bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological study of flight motor neurons in the cricket
Authors: Wang S. , Robertson R. M. 
Published: January 2005

AbstractThe motor innervation of the major flight muscles powering the fore‐ and hindwings of the cricket Teleogryllus oceanicus was investigated. The morphology of the motor neurons was determined by filling them via their axons in the periphery with either Lucifer Yellow or cobalt chloride followed by silver intensification. Details of the location of branches of motor neurons within the ganglion were obtained by serially sectioning ganglia containing filled neurons. For each flight muscle at least two motor neurons were found. The somata of motor neurons were located in two clusters in the ganglion, the anterior lateral cluster and the posterior lateral cluster. Motor neurons in the same cluster had similar morphologies. Most of the arborizations of these motor neurons were in the dorsal neuropil with a few branches in the lateral intermediate neuropil. The morphology of flight motor neurons was compared with the morphology of leg motor neurons in consideration of the possible functional organization of the ganglion. A comparison was made between motor neurons innervating homologous muscles of the cricket and the locust to determine the extent of the difference between the flight systems of these two groups.
Glycine‐immunoreactive projection of the cat lateral superior olive: Possible role in midbrain ear dominance
Authors: Marie Richard L. Saint , Ostapoff E.‐Michael , Morest D. Kent , Wenthold Robert J. 
Published: January 2005

AbstractNeurons in the lateral superior olive are optimally excited by stimulation of the ipsilateral ear, as are those in the inferior colliculus by stimulation of the contralateral ear. This reversal of ear dominance may result, in part, from distinct crossed excitatory and uncrossed inhibitory pathways ascending from the lateral superior olive. To explore this possibility, immunoreactivity for two putative inhibitory neurotransmitters, glycine and GABA, was examined in projection neurons that retrogradely transported horseradish peroxidase from the cat inferior colliculus.The results suggest that the projection from the lateral superior olive can be segregated, immunocytochemically, into three components: (1) a crossed, glycine‐negative (−) projection; (2) an uncrossed, glycine‐positive (+) projection; and (3) an uncrossed, glycine(−) projection. Additional evidence suggests that the terminal fields of the two uncrossed projections may distribute differently within the inferior colliculus. Glycine(+) or glycine(−) projection neurons, crossed or uncrossed, do not differ in the size, shape, or location of their somata. However, most glycine(−) neurons are heavily encrusted with glycine(+) endings; glycine(+) neurons have 40–60% fewer of these endings. Glycine(−) neurons located in the lateral limb have fewer glycine(+) perisomatic endings than those in the medial limb. Few projection neurons are GABA(+), and GABA(+) perisomatic endings are rare in the lateral superior olive.Thus, there is a heavy uncrossed projection from the cat lateral superior olive to the inferior colliculus that may be glycinergic and inhibitory. Furthermore, there is a bilateral projection that is not glycinergic or GABAergic, which may be excitatory. The potential contribution of these pathways to contralateral ear dominance in the inferior colliculus is discussed.
Topographical organization of the projections from the reticular thalamic nucleus to the intralaminar and medial thalamic nuclei in the cat
Authors: Velayos J. L. , Jiménez‐Castellanos J. , Reinoso‐Suárez F. 
Published: January 2005

AbstractThe topography of the projections from the reticular nucleus of the thalamus (RT) to the intralaminar and medial thalamic nuclei were studied in the cat by the method of retrograde transport of horseradish peroxidase (HRP). Single small injections of the enzyme were made in the different intralaminar nuclei‐mediodorsal, ventromedial, midline, and habenular‐and in anterior group nuclei. The location and density of the neuronal labeling in the different parts of the RT were studied in each case.Our results show that 1) after injections located in all the nuclei here studied, a consistent number of labeled neurons were found in the RT, except for the injections in the lateral habenula and the anterior thalamic nuclear complex, both of which did not label neurons in the RT. 2) Among the other thalamic nuclei here studied, the most medially situated receive less numerous RT projections than those most laterally located. 3) Injections in all the nuclei studied gave rise to a cellular labeling in the anterior sectors of the RT, except for the anterior nuclear group and the lateral habenula. The projections from the rostral pole of the RT were topographically mediolaterally organized. 4) The anterodorsal part of the pregeniculate sector of the RT projects upon the large‐called part of the lateral central nucleus and to a lesser extent upon the paracentral, centromedian, and ventromedial nuclei, the anterior part of the lateral central nucleus, and the lateral band of the mediodorsal nucleus. The posterodorsal part of the RT pregeniculate sector only projects to the large‐celled part of the lateral central nucleus. The dorsal portion of the posteroventral part of the RT pregeniculate sector also projects upon the large‐celled part of the lateral central nucleus; its ventral portion projects to the ventromedial nucleus, the posterior part of the paracentral nucleus, the lateral band of the mediodorsal nucleus, and the centromedian nucleus. 5) The infrageniculate sector of the RT projects to the posterior part of the ventromedial nucleus. A weaker projection to the large‐celled part of the lateral central nucleus, the centromedian nucleus, and the lateral band of the mediodorsal nucleus was also observed. 6) The ventral lateral geniculate nucleus projects upon the large‐celled part of the lateral central nucleus, the lateral band of the mediodorsal nucleus, and the ventromedial nucleus.All these findings suggest an important modulatory action of the RT on the activity of the thalamic nuclei considered here.
Organization of the GABAergic system in the rat hippocampal formation: A quantitative immunocytochemical study
Authors: Woodson Walter , Nitecka Liliana , Ben‐Ari Yehezkel 
Published: January 2005

AbstractSpecific antibodies against gamma aminobutyric acid (GABA) and glutamic acid decarboxylase (GAD) were used to study the organization of the GABAergic system in the rat hippocampal formation. Both the number of GABA‐like‐immunoreactive (Li) somata and neuropil density were assessed in semithin sections. Cell counts revealed that approximately 11% of the hippocampal neuronal population showed GABA‐Li within the various planes of section.Each layer in the hippocampal formation had a characteristic organization of GABA‐Li elements. In Ammon's horn, 80–95% of the neuronal somata within the apical and basal dendritic regions were GABA‐Li positive. Within the pyramidal cell layer 5–8% of the cells were GABA‐Li in the CA1 to CA3 subfields of Ammon's horn and only 3% were GABA‐Li within that portion of the pyramidal cell layer that inserts into the hilus. Only slight differences in the density of the GABA‐Li neuropil were observed within the CA1‐CA3 dendritic regions. Restricted to the stratum lucidum was a dense band of GABA‐Li label. Counts of immunoreactive grains localized on the perimeter of pyramidal (CA1‐CA3) and granule somata revealed more terminal boutons on the CA3 cells than on CA1 and granule neuronal somata.A topographical distribution of GABA‐Li somata and neuropil was found in the fascia dentata: There the label particularly concerned its suprapyramidal and rostrolateral portions. Approximately 40% of neurons in the molecular layer, 60% in the polymorph layer, and 18% within the hilar region were GABA‐Li. Within the granule cell layer only 2% of the neurons were GABA‐Li positive. Distinct differences in the density of the GABA‐Li neuropil were present in the molecular, pericellular granular, and hilar regions of the fascia dentata.While the morphology of GABA‐Li neuronal somata varied according to their hippocampal layer, the most heterogeneous cell types were found in the regio inferior of the hippocampus. There we have identified neurons that are reminiscent of the inferior region interneuron described in Golgi material by Amaral and Woodward (Brain Res. 124:225–236, '77). Moreover, particularly in the sagittal plane, we have identified oval, triangular, and round cells and that have processes oriented in a parallel arrangement, appearing to be aligned along the granule cell mossy fibers.
Comparative quantitative study of the hippocampal region of two closely related species of wild mice: Interspecific and intraspecific variations in volumes of hippocampal components
Authors: Slomianka L. , West M. J. 
Published: January 2005

AbstractTo investigate the structural changes in the hippocampal region (subiculum, Ammon's horn, and area dentata) associated with speciation, the volumes of homologous components of this region of the forebrain were compared in the two closely related murine rodent species, Apodemus flavicollis (yellow‐necked wood mice) and A. sylvaticus (long‐tailed field mice), and in two geographically separated groups of A. sylvaticus.With the exception of the mossy fiber zone, no significant differences were found in the relative sizes of the components of Ammon's horn. Significant interspecific differences were found in the deep subiculum, in the intermediate (medial perforant path) and deep (commissural‐associational) zones of the molecular layer of the area dentata, and in the hilus. A significant intraspecific difference was found in the combined intermediate and superficial (medial and lateral perforant path) zone of the dentate molecular layer.Differences found in the relative size of the hilus and the mossy fiber zone of Ammon's horn were complementary in that the combined volumes of these zones, which are both terminal fields of dentate granule cells, did not differ in the two species. This finding provides evidence that the distribution of the terminal field of a projection system can be altered while the size of the terminal field is maintained.Within the hippocampal region, components of Ammon's horn appear well suited for quantitative comparative studies that span taxonomic units beyond the species level. In agreement with previous quantitative studies, differences in the volumes of components of Ammon's horn found in species of different orders are more likely to reflect phylogenetic trends rather than changes resulting from specializations of the particular species used. This is not true for the subiculum and the components of the area dentata.Experimentally induced changes in the connectivity of the hippocampal region are discussed in terms of the structural changes which may be responsible for the quantitative differences observed between the two species studied here.
Distribution of radioactive leucine following uptake by olfactory sensory neurons in normal and heteromorphic crayfish antennules
Authors: Mellon DeForest , Tuten H. Robert , Redick Jan 
Published: January 2005

AbstractSurgical excision of one of the compound eyes from juvenile crayfish leads to the regeneration of a heteromorphic antennule in 30% of the cases. Most of the heteromorphic antennules generated this way are bifurcate appendages possessing morphologically distinct medial and lateral branches. These structures are identical to the internal and external flagella of the normal antennules, and the homolog of the external flagellum bears aesthetascs supplied by olfactory sensory neurons. Autoradiographic analysis of the brain following exposure of heteromorphic antennules to tritiated leucine indicates that the supernumerary sensory axons transport the labeled amino acid into their central terminals at appropriate target locations within the ipsilateral olfactory lobe. The data suggest that olfactory input from heteromorphic antennules is incorporated into the organized central projection of olfactory afferents from the normal antennule.
Modification of left‐right pairing during the development of individual crest synapses in the rat interpeduncular nucleus
Authors: Lenn Nicholas J. , Whitmore Leanna 
Published: January 2005

AbstractThe synaptic organization of the rat interpeduncular nucleus is highly ordered in the normal adult. By 90 days of age, 90% of crest synapses in its intermediate subnuclei are formed by two cholinergic endings, one from each medial habenula. Stereological calculation of the number of crest synapses per intermediate subnucleus, based on total samples of crest synapses in 3–4 sections through the subnucleus, allows comparisons of afferent pairing among ages without interference by other developmental changes. Between 21 and 90 days of age, the total number of crest synapses per intermediate subnucleus increases tenfold (p ≤ 10−8), from 90,000 at 21 days of age, through 130,000 at 28 days, 440,000 at 45 days, to 1,000,000 at 90 days. The volume of the intermediate subnucleus increases fivefold during the same interval.Electron microscopic degeneration was used to estimate the pairing of left and right habenula afferents at crest synapses at the same ages. Through 21 days of age, only one‐third of crest synapses are formed with pairing of one left and one right medial habenula afferent, whereas two‐third have both afferent endings arising from the same medial habenula. At 28 days of age left‐right pairing has increased to 43%, and at 45 days of age 53%, or 240,000, are so paired. The number of same‐side paired crest synapses at 45 days, 210,000, is 3.5 times the number so paired at 21 days (p = .003). This indicates continued formation of considerable numbers of crest synapses with this transient mode of pairing as late as 45 days of age. Since the number with same‐side pairing in the adult, 100,000, is half the number at 45 days (p ≤ 10 −8), remodeling of afferent pairing must continue to be an important process in the development of interpeduncular nucleus throughout the period of synaptogenesis. Conversely, the data are inconsistent with the principal alternative, a marked change in synapse formation after 21 days of age such that newly forming crest synapses are initially left‐right paired.The remodeling may involve any of several modes of synapse elimination and/or altered pairing. It appears to be similar to remodeling observed in a number of other systems, although these have rarely addressed connectivity at the level of individual synapses. Since the cellular and molecular mechanisms of remodeling in general remain to be discovered, a system where these processes can be experimentally approached in terms of their level of action at individual synaptic sites may facilitate analysis.
Topography and morphology of retinal ganglion cells in the coral trout Plectropoma leopardus (Serranidae): A retrograde cobaltous‐lysine study
Authors: Collin Shaun P. 
Published: January 2005

AbstractThe retinal topography of the adult coral trout Plectropoma leopardus (Serranidae, Perciformes) is examined in Nissl‐stained material and confirmed by means of retrograde labelling with cobalt‐lysine from the optic nerve. Concentric isodensity contours surround a temporoventral area centralis of over 1.5 × 104 cells per mm2 which lies ventral of the elongated optic nerve head. Peripheral densities of ganglion cells fall to less than 0.25 × 104 cells per mm2. A total of 1.17 × 105 ganglion cells is found over the entire retina. Silver intensifications of cobalt‐lysine‐stained cells allow a detailed analysis of ganglion cell morphology. Soma and dendritic field size increase with eccentricity, and within the confines of the area centralis only the smallest cell size is found. Dendritic arbors of peripheral ganglion cells are all oriented parallel to the retinal margin with an axon lying close to the vitreous humor. Nine classes of cells are characterized on the criteria of soma size, dendritic field size, primary and secondary branching patterns, soma position, and dendritic termination areas. Possible morphological homologies with ganglion cells of other teleosts are also discussed.
Bouton ultrastructure and synaptic growth in a frog autonomic ganglion
Authors: Streichert Laura C. , Sargent Peter B. 
Published: January 2005

AbstractPostmetamorphic growth in the frog, Xenopus laevis, is accompanied by an increase both in the size of autonomic neurons in the heart and in the number of synaptic boutons that contact their surface. To determine whether the properties of individual boutons change as their number increases, serial‐section electron microscopy was used to examine bouton ultrastructure at the end of metamorphosis and in the adult. The area of bouton contact, number of active zones per bouton, active zone size, percent of bouton area occupied by active zone, and vesicle density were examined. No differences were found between the two bouton populations for any of the parameters examined. These results support the hypothesis that boutons are structural units of synaptic growth, whereby the total area of synaptic contact increases through the addition of boutons without a change in their morphological properties.
Topographic organization of the central projections of the spiral ganglion in cats
Authors: Leake Patricia A. , Snyder Russell L. 
Published: January 2005

AbstractThe morphological organization of inputs from restricted sectors of the cat cochlear spiral ganglion into the cochlear nucleus was studied by making focal extracellular injections of horseradish peroxidase (HRP) into the spiral ganglion. Injections resulted in Golgi‐like labeling of a small cluster of spiral ganglion cells and their peripheral and central axons.Large injections involved most of the cells within Rosenthal's canal in sectors of the spiral ganglion innervating ≥;1 mm of the basilar membrane and resulted in narrow, complete laminae of labeled axons and preterminal fields within each cochlear nucleus subdivision. The positions of these bands were consistent with the “isofrequency laminae” appropriate for the frequencies represented at the injection sites, with high frequency laminae situated more dorsally, and lower frequencies progressively more ventral. A discrete projection to the small cell cap area was observed that was discontinuous with the main projection laminae in the ventral cochlear nuclei (VCN). In the dorsal cochlear nucleus, projecting fibers and terminals were excluded from the molecular cell layer. No labeled fibers entered the granule cell areas.In contrast to larger injections, very small HRP deposits labeled only part of an isofrequency lamina. Specifically, injections restricted to the scala tympani aspect of the spiral ganglion labeled only the lateral part of VCN isofrequency laminae, whereas injections limited to the scala vestibuli aspect of the ganglion labeled the medial aspect of the isofrequency planes. Thus these data indicate a previously unrecognized topographic representation of the vertical dimension of the spiral ganglion across VCN isofrequency laminae. Some posible functional implications of this projection organization are discussed.
Thalamic connections of the cortex of the superior temporal sulcus in the rhesus monkey
Authors: Yeterian Edward H. , Pandya Deepak N. 
Published: January 2005

AbstractThe thalamocortical connections of the superior temporal sulcus (STS) were studied by means of the WGA‐HRP retrograde tracing technique. The results indicate that the distribution of thalamic projections varies along the rostral‐caudal dimension of the STS. Thus the rostral portion of the upper bank receives input primarily from the medialmost portion of the medial pulvinar (PM) nucleus. The middle region of the upper bank receives projections from medial and central portions of the PM nucleus, and also from the oral pulvinar, limitans, suprageniculate, medial geniculate, and dorsomedial nuclei. The cortex of the caudal portion of the upper bank has basically similar thalamic input; however, the projections from the PM nucleus originate in central and lateral portions. Additionally, there are projections from the lateral pulvinar (PL), ventroposterolateral, central lateral, parafascicular, and paracentral nuclei. In contrast to the dorsal bank, the cortex of the ventral bank of the STS receives somewhat different and less extensive thalamic input. The rostral portion of the lower bank receives projections only from the ventromedial sector of the PM nucleus whereas the middle portion of the lower bank receives projections from the PL and the inferior pulvinar nuclei as well as from the PM nucleus.The upper bank of the STS, on the basis of physiological and anatomical studies (Jones and Powell, '70; Seltzer and Pandya, '78; Gross et al., '81; Baylis et al., '87), has been shown to contain multimodal areas. The present data indicate that the multimodal region of the STS has a preferential relationship with the central sector of the PM nucleus.
Enzyme‐histochemical demonstration of microglial cells in the adult and postnatal rabbit retina
Authors: Schnitzer Jutta 
Published: January 2005

AbstractEnzyme‐histochemical methods for thiamine pyrophosphatase (TPPase) and nucleoside diphosphatase (NDPase) were applied to wholemounted rabbit retinae to demonstrate the shape and distribution of microglial cells in early postnatal and adult animals. At birth, microglial cells were already present in the entire retina. They acquired their adult “resting shape” during the first 3 postnatal weeks. Early postnatally labeled microglial cells were scattered throughout the nerve fiber layer, the inner plexiform layer, and the outer plexiform layer (OPL); at adulthood, they were not detected in the OPL. Nissl‐stained retinae revealed that the number of microglial cells continuously increased during postnatal development. The same Nissl‐stained preparations were used to evaluate the topography of degenerating cells in the developing postnatal retina of the rabbit. Large numbers of degenerating pyknotic cells were observed throughout the entire retinal ganglion cell layer during the first postnatal week. Later their number decreased, and from the third postnatal week onward degenerating cells were rare. Also discussed is that the emergence of microglial cells during development may be related to cell death, whereas at adulthood the function(s) of microglial cells remains obscure.Evidence for the blood‐derived origin of microglia was not obtained in this study. It is argued here that if this mode of development, which has been demonstrated for other species, is also applied to the rabbit retina, then microglia would have to migrate over considerable distances, since, postnatally, the rabbit retina is avascular for more than 1 week.