bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tonotopic organization, architectonic fields, and connections of auditory cortex in macaque monkeys
Authors: Morel A. , Garraghty P. E. , Kaas J. H. 
Published: January 2005

AbstractMicroelectrode recordings were used to investigate the tonotopic organization of auditory cortex of macaque monkeys and guide the placement of injections of wheat germ agglutininhorse radish peroxidase (WGA‐HRP) and fluorescent dyes. Anatomical and physiological results were later related to histological distinctions in the same brains after sections were processed for cytoarchitecture, myeloarchitecture, acetylcholinesterase (AchE), or cytochrome oxidase (CO). The experiments produced serveral major findings. (1) Neurons throughout a broad expanse of cortex were highly responsive to pure tones, and best frequencies could be determined for neurons in arrays of recording sites. (2) The microelectrode recordings revealed two systematic representations of tone frequencies, the primary area (AI) and a primary‐like rostral field (R) as previously described. The representation of high to low frequency tones in A1 was largely caudorostral along the plane of the sulcus. A reversal of the order of representation of frequencies occurred in R. (3) AI and R together were coextensive with a koniocellular, densely myelinated zone that expressed high levels of AchE and CO. These architectonic features were somewhat less pronounced in R than AI, but a clear border between the two areas was not apparent. (4) Cortex bordering AI and R was less responsive to tones, but when best frequencies for neurons could be determined, they matched those for adjoining parts of AI and R. (5) Architectonically distinct regions were apparent within some of the cortex bordering AI and R. (6) The major ipsilateral cortical connections of AI were with R and cortex immediately lateral and medial to AI. (7) Callosal connections of AI were predominately with matched locations in the opposite AI, but they also included adjoining fields. (8) Neurons in the ventral (MGV), medial (MGM), and dorsal (MGD) nuclei of the medial geniculate complex projected to AI and cortex lateral to AI. (9) Injections in cortex responsive to high frequency tones labeled more dorsal parts of MGV than injections in cortex responsive to low frequency tones. © 1993 Wiley‐Liss, Inc.
Connections of the olfactory bulb in the gymnotiform fish, Apteronotus leptorhynchus
Authors: Sas Emilia , Maler Leonard , Weld Madeline 
Published: January 2005

AbstractThis work examines the connectivity of the olfactory bulb in the gymnotiform fish Apteronotus leptorhynchus. Wheat germ agglutinin conjugated horseradish peroxidase was iontophoresed in different areas and depths of the bulb in order to define its efferent and afferent connections. The olfactory bulb projects bilaterally via the medial (medial and centromedial fascicles) and lateral olfactory (lateral and centrolateral fascicles) tracts. The nervus terminalis courses through the ventromedial aspect of the bulb to terminate in parts of the medial subpallium and hypothalamus. Its telencephalic component could be identified by a nonpreadsorbable substance P‐like immunoreactivity. Fibers within the medial olfactory tract form four telencephalic terminal fields: peduncular, medial, intermediate and posterior fields. The diencephalic terminal fields in the habenula, preoptic, and hypothalamic areas appear to correspond to some of the nervus terminalis fibers (von Bartheld and Meyer [1986] Cell Tissue Res. 245: 143‐158, Krishna et al. [1992] Gen. Comp. Endocrinol. 85:111‐117), and to axons of telencephalic bulbopetal cells of area dorsalis posterior. The terminal fields of the medial olfactory tract and nervus terminalis partially overlap in the ventral telencephalic areas partes ventralis, supracommissuralis, and rostral preoptic region. The lateral olfactory tract forms a lateral terminal field and contributes to the intermediate and posterior terminal fields. Olfactory fibers cross in the interbulbar, anterior, and habenular commissures and tuberal decussation. Consistent differnces were noted between the medial and lateral olfactory bulb, with respect to their cytoarchitectonics, immunohistochemistry, and connections. In addition to the olfactory nerve, bulbar afferents are predominantly ipsilateral, with minor inputs originating from the contralateral bulb and telencephalic area dorsalis posterior, nucleus raphe centralis, and locus ceruleus. © 1993 Wiley‐Liss, Inc.
Galanin immunoreactivity within the primate basal forebrain: Evolutionary change between monkeys and apes
Authors: Benzing William C. , Kordower Jeffrey H. , Mufson Elliott J. 
Published: January 2005

AbstractGalanin immunoreactivity (GAL‐ir) is differentially expressed within the basal forebrain of monkeys and humans. Most monkey magnocellular basal forebrain neurons colocalize GAL‐ir. In contrast, virtually no human magnocellular basal forebrain neurons express GAL‐ir. Rather, an extrinsic galaninergic fiber plexus innervates these neurons in humans. The present study examined the expression of GAL‐ir within the basal forebrain of apes to establish the phylogenetic level at which this transformation occurs. The staining patterns of GAL‐ir within the basal forebrain of both lesser (gibbons) and great (chimpanzee and gorilla) apes were compared to that previously observed within monkeys and humans. All apes displayed a pattern of basal forebrain GAL‐ir indistinguishable from humans. GAL‐ir was not expressed within ape basal forebrain magnocellular neurons as seen in monkeys. Rather like humans, a dense collection of GAL‐ir fibers was seen in close apposition to magnocellular perikarya. In addition, a few GAL‐ir parvicellular neurons were scattered within the ape basal forebrain. These data indicate that the evolutionary change in the expression of GAL‐ir within the primate basal forebrain occurs at the branch point of monkeys and apes. © 1993 Wiley‐Liss, Inc.
Quantitative analyses of intracellularly characterized and labeled thalamocortical projection neurons in the ventrobasal complex of primates
Authors: Havton L. A. , Ohara P. T. 
Published: January 2005

AbstractThis study describes the architecture of neurons and individual dendritic arbors of thirteen intracellularly labeled thalamocortical projection neurons that respond to non‐noxious stimuli from the primate (Macaca fascicularis or Macaca mulatta) ventrobasal complex (VB). The neurons compose a homogeneous morphological class with total dendritic lengths from 10,169 μm to 21,711 μm (mean 17,615 μm ± 3,705). The labeled neurons were remarkably similar in most measured parameters including the number of dendrites (7.5 ± 1.2), percentage of dichotomous branching (89.8% ± 3.4), and contribution of terminal branches to total dendritic length (88.4% ± 2.0).The individual dendrites ranged in total length from 443 μm to 7,657 μm with a mean of 2,346 μm (±137, n = 98). There was a positive correlation between stem dendrite diameter and total dendrite length, making it possible to estimate the total size of an individual dendrite by measuring the stem dendrite diameter. There was only a small increase in mean path distance with increasing dendritic size at the whole neuron and individual dendritic levels, so that for individual dendrites the mean path distance of a dendrite consisting of only two segments was 199 μ, while the mean path distance for a dendrite with eight segments was only 45 μm longer. Analysis of dendrite diameter, segment order, and path distance shows that dendritic diameter is not reliable for determining the location of synaptic contacts viewed by electron microscopy onto dendritic trees. The small variation of measured parameters between these neurons presents a powerful tool for future developmental, plasticity and comparative studies of VB neurons. © 1993 Wiley‐Liss, Inc.
Subpopulations of GABA neurons containing somatostatin, neuropeptide Y, and parvalbumin in the dorsomedial cortex of the lizard Psammodromus algirus
Authors: Dávila Josée Carlos , Megías Manuel , de la Calle Adelaida , Guirado Salvador 
Published: January 2005

AbstractDifferent subpopulations of GABA neurons containing the neuropeptides somatostatin and neuropeptide Y, and the calcium binding protein parvalbumin were studied by immunocytochemistry using light and electron microscopy in the dorsomedial cortex of the lizard Psammodromus algirus to investigate the connectivity of different subsets of GABA neurons in the lizard dorsomedial cortical circuitry and to compare cortical regions of reptiles and mammals. GABA neurons were classified into different subsets by using the peroxidase anti‐peroxidase immunohistochemical method on adjacent Araldite‐embedded semithin sections. GABA neurons in the dorsomedial cortex fall into three major subsets: (1) neurons with somatostatin (and neuropeptide Y), which accounted for about 44% of the GABA population; (2) neurons with parvalbumin, which accounted for about 13% of the GABA neurons; and (3) neurons without parvalbumin or neuropeptides, which represented 40% of all GABA cells. This division of GABA neurons in non‐overlapping subpopulations of neuropeptide‐ and parvalbumin‐containing cells is similar to that found in the mammalian hippocampal formation. On the basis of the nerve terminal fields, somatostatin‐ and parvalbumin‐immunoreactive neuronal populations appear to be functionally different, acting on different portions of the projection neurons. Parvalbumin‐immunoreactive neurons inhibit the pyramidal neurons at the cell body level, whereas somatostatin‐immunoreactive neurons inhibit them on distal dendrites. The results of the present study add more similarities between the lizard dorsomedial cortex and parts of the mammalian hippocampus. © 1993 Wiley‐Liss, Inc.
The inhibitory motoneurons of crayfish thoracic limbs: Identification, structures, and homology with insect common inhibitors
Authors: Wiens T. J. , Wolf H. 
Published: January 2005

AbstractThe three inhibitory motoneurons supplying crayfish thoracic limbs were identified, stained, and compared structurally. The inhibitors to the walking leg muscles (in Orconectes) were identified anatomically by a combination of immunocytochemical staining for gammaaminobutyric acid (GABA) or glutamate decarboxylase and differential backfill staining with nickel and cobalt ions. The cheliped inhibitors were identified intracellularly and injected with Lucifer Yellow (Pucifustucus) or cobalt (Procumbarus). The common inhibitor (CI) in each thoracic segment has a medial or slightly contralateral soma near the ganglion's posterior boundary, a gently curving primary neurite, an extensive ipsilateral dendritic tree, and an axon emerging through the anterior root. The stretcher‐closer inhibitor (SI) has a soma slightly anterior and ipsilateral to the CI's, a sharply bent proximal neurite, a smaller dendritic tree, and an axon in the posterior root. The opener inhibitor (OI) lies more laterally and often posterior to the CI; its diagonally directed neurite enters the posterior root. The inhibitors' structures were related to major neuroanatomical landmarks within the ganglion, to soma positions of excitatory motoneurons revealed by backfilling, and to soma locations of inhibitory interneurons revealed by GABA‐like immunoreactivity.In their peripheral distributions to the leg muscles and in their central structures, these crayfish limb inhibitors show striking similarities with those of the locust. Crayfish and locust thoracic ganglia also show more general neuroanatomical similarities. These observations suggest that the crayfish CI, SI, and 01 are, respectively, homologous with the locust CI1 CI2, and CI3. The implications of such a homology for arthropod phylogeny are discussed. © 1993 Wiley‐Liss, Inc.
Glutamatergic and cholinergic projections to the pontine inhibitory area identified with horseradish peroxidase retrograde transport and immunohistochemistry
Authors: Lai Y. Y. , Clements J. R. , Siegel J. M. 
Published: January 2005

AbstractPrevious studies in our laboratory have shown that microinjection of acetylcholine and non‐N‐methyl‐D‐aspartate (NMDA) glutamate agonists into the pontine inhibitory area (PIA) induce muscle atonia. The present experiment was designed to identify the PIA afferents that could be responsible for these effects, by use of retrograde transport of wheat germ agglutinin conjugated horseradish peroxidase (WGA‐HRP), glutamate immunohistochemistry and NADPH‐diaphorase staining techniques. Experiments were performed in both decerebrate and intact cats. Dense retrograde WGA‐HRP labelling was found in neurons in the periaqueductal gray (PAG) and mesencephalic reticular formation (MRF) at the red nucleus (RN) level, ventral portion of paralemniscal tegmental field (VFTP), retrorubral nucleus (RRN), contralateral side of PIA (CPIA), pontis reticularis centralis caudalis (PoC), and most rostral portion of the nucleus parvicellularis (NPV) and nucleus praepositus hypoglossi (PH) at the level of the pontomedullary junction; moderate labelling was seen in pedunculopontine nucleus, pars compacta (PPNc), laterodorsal tegmental nucleus (LDT), superior colliculus (SC), MRF and PAG at the level caudal to RN, medial and superior vestibular nuclei, and principle sensory trigeminal nucleus (5P); and light labelling was seen in dorsal raphe (DR) and locus coeruleus complex (LCC). The projection neurons were predominantly ipsilateral to the injection site, except for both vFTP and RRN, which had more projection cells on the contralateral side. Double labelled WGA‐HRP/NADPH‐d neurons could be found in PPNc and LDT. Double labelled WGA‐HRP/glutamatergic neurons could be seen at high densities in MRF, RRN, vFTP, and cPIA, moderate densities in SC, LDT, PPNc, PoC, and NPV, and low densities in PH, 5P, DR, LCC, and PAG. No cells in LDT and PPNc were triple labelled with NADPH‐d, glutamate antibody and WGA‐HRP. The mesopontine efferents identified here may mediate the suppression of muscle tone in REM sleep and coordinate muscle tone during head and neck movements. © 1993 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
Differential action of the albino mutation on two components of the rat's uncrossed retinofugal pathway
Authors: Chan S. O. , Baker Gary E. , Guillery R. W. 
Published: January 2005

AbstractThe development of the uncrossed retinofugal pathways in normally pigmented and albinorats, aged from embryonic day (E) 14.5 to E18.5, was investigated. Dil was placed into one optic tract and the retinal origin of the uncrossed component, as well as its course in the optic stalk, was studied. The results show that, as in the mouse, the uncrossed retinal projection has two components. The first component is seen at E15.5 in normally pigmented animals. It develops exclusively in the central parts of the retina and is normal in albino littermates. The second component, which arises from the peripheral parts of the ventrotemporal retina, is seen two days later at E17.5 in all animals but is significantly smaller in albinos than in their pigmented littermates.Studies of axons in the optic stalk labelled retrogradely with DiI placed in the optic tract indicate that the uncrossed axons have no preference for any position in the stalk except when they approach the chiasm, where they tend to accumulate at the caudal region of the stalk. The uncrossed axons intermingle with the crossed axons along the entire length of the stalk. In albino embryos, no obvious difference in the prechiasmatic course of uncrossed axons was seen at any age examined.It is concluded that the albino mutation in rats affects the late ventrotemporal component of the uncrossed pathway selectively. It does not act on the early central component. Further, the intermingling of crossed and uncrossed axons in the stalk and the apparently unaffected prechiasmatic course of uncrossed axons in albinos indicate that the albino gene has its primary action in the retina. © 1993 Wiley‐Liss, Inc.
Light and electron microscopic immunocytochemical localization of PKCδ immunoreactivity in the rat central nervous system
Authors: Merchenthaler István , Liposits Zsolt , Reid Joanne J. , Wetsel William C. 
Published: January 2005

AbstractProtein kinase C (PKC) is one of the major cellular signal transduction systems. Since at least nine different PKC isoenzymes have been described, the purpose of the present studies was to identify the regional, cellular, and subcellular distributions of PKCδ in the rat central nervous system (CNS) by light and electron microscopic immunocytochemistry. We have found that PKCδ immunoreactivity is present in all major subdivisions of the rat CNS. Within each of the subdivisions, PKCδ immunoreactivity is localized to perikarya that monitor sensory and motor functions. More specifically, PKCδ is found in the olfactory bulb, cerebral cortex, lateral septum, thalamus, vestibular and cochlear nuclei, inferior olive, nucleus of the solitary tract, cerebellum, and superficial layers of the dorsal horn in the spinal cord. In most cases, the distribution of this isoenzyme is distinct from that of the conventional isoforms. Within the CNS, PKCδ is localized primarily in neurons; however, neurons of the same type are not uniformly labeled. This is most evident in the cerebellum, where alternating columns of Purkinje cells are immunostained. While PKCδ is prominent in perikarya, occasional immunostaining is seen in dendrites, fibers or axons, and nerve terminals. Electron microscopic analysis of the posterolateral nucleus of the thalamus reveals that the cell nucleus, the rough endoplasmic reticulum, and the plasma membrane are all immunopositive. Since each of the PKC subspecies may have different substrate, lipid, and other co‐factor requirements, the regional, cellular, and subcellular distribution of each of these isoforms should help to define their functional environments. © 1993 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
Branching projections from mesopontine nuclei to the nucleus reticularis and related thalamic nuclei: A double labelling study in the rat
Authors: Spreafico R. , Amadeo A. , Angoscini P. , Panzica F. , Battaglia G. 
Published: January 2005

AbstractBranching projections from pedunculopontine and laterodorsal tegmental nuclei to different thalamic targets were studied by means of a double retrograde tracing technique. The results show a topographic distribution of mesopontine neurons projecting to different thalamic targets. In addition, the present data demonstrate that a small percentage (≤ 5%) of mesopontine neurons projecting to the intralaminar nuclei or to the rostral pole of the reticular nucleus innervate both these areas by means of branching axons. By contrast, a large number of mesopontine neurons projecting to the sensorimotor thalamic nuclei send axon collaterals to the caudal part of the reticular nucleus. The present findings support the hypothesis of an inhomogeneity of different sectors of the thalamic reticular nucleus. Thus, this nucleus can be differentiated into two functional areas, in accordance with their connections with functionally different cortical fields and thalamic districts. The possibility that these two areas of the thalamic reticular nucleus subserve different mechanisms during sleep phenomena is discussed. © 1993 Wiley‐Liss, Inc.
Transient neovascularisation of the frog retina during optic nerve regeneration
Authors: Tennant M. , Moore S. R. , Beazley L. D. 
Published: January 2005

AbstractIn conditions such as diabetic retinopathy, degenerative events in the retina are associated with neovascularisation. It is well established that a proportion of retinal ganglion cells die during optic nerve regeneration in the frog. The present study has determined whether neovascularisation takes place during this regenerative process.To do so, the pattern of blood vessels overlying the retinal ganglion cell layer was analysed in the frog Litoria (Hyla) moorei. We examined normal animals and those undergoing optic nerve regeneration following nerve crush. Blood vessels were visualised by perfusion with Indian ink and retinae were prepared as wholemounts.In normal animals, the vascular tree was found to lie superficial to the nerve fibre layer and was more complex in regions overlying the area centralis and visual streak. After nerve crush, abnormal blood vessels transiently formed between the existing branches of the vascular tree. The new vessels were concentrated as an annulus centred on the optic nerve head and over the area centralis in midtemporal retina. The neovascularisation became most extensive between 6 and 10 weeks postcrush and disappeared by 12 weeks. The spatiotemporal sequence of neovascularisation suggests that it is triggered by accumulations of degenerating material formed as a proportion ofthe ganglion cells die during optic nerve regeneration. © 1993 Wiley‐Liss, Inc.
Optic nerve degeneration induces the expression of MHC antigens in the rat visual system
Authors: Rao Kanchan , Lund Raymond D. 
Published: January 2005

AbstractThe brain has long been considered to be an immunologically privileged site. However, privilege is not absolute, as has been shown by the inability of foreign tissue grafts to survive indefinitely in the brain. The rejection of this tissue is accompanied by the upregulation of major histocompatibility complex (MHC) antigen expression. Therefore it is essential to define conditions that influence the expression of these antigens in the brain, especially since such a definition may further the understanding of disease processes that lead to the autoimmune destruction of the central nervous system. Here we show that both MHC class l and class II antigens are expressed within 1 or 2 days of eye removal by cells showing the morphological characteristics of microglia. Expression is seen along the optic pathway and within the brainstem centers to which optic axons project. In the early stages of the reaction, MHC class I antigen expression is seen throughout the optic pathway, including the terminal distribution areas of the subcortical visual centers, while MHC cells class II are localised mainly to degenerating myelinated fiber systems. These changes are not accompanied by any alteration in the integrity ofthe blood‐brain barrier. During the second week postlesion, class l positive cells are found beyond the confines of the degenerating pathways, while class II positive cells are seen within regions such as the stratum griseum superficiale of the superior colliculus, where few myelinated axons are present. There is subsequent diminution of MHC positive cells, but a small number of cells are still seen 60 days post‐lesion.Focal lesions within the eye show that at early survival times, while class l MHC positive cells are distributed throughout the nerve, class II positive cells are largely absent from the unmyelinated segment of the nerve. Retrograde changes in the retina after nerve section are accompanied only by MHC class l antigen expression. These observations show that neural degeneration is accompanied by a rigid sequence of events involving expression of MHC antigens by microglia. If foreign antigens were present in the brain while these events were taking place, it is possible that such antigens would be recognised and destroyed by the host immune system. © 1993 Wiley‐Liss, Inc.