bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catecholamine innervation of the basal forebrain II. Amygdala, suprarhinal cortex and entorhinal cortex
Authors: Fallon James H. , Koziell David A. , Moore Robert Y. 
Published: January 2005

AbstractThe catecholamine (CA) innervation of the posterior basal forebrain, the amygdala, suprarhinal cortex and entorhinal cortex, was studied in the rat using biochemical assay and fluorescence histochemistry. The assay studies demonstrate a moderate norepinephrine (NE) content in the amygdala and entorhinal cortex with a lower value for the suprarhinal cortex. Following destruction of the locus coeruleus, the decrease in NE content of these basal forebrain structures indicates that their principal NE innervation is from locus coeruleus. An additional small NE input arises from the medullary NE neuron groups. Ablation of dopamine (DA) cell groups (substantia nigra‐ventral tegmental area, SN‐VTA) indicates that the DA input to the amygdala arises from the lateral VTA and medial half of the SN.Fluorescence histochemical studies using the glyoxylic acid‐Vibratome technique demonstrate the presence of four distinct types of CA neuron terminal plexus in the posterior basal forebrain. These include two different DA fiber types arising in SN‐VTA, small NE fibers with small varicosities arising in locus coeruleus and NE fibers with larger varicosities arising in other brainstem NE cell groups. The large NE fibers appear to enter the amygdala via the ansa peduncularis‐ventral amygdaloid bundle to innervate the central and basolateral nucleus and the anterior amygdaloid area. The locus coeruleus NE fibers appear to enter the posterior basal forebrain via both the stria terminalis and ansa peduncularis‐ventral amygdaloid bundle system to form a moderately dense innervation of the central and basolateral nuclei of the amygdala and a less dense innervation of the other areas. The DA neuron axons are concentrated in the central and basal nuclei and intercalated cell groups. Other areas receive a more diffuse DA input, with the exception of the moderately dense innervation of the suprarhinal cortex and DA “islands” in the ventral‐anterior entorhinal cortex. The DA input to the posterior basal forebrain is complex and heterogeneous and the axonal morphology differs greatly among the terminal fields within the amygdala and adjacent cortical areas.
Somatotopic organization of mechanosensory projections to SII cerebral neocortex in the raccoon (Procyon lotor)
Authors: Herron Paul 
Published: January 2005

AbstractThe pattern of projections of peripheral receptors to the neocortex in the second somesthetic receiving area (SII) was mapped in raccoons. The purpose was to determine if the projection area of peripheral receptors to the forepaw area in the SII region is disproportionally enlarged as it is in SI.Tungsten microelectrode recording procedures were used to map thoroughly the inferior wall of the suprasylvian sulcus for regions responsive to mechanical stimulation of peripheral receptors.The results show that:
The forepaw area in SII shows an enlargement commensurate with that found in the SI. This suggests that those factors that are selective for tactile acuity of the raccoon forepaw were operating in the evolution of SII as they were in SI.
The somatotopic organization of mechanoreceptive projections to SII is reversed mediolaterally compared to previous descriptions of this arrangement in other mammals: projections form axial structures lie medially and those from apical structures lie laterally along the inferior bank of the suprasylvian sulcus in the raccoon.
Organizational features of the cat and monkey cerebellar nucleocortical projection
Authors: Tolbert Daniel L. , Bantli Heinrich , Bloedel James R. 
Published: January 2005

AbstractThe organization of the cerebellar nucleocortical projection in the cat and the monkey has been studied using orthograde and retrograde neuroanatomical tracing techniques. Injections of tritiated leucine in the cat cerebellar nuclei orthogradely labeled neucleocortical fibers throughout their course to the cerebellar cortex. Their branch points in the corpus medullare, in the folial white matter, and in the granular layer were evident from the dense, continuous distribution of silver grains overlying these labeled axons. The results from the cat showed that the cerebellar nucleocortical projection is organized principally into three rostrocaudally oriented longitudinal cortical zones. Fastigial nucleocortical fibers were directed principally to the medial 1.5–2.5 mm of the ipsilateral vermis, with a lighter projection to the lateral vermis ipsilaterally and to the medial area of the vermis contralaterally. The interposed nuclei projected mainly to the paravermis‐medial hemispheric zone of the cerebellar cortex. Nucleocortical fibers from the posterior interposed nucleus projected principally to the paramedian lobule, to the medial hemispheric area of Crus I and the lobus simplex, and to the flocculus and paraflocculus. Nucleocortical projections from the anterior interposed nucleus coursed to the anterior lobe paravermis and to the ventral folia of the paramedian lobule. A lighter projection from the interposed nuclei was found to the lateral edge of the vermis and into intermediate areas of the hemisphere. Dentatocortical fibers were directed into the lateral folia of Crus I and Crus II of the lateral hemispheric zone, with a lighter projection to intermediate areas of the hemisphere of the posterior lobe and along the lateral edge of the anterior lobe hemisphere. Along the periphery of each cortical zone, the nucleocortical projection from adjacent deep nuclei overlapped slightly. The retrograde transport of horseradish peroxidase (HRP) from injection sites in the lateral hemisphere, in the medial hemisphere — paravermis, and in the vermis labeled neurons localized mainly within the dentate, interposed, and fastigial nuclei, respectively. Retrograde labeling experiments carried out in monkeys indicated that the organization of the neucleocortical projection in this species is different than that of the cat. In the primate, the nucleocortical projection to the lateral hemisphere, to the medial hemisphere — paravermis, and to the vermis appeared to arise principally from the dentate nucleus. There was a secondary input to the paravermis and vermis arising from the interposed and fastigial nuclei, respectively. This evidence suggests that the cerebellar nucleocortical system undergoes a significant phylogenetic change in its organization between the cat and primate. These organizational differences are discussed in light of possible functional implicatons.
Genetic control of retinal ganglion cell projections
Authors: Lavail Jennifer H. , Nixon Ralph A. , Sidman Richard L. 
Published: January 2005

AbstractWe have assessed the effects of 15 pigmentation mutations on the development of retinal ganglion cell projections in mice in two ways: (1) by analyzing the pattern of innervation of the ipsilateral lateral geniculate nucleus as mapped in autoradiograms of brains of animals killed 12 days after intravitreal injection of 3H‐proline into one eye and (2) by determining the ratio of axonally transported radioactive protein in the contralateral and ipsilateral optic tracts after similar intravitreal injections. Analysis of the ratio of transported protein in the two optic tracts provides a new and useful assay of the degree of decussation in experimental animals. The effects of the mutations on eye pigmentation, whole eye melanin content and relative tyrosinase activity also were examined. The degree of ipsilateral innervation generally correlates with the degree of pigmentation of the retinal pigment epithelium and with tyrosinase activity. However, discrepancies have been found in ch and ce mutants. In these animals the pigment epithelium is well pigmented, and the area of ipsilateral innervation in the lateral geniculate nucleus is extensive, despite a high ratio of label in contralateral to ipsilateral optic tracts and low tyrosinase activity. Furthermore, mice heterozygous for the c2J allele have pigmentation and optic projections that are normal even though tyrosinase is reduced to 40% of normal. The few anomalous results suggest that alternative or additional factors may control optic axon projections.
Proliferative and degenerative events in the early development of chick dorsal root ganglia. II. Responses to altered peripheral fields
Authors: McMillan Carr Virginia , Simpson Sidney B. 
Published: January 2005

AbstractResponses of chick embryo dorsal root ganglia to early wing bud amputation were examined histologically using tritiated thymidine (3H‐TdR) and autoradiography to analyze proliferation and the Feulgen procedure to visualize degenerating cells. Right wing buds were amputated at stage 15 or 16. At 4.5 to 9.5 days of incubation embryos were given a 1‐hour exposure to 3H‐TdR and fixed. Feulgen‐stained autoradiographs were examined for percentage of cells labelled (labelling index) or degenerating (degeneration index) in lateroventral (LV) and mediodorsal (MD) regions of brachial (G14‐16) and nonbrachial (G12, 13, 17) ganglia. The earliest response to amputation was a highly significant increase in degeneration indices of LV and MD regions of ipsilateral brachial ganglia at 5.5 days. Significant brachial LV responses were observed throughout the remainder of the experimental period. Two peaks occur in this response: at 5.5 days, corresponding to the peak seen in normal nonbrachial ganglia, and at 8.5 days, having no counterpart in normal development. In brachial MD regions significant degenrerative responses occur at most times examined. Significant responses also occur at 7.5 and 8.5 days in MD regions of nonbrachial ganglia. The presence of MD responses in our material indicates that maturation of at least some MD neurons occurs earlier than previously thought.Significant labelling responses occur in brachial LV regions from 7.5 days on. Because other studies (Carr and Simpson, '78a) show that time is after the end of large‐scale neuronal production, this labelling response must be nonneuronal in nature. We conclude that this labelling is a secondary response to amputation, consequent to the greatly increased cellular degeneration.Results of experiments involving addition of limb buds at the brachial level are also presented.
A regional specialization in the opossum's retina: Quantitative analysis of the ganglion cell layer
Authors: Hokoç Jan Nora , Oswaldo‐Cruz Eduardo 
Published: January 2005

AbstractThe distribution of ganglion cells in the opossum's retina was determined from flat‐mounted preparations stained with cresyl‐violet.The retinal area is 109 mm2 (SD = 16 mm2). Maps of ganglion cell density were made from retinae of seven animals. in all maps iso‐density lines were approximately concentric, showing a slight elongation towards the nasal region. Cell density varied from 400 cells/mm2 at the extreme periphery to 2,900 cells/mm2 in the region of highest count, the are centralis. The center of this region lies 1.85 mm (26.3°) temporal to the center of the optic nerve head. The average total number of ganglion cells is 77,384 (SD = 10,173).Based upon soma diameter histograms ganglion cells were classified into three groups, showing at area centralis peaks at 7 μm, 12 μm and 15 μm respectively. Cell soma diameter ranged from 6 μm to 21 μm, larger values being observed at the periphery.
Electron microscopic studies on the lamprey meninges
Authors: Nakao Taisuke 
Published: January 2005

AbstractLamprey meninges were revealed to consist of four layers. The I (outermost) layer was made up of densely packed collagen fibrils and microfibrils with fibrocytes interposed between them. It contained a vascular network (epidural vascular plexus). The II layer was a cellular layer, consisting of two parts: the outer, membranous and the inner, spongy part. The membranous part was composed of two sheets of type 1 cells which were held together by desmosomes, gap junctions and tight junctions. Continuous basal laminae were found on both the outer and the inner surface of the membranous part. The spongy part consisted of type 2 cells, collagen fibrils and microfibrils, which were loosely arranged. Type 2 cells were joined together with each other, or with type 1 cells, by gap junctions. These cells lacked a basal lamina covering. The III layer was a peculiar thick layer, being mostly occupied by fine filamentous matrix substance with scattered round cells, fibroblasts and microfibrils. The IV (innermost) layer was a thick fibrous one, consisting of two parts: the outer, vascular and the inner, loose part. The former consisted of a vascular network (perineural vascular plexus) and thick bundles of microfibrils which frequently contained a dense filamentous core. The latter was composed of loosely arranged collagen fibrils.The inner part of the I layer (inside the epidural vascular plexus) was considered to correspond to the true dura, and the II and IV layer to the arachnoid and pia in the meninges of higher animals, respectively. Characteristically the subarachnoid space was absent in lamprey meninges, and instead a peculiar “gelatinous” layer, III layer, was present between the II and IV layer.
Patterns of cell proliferation in the developing retina of the clawed frog in relation to blood supply and position of the choroidal fissure
Authors: Beach D. H. , Jacobson Marcus 
Published: January 2005

AbstractThe pattern of retinal vasculative is described and the position at which cell proliferation at the ventral retinal margin is maximal was shown to be at the point of entry of the ventral blood vessels. To test whether there is a causal relation between retinal blood supply and retinal cell production, surgical inversion of the eye, transplantations and excisions of retina were done to change the pattern of retinal vasculature. The growth pattern of inverted eyes was normal with respect to the internal axes of the eyes. After excision of part of the retina or after fusion of retinal fragments to form compound eyes, the pattern of retinal cell proliferation was not correlated with the distribution of retinal blood vessels, but was correlated with the position(s) of the choroidal fissure(s).
Substrate pathways which guide growing axons in Xenopus embryos
Authors: Katz Michael J. , Lasek Raymond J. 
Published: January 2005

AbstractOptic axons from eyes transplanted to hindbrain and spinal cord (i.e., non‐optic areas) in Xenopus embryos reproducibly follow a particular pair of continous tracts, the external sensory tract and the internal sensory tract. The course of the external sensory tract may coincide with the course of the general somatic afferent tracts (i.e., the ascending and descending tracts of nerve V, the tract of Lissauer, and the Rohon‐Beard cell tracts). The course of the internal sensory tract parallels that of the external sensory tract but runs more medially. Transplanted optic axons follow the same tracts regardless of where along the neural axis the axons have entered the CNS. What kind of developmental cues guide these optic axons? It is unlikely that the guidance cues are organized as spatial coordinates, rather it appears that the optic axons of these two tracts are guided along pre‐existing substrate routes. We have called these routes substrate pathways. Substrate pathways may be a device normally used for organizing fiber tracts in the developing nervous system.
Differential projections of cortical sensorimotor areas upon the dorsal column nuclei of cats
Authors: Weisberg Julie A. , Rustioni Aldo 
Published: January 2005

AbstractCortical projections to the dorsal column nuclei (DCN) of cats arise from layer V pyramids throughout the sensorimotor cortex and also from the second somatosensory cortical area (SII). In this study, the relative contribution from various cortical areas to different portions within the DCN‐complex has been investigated in cats with restricted cortical lesions and using the Fink‐Heimer technique.The sensorimotor cortex (areas 4, 3, 1, and 2) projects throughout most of the rostro‐caudal extent of the gracile nucleus. Densest projections arise from the upper bank of the cruciate sulcus containing mainly the hindlimb region (area 4), from the medial wall of the posterior sigmoid gyrus (mainly area 3a) and terminate in the rostral as well as in the clusters regions of the gracile nucleus. The contribution of cortico‐gracile projections from the hindlimb regions of areas 3b, 1 and 2 are much less conspicuous and terminate mainly in the rostral region of the nucleus. The nucleus z, the medullary relay for Ia fibers from the hindlimb, receives exceedingly sparse cortical projections. Dense projections to the cuneate n. arise from the cortical forelimb representation in the posterior sigmoid gyrus (areas 3a and 4) and laterally in the upper bank of the cruciate sulcus (area 4). The distribution pattern of cortical projections within the cuneate nucleus is however different from that within the gracile n. since (a) none of the lesioned cortical areas in the forelimb representation project to the clusters region, and (b) cortical projections terminate most densely in the base of the cuneate n., a medullary relay for Ia fibers from the forelimb. Sparse projections to the rostral region of the cuneate n. arise uniformly from all cytoarchitectonic areas of the forelimb representation. Cortical projections from SII are sparse and confined to the base and rostral region of the cuneate n.The results provide further evidence for the origin of descending projections upon the DCN mainly from cortical regions related to movement control. Further, it is suggested that cortico‐DCN control is biased toward nuclear subdivisions related to cutaneous afferents from the hindlimb within the gracile n.‐nucleus Z complex but toward nuclear subdivisions related to deep and muscle afferents from the forelimb within the cuneate nucleus.
Restoration of visual cortical plasticity by local microperfusion of norepinephrine
Authors: Kasamatsu Takuji , Pettigrew John D. , Ary Marylouise 
Published: January 2005

AbstractUsing a newly developed technique of continuous microperfusion, we obtained further evidence in support of our hypothesis that the neocortical catecholamines (CAs), particularly norepinephrine (NE), are responsible for a high level of cortical plasticity. We used the visual cortical changes in ocular dominance which follow a brief monocular deprivation as a simple and reliable index of cortical plasticity. Local perfusion of kitten visual cortex with 1 mg/ml (4.0 mM) 6‐hydroxydopamine (6‐OHDA) prevented the effects of monocular deprivation in kittens, thus replicating the results we had obtained using intraventricular injections (Kasamatsu and Pettigrew, '76b, '79). Locally perfused NE at a concentration of 10−2 mg/ml (48.6 μM) restored visual cortical plasticity in animals which were no longer susceptible to brief monocular lid‐suture. These numbers refer to the concentration of solutions in the cannula/minipump system. The effective concentrations at the site of recording (about 2 mm away) are probably much lower than these. This effect of NE perfusion was seen both in kittens which had received prior 6‐OHDA treatment as well as in older animals which had outgrown the susceptible period. In the kittens we obtained a nearly complete shift in ocular dominance toward the open eye and in the older animals a decrease in binocularity was obtained. The changes were found only in the local region of visual cortex perfused with either NE or 6‐OHDA, while nearby cortical regions in the same animals were unaffected. There were no obvious changes in receptive field properties of individual neurons other than ocularity, and externally perfused NE did not itself reduce binocularity in normal animals: the effects of NE described above only occurred when the animal's visual experience was simultaneously altered. These results support the view that NE plays an important role in cortical plasticity.
Connections of areas 3b and 1 of the parietal somatosensory strip with the ventroposterior nucleus in the owl monkey (Aotus trivirgatus)
Authors: Lin Chia‐Sheng , Merzenich Michael M. , Sur Mriganka , Kaas Jon H. 
Published: January 2005

AbstractAnatomical tracers were injected into electrophysiologically defined sites in somatosensory cortical Area 3b (SI proper) and Area I (posterior cutaneous field) of owl monkeys after these cortical subdivisions had been extensively explored in microelectrode mapping experiments. These mapping experiments revealed that both Areas 3b and 1 contain complete and separate representations of the body surface (Merzenich et al., '78). Restricted injections of the retrograde tracer, horseradish peroxidase (HRP), into either Area 3b or Area 1 labeled neurons within a band of cells in the ventroposterior nucleus (VP). The location of the labeled band in VP varied with the location of the injection site in both representations, and the labeled region of VP was overlapping for injections in corresponding body parts in the two representations. Neurons projecting to the hand and foot cortical representations were in architectonically identified subnuclei. Because injections into either Area 3b or Area 1 labeled over half of the neurons in the appropriate regions of VP, it appears that some neurons in VP project to both cortical representations. Finally, injections of HRP combined with the anterograde tracer, 3H‐proline, indicate that VP neurons are reciprocally interconnected with both Areas 3b and 1.
Somatostatin neurons and their projections in dog diencephalon
Authors: Hoffman Gloria E. , Hayes Terry A. 
Published: January 2005

AbstractImmunocytochemical localization of the tetradecapeptide somatostain was performed in dog brain using the unlabeled antibody enzyme method. A large population of immunoreactive neurons was seen in the periventricular areas of the preoptic area and anterior hypothalamus. This field of neurons extended into the paraventricular nucleus, arcuate nucleus and tuberal areas surrounding the ventromedial nuclei. Fibers from the periventricular somatostatin cells projected into the median eminence, the third ventricle, the pars nervosa of the hypophysis, the organum vasculosum of the lamina terminalis, the medial preoptic area and the interstitial nucleus of the stria terminalis. The tuberal cells projected to the ventromedial nucleus and the cells of the arcuate nucleus terminated within the arcuate nucleus as well as within the contact zone of the median eminence. These findings suggest that somatostatin can exert hormonal effects via the vasculature or the cerebrospinal fluid, or transmitter and/or neuromodulatory effects via contacts with other neurons.
Sulfide silver stainability of a type of bouton in spinal cord motoneuron neuropil: An electron microscopic study with Timm's method for demonstration of heavy metals
Authors: Daa Schrøder Henrik 
Published: January 2005

AbstractSpinal cord motoneuron neuropil (cervical and lumbar enlargements) has been studied at the ultrastructural level after fixation with glutaraldehyde and staining with uranyl acetate and lead citrate. Based on the appearance of the synaptic specializations, different types of boutons were identified and correlated with the classification of bouton types based on osmicated tissue.The sulfide silver method for histochemical demonstration of heavy metals was applied to the same region. The localization of reaction products (silver grains) was predominantly in the terminals. Within the bouton, the grains were mainly in the specialized region of the synaptic contact, and the presynaptic network has also labelled, but to a lesser degree. All stained boutons had the same type of paramembranous synaptic specialization, but not all of the boutons with this type of specialization were stained. The stained boutons are interpreted as a fraction of the ‘F’ boutons.