bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efferent projections of the sexually dimorphic area of the gerbil hypothalamus: Anterograde identification and retrograde verification in males and females
Authors: Finn Patricia D. , De Vries Geert J. , Yahr Pauline 
Published: January 2005

AbstractOutputs of the sexually dimorphic area (SDA) of the gerbil hypothalamus were identified by injecting Phaseolus vulgaris‐leucoagglutinin into the medial or lateral SDA (mSDA, ISDA) in males and females. They were verified by injecting Fluoro‐Gold or rhodamine‐labeled beads into over half the areas that contained labeled fibers. Both anterograde and retrograde tracing showed that the mSDA and ISDA project to many of the same sites but often to differing degrees. The mSDA projects more heavily than the ISDA to many of their forebrain targets including the ventral part of the lateral septal nucleus, the bed nucleus of the stria terminalis, the medial tuberal area, and the anteroventral periventricular, arcuate, ventromedial and ventral premammillary nuclei of the hypothalamus. The ISDA projects more heavily than the mSDA to many of their mid‐ and hindbrain targets including the caudal, ventrolateral part of the periaqueductal gray, the retrorubral field, the pedunculopontine tegmental nucleus, and the locus coeruleus. In many other areas of the brain, the projections of the mSDA and ISDA are similar in size. These areas include the substantia innominata, the vascular organ of the lamina terminalis, the anterior amygdela, the posterior hypothalamus, the reuniens and paraventricular nuclei of the thalamus, and the pontine periaqueductal gray lateral to the fourth ventricle. The SDA pars compacta (SDApc), a small cell group embedded in the mSDA of males, projects to many fewer areas than the surrounding mSDA. It was strongly labeled when retrograde tracers were injected into the encapsulated part of the bed nucleus of the stria terminalis, the anteroventral periventricular nucleus, or the mSDA. It was also labeled from the vascular organ of the lamina terminalis, the caudal part of the lateral bed nucleus of the stria terminalis, the ISDA, the area lateral to the mSDA, the arcuate nucleus, the ventral premammillary nucleus, and the ventrolateral part of the ventromedial nucleus of the hypothalamus. Nothing resembling an SDApc was identified during retrograde tracing in females. © 1993 Wiley‐Liss, Inc.
Spinal cord and trigeminal projections to the pontine parabrachial region in the rat as demonstrated with Phaseolus vulgaris leucoagglutinin
Authors: Slugg Robert M. , Light Alan R. 
Published: January 2005

AbstractIn order to determine the regions within the parabrachial nucleus that receive synaptic input from nociceptive regions of the spinal cord and medulla in the rat, we analyzed the “Golgi‐like” labeling produced by anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA‐L) from discrete iontophoretic injections confined to either the superficial dorsal horn of the lumbar spinal cord or to the superficial dorsal horn of the trigeminal nucleus at the level of the obex. Labeled fibers from both the spinal cord and the medulla ascended through the ventral lateral pons and coursed with the ventral spinocerebellar tract toward the parabrachial nuclei. Spinal cord injections led to labeling of fine caliber fibers and en passant and terminal enlargements in the rostral part of the contralateral lateral parabrachial nucleus (PBL), mostly in the central lateral and dorsal lateral subnuclei. Medullary injections revealed fiber and enlargement labeling primarily in the ipsilateral caudal PBL, mostly in the central lateral, external lateral, and medial subnuclei. Injections in both regions resulted in labeled terminations in the Kö;lliker‐Fuse nucleus. These results indicate that the nociceptive regions of the spinal cord and medulla terminate in regions of the parabrachial nucleus that have been associated with autonomic functions because of their interconnections with the hypothalamus, brainstem cardiovascular and respiratory control centers, and the amygdala. © 1994 Wiley‐Liss, Inc.
Development of the dendritic fields of layer 3 pyramidal cells in the kitten's visual cortex
Authors: Zec Nataša , Tieman Suzannah Bliss 
Published: January 2005

AbstractThe cat's visual cortex is immature at birth and undergoes extensive postnatal development. For example, cells of layers 2 and 3 do not complete migration until about 3 weeks after birth. Despite the importance of dendritic growth for synaptic and functional development, there have been few studies of dendritic development in the cat's visual cortex to correlate with numerous studies of functional and synaptic development. Accordingly, we used the Golgi method to study the development of the dendrites of layer 3 pyramidal cells in the visual cortex of a series of cats ranging in age from 2 days to 3 years. Blocks of visual cortex were impregnated by the Golgi‐Kopsch method and sectioned in the tangential plane. Layer 3 pyramidal cells were drawn with a camera lucida and analyzed by Sholl diagrams and vector addition. In kittens < 1 week old, these cells were very immature, with only an apical dendrite and no basal dendrites. Basal dendrites appeared during the second week. By 2 weeks, all of the basal dendrites had emerged from the soma, but they had few branches and were tipped with growth cones. By 4 weeks, they had finished branching but continued to grow in length until, by 5 weeks, they reached their adult size. Examination of the basal dendritic fields in the tangential plane revealed that the dendritic fields were more elongated at 2 weeks than at later ages, perhaps because of their smaller size. The distribution of dendritic field orientations was uniform at all ages except 3 and 4 weeks, when there was a preponderance of fields oriented in the rostrocaudal direction. Because dendritic growth and branching occurred very rapidly over a period that precedes and overlaps with the peak periods of synaptogenesis and of sensitivity to the effects of early visual experience, they may depend on afferent visual activity. The early emergence of primary dendrites, however, suggests that this process is independent of afferent activity. The coincident timing of dendritic branching with the presence of dendritic growth cones suggests that branching may occur at growth cones. © 1994 Wiley‐Liss, Inc.
Pyramidal neurons in layer 5 of the rat visual cortex. III. Differential maturation of axon targeting, dendritic morphology, and electrophysiological properties
Authors: Kasper Ekkehard M. , Lübke Joachim , Larkman Alan U. , Blakemore Colin 
Published: January 2005

AbstractThis paper describes the early morphological and physiological development of pyramidal neurons in layer 5 of the rat visual cortex in relation to the targets chosen by their axons. Cells were prelabeled by retrograde transport from the superior colliculus or the contralateral visual cortex and intracellularly injected either in fixed slices or after recording in living slices. In the adult, corticotectal cells have thick apical dendrites with an extensive terminal arborization extending into layer 1, and fire characteristic bursts of action potentials when injected with a depolarizing current; interhemispheric cells have slender apical dendrites that terminate without a terminal tuft, usually in layer 2/3, and they display a more regular firing pattern (Kasper et al.: J Comp Neurol, this issue, 339:459–474). At embryonic day E18 (when axons of the two classes of cells are already taking different routes towards their targets) and E21, pyramidal‐like cells throughout the cortical plate all have similar soma‐dendritic morphology, with spindle‐shaped cell bodies and few, short basal dendrites but apical dendrites that all end in distinct tufts in the marginal zone. At postnatal day P3, after the axons of both cell classes have reached their targets, all pyramidal neurons in layer 5 still have distinct terminal in distinct tufts in the marginal zone. At postnatal day P3, after the axons of both cell classes have reached their targets, all pyramidal neurons in layer 5 still have distinct terminal arborizations in layer 1, though they vary in complexity and extent. The somata are now more mature (round to ovoid in shape), and the basal dendritic tree has extended. As early as P5, all cells studied could be clearly classified as tufted or untufted (considerably earlier than previously reported; Koester and O'Leary: J Neurosci 12:1382, '92), and these features correlated precisely with the projection target, as in the adult. Measurement showed that although interhemispheric cells lose their terminal tufts, in general the trunks of their apical dendrites do not withdraw but continue to grow, at roughly the same rate as those of corticotectal cells. The two classes of layer 5 pyramidal neurons differentiate from each other in three distinct phases: pathway selection by axons precedes the loss of the apical tuft by interhemispheric cells, and these morphological characteristics are established 10 days before the onset of burst‐firing in corticotectal cells. These three steps may be guided by different molecular signals. © 1994 Wiley‐Liss, Inc.
Distribution of cytochrome oxidase and parvalbumin in the primary visual cortex of the adult and neonate monkey, Callithrix jacchus
Authors: Spatz W. B. , Illing R.‐B. , Weisenhorn D. M. Vogt 
Published: January 2005

AbstractThe anatomical distributions of the mitochondrial enzyme cytochrome oxidase (CO) and of the calcium binding protein parvalbumin (PV) were studied in the striate cortex of adult and neonate New World monkeys (Callithrix jacchus). In the adult marmoset, both proteins were found in laminar arrangements similar to those described for the macaque monkey, with prominent bands of PV‐like immunoreactive (PV‐LI) puncta in layers IV and IIIb, and fairly evenly distributed PV‐LI nonpyramidal neurons. Furthermore, the pattern of CO activity in area 17 of the neonate marmoset was almost identical to the CO pattern described in neonate macaque and squirrel monkeys. It came, therefore, as a surprise to find that the adult pattern of PV‐like immunoreactivity (PV‐LI) in the marmoset striate cortex arises from a neonatal pattern strikingly different from that seen in any developmental stage of the macaque, or in any other mammal studied so far. In the deep layers IV through VI of the neonate marmoset, a large number of PV‐LI neurons was stained in bandlike patterns, their number in layers IV and V exceeding the number of PV‐LI neurons present in these layers of the adult marmoset area 17. Staining of layers IV and VI was restricted to area 17 and involved nonpyramidal cells and their exceeding the number of PV‐LI neurons present in these layers of the adult marmoset area 17. Staining of layers IV and VI was restricted to area 17 and involved nonpyramidal cells and their processes. The stained band of layer V, in contrast, continued throughout most of the neocortex. In area 17, an estimated 10 to 20% of the stained cells in layer V exhibited pyramidal shapes. The findings show that the expression of PV by visual cortical cells occurs before birth and suggest that the comparatively early onset of PV expression is not dependent on the onset of textured vision. The exuberant number of stained cells in some layers, and particularly the staining of pyramidal cells, in the neonate marmoset, suggest that a considerable number of cells possesses the stainability for PV‐LI only transiently, i.e., in the marmoset, these cells have a specific demand for parvalbumin during this phase of their development. © 1994 Wiley‐Liss, Inc.
Morphology of GABAergic neurons in the inferior colliculus of the cat
Authors: Oliver Douglas L. , Winer Jeffery A. , Beckius Gretchen E. , Marie Richard L. Saint 
Published: January 2005

AbstractThe goal of the present study was to provide a comprehensive and quantitative description of neurons immunoreactive for γ‐aminobutyric acid (GABA) in the inferior colliculus (IC) of the cat. Neurons were investigated with two different antisera and two different incubation methods. Free‐floating frozen or vibratome‐cut sections were incubated either with an antiserum to glutamic acid decarboxylase (GAD) or to GABA conjugated to protein with glutaraldehyde. Additional 1.5‐μm‐thick sections were incubated with the GABA antiserum after embedding and removal of the plastic. Quantitative data were obtained from much of this material. Despite the use of these different antisera and reaction methods, the results obtained were remarkably similar.The results show that GAD‐ or GABA‐positive neurons represent a significant population of cells in the central nucleus of the IC, up to 20% of the neurons. Most of these neurons have large or medium‐sized perikarya. In contrast, immunonegative neurons are medium‐sized or small. Many GABA‐positive neurons had proximal dendrites or somata oriented in parallel to the fibrodendritic laminae of the central nucleus and are presumed to be disc‐shaped neurons. Others have an orthogonal orientation and are presumed to be stellate cells. Large GABA‐positive neurons form two groups, those with many axosomatic endings and those with few. Collectively, these observations suggest that there are several types of GABAergic neuron in the central nucleus and, by extension, that these may participate in many types of inhibitory circuits. © Wiley‐Liss, Inc.
The ontogeny of GAP‐43 (neuromodulin) mRNA in postnatal rat brain: Evidence for a sex dimorphism
Authors: Shughrue Paul J. , Dorsa Daniel M. 
Published: January 2005

AbstractGAP‐43 is a membrane‐bound protein selectively concentrated in axonal growth cones during brain development and implicated in axonal outgrowth and elongation. A sex dimorphism in the number of synapses in certain regions of the adult rat brain has been attributed to differences in gonadal steroid hormone action during early postnatal life. The results of recent studies have demonstrated that gonadal steroids modulate GAP‐43 mRNA in regions of the postnatal and adult brain where steroid hormone receptors are concentrated. Since gonadal steroids influence the development of the sexually undifferentiated brain during the first few weeks of postnatal life, the present study investigated the ontogeny of GAP‐43 mRNA in the male and female rat brain between postnatal days 1 and 25. On postnatal days 1, 3, 6, 12, 18, and 25, brains were collected from male and female postnates and frozen, and 16 μm cryostat sections were processed and hybridized with a 35S‐labeled antisense riboprobe complementary to GAP‐43 mRNA. Evaluation of film autoradiograms demonstrated a widespread distribution of GAP‐43 mRNA in postnatal brain regions, including the cerebral cortex; bed nucleus of the stria terminalis; and medial preoptic area, ventromedial nucleus, and arcuate nucleus of the hypothalamus. Densitometric measurements revealed that GAP‐43 mRNA was transiently elevated during early postnatal life, with a subsequent decrease during brain maturation, although the pattern of change varied among the brain regions investigated. In addition, the level of GAP‐43 hybridization signal was significantly higher in the male cortex, bed nucleus, and medial preoptic nucleus, but not the ventromedial and arcuate nuclei, than in postnatal females. Analysis of slide autoradiograms demonstrated that the change in GAP‐43 mRNA during postnatal development was due to changes at the cellular level. The present results indicate that expression of GAP‐43 mRNA is transiently elevated and sexually dimorphic in certain regions of the early postnatal rat brain. The results further suggest that the differential expression of GAP‐43 in the male and female postnatal brain may be related to sex differences in neuronal outgrowth and connectivity resulting in a dimorphism in the pattern of adult neuronal circuitry. © Wiley‐Liss, Inc.
Pattern formation in the developing superior colliculus: Ontogeny of the periodic architecture in the intermediate layers
Authors: Illing R.‐B. , Graybiel A. M. 
Published: January 2005

AbstractThe superior colliculus of mammals contains a striking neurochemical architecture in which histochemically identifiable compartments are distributed in an iterative arrangement in the intermediate layers. We used stains for acetylcholinesterase activity as a compartment marker to trace ontogenesis of this architecture during pre‐ and postnatal development in the domestic cat. We found that compartmentation in the intermediate collicular layers is virtually absent at birth, and only gradually emerges during the first weeks of postnatal life. Over the same postnatal period, acetylcholinesterase activity shifts from a predominantly perikaryal expression pattern immediately postnatally to a nearly exclusive localization in the neuropil at maturity.Remarkably, a striking compartmentation of the superior colliculus was readily apparent with acetylcholinesterase histochemistry prenatally. The first appearance of a periodic architecture in the superior colliculus was observed at embryonic day 34, a time at which the collicular plate had not yet become laminated. The compartments characterized by high levels of acetylcholinesterase activity then gained in prominence until late in the prenatal period, when they receded and disappeared. The loss of the acetylcholinesterase‐positive compartments in the perinatal period did not reflect a loss of compartmentation altogether. Neonatally, there was a distinct compartmental architecture visible with enkephalin immunohistochemistry. The virtual absence of acetylcholinesterase‐positive compartments in the superior colliculus at birth therefore reflects developmental regulation of enzyme expression in the compartments, not regulation of the compartments as structural entities. We conclude that the periodic architecture, which characterizes the intermediate collicular layers in the adult cat, arises early in ontogenesis. These observations raise the possibility that the histochemical compartments are ontogenetic units that undergo remodeling as the superior colliculus matures. © Wiley‐Liss, Inc.
Direct projections from the non‐laminated divisions of the medial geniculate nucleus to the temporal polar cortex and amygdala in the cat
Authors: Shinonaga Yasuhide , Takada Masahiko , Mizuno Noboru 
Published: January 2005

AbstractThe medial geniculate nucleus (MG) is well known to send projection fibers not only to the auditory cortex, but also to the limbic structures of the forebrain including the perirhinal cortex and amygdala. In the cat, the non‐laminated portions of the MG are also known to project to the amygdala, as well as to the auditory cortical areas surrounding the primary auditory area. On the other hand, projections from the non‐laminated MG to the limbic cortical areas have not so far been studied systematically. Thus, in the present study, direct projections from the non‐laminated portions of the medial geniculate nucleus to the temporal polar cortex and amygdala were examined in the cat by retrograde and anterograde tract‐tracing techniques. The temporal polar cortex is the ventral polar region of the posterior sylvian and posterior ectosylvian gyri, which is located dorsal to the posterior rhinal sulcus and includes the ectorhinal area. After injection of cholera toxin B subunit into the temporal polar cortex, retrogradely labeled neurons were seen in the caudal two‐thirds of the medial geniculate nucleus ipsilateral to the injection; they were distributed in the non‐laminated portions of the MG (the dorsal and medial divisions and the ventromedial part of the ventral division), but not in the laminated portion (the principal part of the ventral division). These findings were confirmed by injecting Phaseolus vulgaris leucoagglutinin into each division of the MG. After the injection into each non‐laminated division, terminal labeling was observed in the temporal polar cortex. Terminal labeling was further found in the lateral amygdaloid nucleus ipsilateral to the injection. Then, cholera toxin B subunit was injected into the lateral amygdaloid nucleus; retrogradely labeled neurons were observed ipsilaterally in the non‐laminated portions of the MG, as well as in the temporal polar cortex.The results indicate that the non‐laminated portions of the MG send projection fibers to the temporal polar cortex and lateral amygdaloid nucleus, and that the non‐laminated portions of the MG and temporal polar cortex give rise to overlapping projections to the lateral amygdaloid nucleus. These connections appear to constitute neuronal links in “emotional” and/or “motivational” circuitry in the forebrain. © Wiley‐Liss, Inc.
Development of lateral line organs in the axolotl
Authors: Northcutt R. Glenn , Catania Kenneth C. , Criley Bruce B. 
Published: January 2005

AbstractLateral line sensory receptors and their cranial nerves in axolotls arise from a dorsolateral series of placodes, including the octaval placode, that gives rise to the inner ear and the octaval nerve. Anterodorsal and anteroventral placodes occur rostral to the octaval placode and give rise to anterodorsal and anteroventral lateral line nerves and electroreceptors and mechanoreceptors of the snout, cheek, and lower jaw. Middle, supratemporal, and posterior placodes occur caudal to the octaval placode and give rise to similarly named lateral line nerves, electroreceptors and mechanoreceptors of the occipital region of the head, and trunk neuromasts.All placodes, except the posterior placode, elongate, forming sensory ridges, following the genesis of sensory ganglia. Primary mechanoreceptor primordia begin to form within the central zone of the sensory ridges at stage 36; primary electroreceptor primordia originate within the lateral zones of these ridges at stage 38. The first primary mechanoreceptors erunt during stage 37; all primary mechanoreceptors have erupted at hatching (stage 41). Primary electroreceptors begin to erupt at stage 43. Secondary mechanoreceptor primordia begin to form in 1‐week‐old larvae and erupt 1–2 weeks later. Secondary electroreceptor primordia also begin to form in 1‐week‐old larvae and continue until clusters of two to five electoreceptors are formed.The developmental stages thought to characterize lateral line placodes in the earliest gnathostomes suggest that this ancestral ontogeny has been truncated in modern amphibians, and ontogenetic mechanisms underlying placodal differentiation are suggested. © Wiley‐Liss, Inc.