucleus, infolded nuclear membrane, numerous cytoplasmic organelles, and form axosomatic synapses with unlabeled terminals. The majority of the labeled processes are dendrites, which contain ribosomes, microtubules, mitochondria, and scattered vesicles. These dendrites are postsynaptic to unlabeled axon terminals and show membrane specializations with other labeled dendrites and perikarya. In contrast to dendrites, peroxidase‐labeled profiles clearly distinguished as axons or axon terminals are sparse and never show membrane specializations with other neuronal or nonneuronal structures within the area postrema. Numerous large processes which could be either axons or dendrites are associated with blood vessels and the ventricular surface of the area postrema. With respect to blood vessels, processes are located either in direct apposition to the external glial membrane, or less frequently, within the perivascular space. The ventricular processes are either associated with blood vessels in the subpial space or distributed among the cilia and villi at the anterior margins of the area postrema. The neuronal and nonneuronal associations of the tyrosine hydroxylase‐labeled processes are consistent with a receptor or chemosensor function for catecholamines in this circumventricular organ.
Electrophysiological response properties of spinoreticular neurons in the monkey
Authors: Haber L. H. , Moore B. D. , Willis W. D. 
Published: January 2005

AbstractExtracellular recordings were made from 29 spinoreticular cells in the spinal cords of anesthetized monkeys. The cells were in either the cervicalor the lumbar enlargement, and they were identified by antidromic activation from the medial part of the pontomedullary reticular formation. More spinoreticular neurons were sampled in the cervical than in the lumbar cord. Most of the cells were contralateral to the side from which antidromic activation was observed, but a higher proportion of the spinoreticular neurons inthe cervical enlargement than in the lumbar enlargement was ipsilateral to the antidromic stimulus. Three cells in the lumbar cord were antidromicallyactivated not only from the reticular formation but also from the contralateral thalamus, confirming that some spinoreticular projections are formed by collaterals from spinothalamic cells. Most of the spinoreticular neurons were in the ventral horn in laminae VII and VIII, although a few were in laminae IV‐VI. Nearly half of the spinoreticular cells in the sample could not be activated by any form of peripheral stimulation tested. The other cells could be activated by stimulation of receptive fields that varied from small to large, that were sometimes bilateral regions of the skin or of deep tissues. Although some spinoreticular cells could be classified as low threshold or wide dynamic range, the largest proportion were high threshold, requiring noxious stimulation for their activation. Descending volleys resulting from stimulation in the reticular formation could often be shown to inhibit or to excite spinoreticular neurons. It can be concluded that at leastsome spinoreticular neurons may play a role in nociception.
The contribution of late‐generated neurons to the callosal projection in the rat: A study with prenatal x‐irradiation
Authors: Jensen Karl F. , Altman Joseph 
Published: January 2005

AbstractStudies utilizing horseradish peroxidase tracing methods have suggested that there are species differences in the relative contribution of the different neocortical layers to the callosal projection. The present investigation utilized x‐irradiation at different gestational ages to eliminate the late‐generated neurons of the rat neocortex. The caudorostral gradient of reduction in the neuronal population of the supragranular layers is closely correlated with the gradient of reduction in the size of the corpus callosum. Furthermore, the callosal projection is absent in anteroposterior cortical segments in which the development of the supragranular layers was prevented without a reduction of the number of neurons in the infragranular layers of the neocortex. These results indicate that late‐generated neurons residing primarily in the supragranular layers are essential for the formation of the corpus callosum.
The postnatal development of the substantia nigra: A light and electron microscopy study
Authors: Phelps Patricia E. , Adinolfi Anthony M. 
Published: January 2005

AbstractThe early postnatal development of neurons, dendrites, and synaptic connectivity in kitten substantia nigra (SN) was studied by light and electron microscopy. The compact and reticular divisions of the SN are present at birth but boundaries are indistinct. Most nigral neurons stain deeply in routine histological sections and their diameters increase slightly with age. Ultrastructurally, cell bodies are characterized by eccentrically located and often invaginated nuclei surrounded by cytoplasm rich in well‐formed or‐ganelles. Axosomatic synapses are infrequent and cell surfaces are enveloped by glial processes. Immature dendritic features, including growth cones and filiform processes, are commonly observed during the first 10 days. Gradually the dendritic profiles elongate and thicken and contours become smoother, retaining only scattered spinelike appendages.Clear examples of the three synaptic types described in cat are found in newborn kittens, but immature terminals contain fewer synaptic vesicles and mitochondria. Approximately 90% of synapses present at birth in both nigra subdivisions are Type I, which contain large pleomorphic vesicles and contact dendrites symmetrically. Asymmetrical contacts characterize most of the remaining definable synapses. The postnatal increase in synaptic connectivity, which was estimated from random photographs of pars reticulata neuropil, is twofold during the first 50 days of life. Initially young dendrites are enveloped by glia and then gradually become ensheathed by axon terminals. Synaptogenesis in pars reticulata reflects the postnatal increase of neostriatal inputs to this subdivision and can be correlated with functional changes in strionigral connectivity.
The locations of stapedius and tensor tympani motoneurons in the cat
Authors: Shaw Marjorie D. , Baker Robert 
Published: January 2005

AbstractThe numbers and locations of motoneurons to the Stapedius and tensor tympani muscles were determined by retrograde transport of horseradish peroxidase. Stapedius motoneurons lay outside the traditionally recognized facial nucleus, in several distinct locations: (1) in the interface between the facial nucleus and the superior olive; (2) in a thin, scattered lamina of somewhat smaller cells spread dorsal to the facial nucleus; and (3) in a cluster located ventromedial to the rostral third of the facial nucleus. Some cells also lay dorsal to the superior olive or scattered in the reticular formation, just medial to the descending loop of the facial nerve. Tensor tympani motoneurons also lay outside the traditionally recognized trigeminal motor nucleus, in an areajust ventral to it. Both motoneuron pools were large, producing in‐nervation ratios that establish Stapedius and tensor tympani among the most finely innervated muscles yet studied. The degree of intermingling of large and small cells in these pools may explain, in part, why it has been easier to identify slow muscle fibers physiologically in tensor tympani than in Stapedius.
NADPH‐diaphorase: A selective histochemical marker for striatal neurons containing both somatostatin‐ and avian pancreatic polypeptide (APP)‐like immunoreactivities
Authors: Vincent S.R. , Johansson O. , Hökfelt T. , Skirboll L. , Elde R. P. , Terenius L. , Kimmel J. , Goldstein M. 
Published: January 2005

AbstractCertain neurons in the brain are specifically and intensely stained by a histochemical method which demonstrates nicotinamide adenine dinucleo‐tide phosphate NADPH‐diaphorase activity. The cell types containing this enzyme in certain areas of the rat forebrain were examined by combining NADPH‐diaphorase histochemistry with the indirect immunofluorescence technique. Neurons containing somatostatin‐ or avian pancreatic polypep‐tide (APP)‐like immunoreactivities were found throughout the forebrain including the striatum and neocortex. These two neuropeptides were also found to coexist in many telencephalic neurons. After photography, the sections processed for immunohistochemistry were stained for NADPH‐diaphorase activity by a histochemical method. It was found that within the striatum all of the neurons that were selectively stained by this technique also contained both somatostatin‐ and APP‐like immunoreactivities. Also in the neocortex NADPH‐diaphorase was found only in those neurons displaying somatostatin‐ or APP‐like immunoreactivity. In other brain regions such as the nucleus laterodorsalis tegmenti, NADPH‐diaphorase‐containing cells did not contain these neuropeptides.The results indicate that NADPH‐diaphorase histochemistry provides a simple, reliable, histochemical method to demonstrate those striatal neurons in which somatostatin‐ and APP‐like immunoreactivities coexist. The selective occurrence of this enzyme within these neurons may provide a useful target for pharmacological studies of these neuropeptide‐containing cells.
The distribution of neocortical projection neurons in the locus coeruleus
Authors: Waterhouse Barry D. , Lin Chia Sheng , Burne Richard A. , Woodward Donald J. 
Published: January 2005

AbstractThe present study was conducted to examine the spatial organization of locus coeruleus (LC) neurons that project to rat cerebral cortex. Long‐Evans hooded rats received unilateral pressure injections of horseradish peroxi‐dase (HRP) in either frontal (n = 6) or sensorimotor (n = 11) or occipital (n = 7) cortex to determine the intranuclear location of LC neurons which project to specific neocortical regions. Coronal and sagittal sections (40–100 μm) through the LC were examined by light microscopy after carrying out the tetramethyl benzidine reaction and staining with neutral red. The locations of retrogradely labeled cells were recorded on a three‐dimensional biological coordinate system maintained by a computer linked to the light microscope. LC neurons labeled from cerebrocortical injections of HRP were primarily located in the ipsilateral and to a lesser extent (fewer than 5% of total labeled cells) in the contralateral nucleus. Coeruleocortical projection neurons were concentrated in the caudal three‐fifths of the dorsal division of the ipsilateral LC. Within this portion of the nucleus, HRP‐filled neurons were distributed so that individual groups of cells projecting to occipital or sensorimotor or frontal cortex were coarsely aligned in a dorsal to ventral array, respectively. Moreover, in the sagittal plane of the nucleus the pattern of labeling was spatially graded so that the subset of neurons projecting to the occipital cortex was displaced more caudally in the LC than the groups of cells sending axons to sensorimotor or frontal cortex. Only the frontal area of the cortex received a projection from both dorsal and ventral divisions of the ipsilateral LC. Computer‐assisted analysis of the data further suggested that neocortical projection neurons in the dorsal LC are loosely organized into two groups which run rostrocaudally through the core of the caudal nucleus. The zone of labeling resulting from injections confined to the neocortical gray matter overlapped with but was not coextensive with that observed following injections into the caudate, hippocampus, and cerebellum. These results suggest that partially overlapping subsets of LC cells might independently influence separate populations of neurons within noradrenergic terminal fields of the neocortex.
Four types of neuron in layer IVab of cat cortical area 17 accumulate 3H‐GABA
Authors: Hamos James E. , Davis Thomas L. , Sterling Peter 
Published: January 2005

AbstractRoughly 10% of the neurons in layer, IVah.of cat area 17 accumulate exogenous 3H‐gamma‐aminobutyric acid (GABA) but how many types of neuron comprise this population was unknown. We characterized these neurons by partial reconstruction of their somas from serial electron microscope autoradiograms and distinguished four types. GABA 1 was large (> 16.5 μm) and dark with a dense distribution of synaptic terminals, substantial geniculate input to the soma, and a moderate accumulation of GABA. GABA 2 was small (< 13 μm) and pale, also with a dense distribution of terminals but without evidence of somatic geniculate input, and a moderate accumulation of GABA. GABA 3 was radially fusiform (20μm × 8 μm) with varicose dendrites, a sparse distribution of synaptic terminals, and a heavy accumulation of GAB A. GAB A 4 was medium in size (15 μm) with a moderate distribution of synaptic terminals and a heavy accumulation of GABA. Reasons are presented for believing that each of these four categories of GABA‐accumulating neuron represents a fundamental cell type.
The effect of forebrain lesions in the neonatal rat: Survival of midbrain dopaminergic neurons and the crossed nigrostriatal projection
Authors: Jaeger C. B. , Joh T. H. , Reis D. J. 
Published: January 2005

AbstractLesions were placed in the striaturn and the olfactory tubercle of 1‐day‐old rat pups. Control and experimental animals were raised to adulthood. Efferent projections of mesencephalic neurons were examined by injecting the retrograde tracers horseradish peroxidase or Fast Blue into the undamaged striata of some experimental animals. The survival of the mesencephalic dopaminergic neurons was monitored by using immunocytochemical localization of tyrosine hydroxylase. Small lesions in the caudate‐putamen had no appreciable effect on the survival of tyrosine hydroxylase‐containing neurons in the mesencephnlon, but the density of dopaminergic terminals adjacent to the lesion increased in the remaining caudate‐putamen. Striatal lesions that involved an estimated area of more than one‐third resulted in loss of dopamine neurons of the substantia nigra compacta. Rostral lesions in the striatum affected mostly rostrally positioned neurons in the substantia nigra. Dorsal lesions of the caudate‐putamen resulted in disappearance of dorsal A9 neurons. Reduction of the A10 and A8 dopamine neuron groups occurred if the neonatal lesions involved the olfactory tubercle and nucleus accumbens. Some tyrosine hydroxylase‐containing neurons persisted even after the largest lesions. These dopaminergic neurons formed a crossed ni‐grostriatal pathway which was confirmed by retrogradely transported tracers. The density of this crossed projection in the adult appeared unaffected by the neonatal lesion.We concluded that dopaminergic neurons form topographically ordered projections with their targets in the newborn rat. Rearrangement of these fibers appeared limited, but compensatory increase of axon terminal density was evident in partially lesioned target areas.