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At least 19 recordsLinked to original sources
PubMed1978

Anatomical mapping of retino-tectal connections in developing and metamorphosed Xenopus: evidence for changing connections.

Neural connections between the eye and optic tectum in Xenopus laevis were anatomically traced by observing the tectal location of Wallerian degeneration after discrete retinal lesion. These retinotectal connections were mapped in postmetamorphic frogs and tadpoles at stage 51, the stage at which retinal axons have grown into about the rostral one-half of the tectum. The course of the experimental degeneration was the same in frogs and tadpoles, but degeneration proceeded faster in the younger animals. In the frogs, connections were ordered, with nasal retina mapping to the caudal part of the tectum and temporal retina mapping to the rostral tectum. In the tadpoles, within the innervated area at the rostral tectum, the retino-tectal connections were generally organized as in the adults, with the temporal retina mapping to the rostral part of the innervated tectum and nasal retina mapping primarily to the caudal part. But a portion of the nasal fibers consistently mapped to the far rostral tectum as well. Electron microscopic observations showed degenerating synaptic terminals at both rostral and caudal portions of the innervated tectum after lesion of just the nasal retina. Degeneration was not seen in control animals. These results indicate that some fibers (particularly from nasal retina) may shift their terminals caudally on the tectum to match tectal growth and produce the adult pattern of connections. If there is such connection readjustment, the 'aberrant' connections from nasal retina in tadpoles may be an indication of this process.

Animals↗
PubMed1978

Pattern separability and the effect of the number of connections in a random neural net with inhibitory connections.

It has been claimed that pattern separation in cerebellar cortex plays an important role in controlling movements and balance for vertebrates. A number of the neural models for cerebellar cortex have been proposed and their pattern separability has been analyzed. These results, however, only explain a part of pattern separability in random neural nets. The present paper is intended to study an extended theory of pattern separability in a new model with inhibitory connections. In addition to this, the effect of the number of connections on pattern separability is cleared up. It is also shown that the signal from the inhibitory connections has crucial importance for pattern separability.

Action Potentials↗
PubMed1978

[Nuclei of the mammillary bodies and their fiber connections in cattle (Bos taurus var. domesticus). 2. Fiber connections of the mammillary bodies in cattle].

1. In the present information the course of fibre pathways which are connected with the mammillary body of the cattle is described in 14 series of brains (6 frontal, 4 sagittal, 4 horizontal series, stained by the combined cell-fibre-method after KLUVER and BARRERA and by the method for myelined fibres after HEIDENHAIN). 2. The mammillary body of cattle is connected with four main fibre systems. These are the fornix and the mamillary peduncle as well as the mamillo-thalamic and the mamillo-tegmental tracts. 3. The fornix system first of all represents a rich myelined fibre connection between the hippocampus and the mamillary body. But also fornix fibres entering the poor-myelined regions of the hypothalamus and the mesencephalon have been demonstrated. 4. The mamillary peduncle ascending from the mesencephalon can be traced to the lateral mamillary nucleus. 5. The mamillo-thalamic tract of cattle has its origin in the mamillary body with the mamillotegmental tract associated to a common principal mamillary tract and passes to the complex of the anterior nucleus of the thalamus, while the mamillo-tegmental tract branching off from it curves into the mesencephalon.

Animals↗
PubMed1978

Connective tissue activation. XIII. Stimulation of sulfated glycosaminoglycan synthesis in human connective tissue cells by peptide mediators from lymphocytes and platelets.

CTAP-I from lymphocytes and CTAP-III from platelets markedly stimulated 35SO4= incorporation into chondroitin 4/6 sulfate and dermatan sulfate synthesized by human synovial, dermal, and cartilage connective tissue cells in vitro. These agonists promoted synthesis of the GAG carbon chain as well as sulfate incorporation. Both RNA and protein synthesis were required for these mediators to be effective in stimulating synthesis of connective tissue matrix components. A major part of the capacity of normal serum to stimulate sulfate incorporation into GAG's may reside in CTAP-III.

Blood Platelets↗
PubMed1978

Free serum ribonucleoprotein in mixed connective tissue disease and other connective tissue diseases.

Free ribonucleoprotein (RNP) was found by means of a hemagglutination inhibition assay in 21 sera from 11 of 25 patients with mixed connective tissue disease (MCTD) who had 299 sera studied. Free RNP tended to appear when anti-RNP antibody titers fell or when prednisone was initiated or increased. Five of 72 SLE patients (211 sera) had free RNP in at least one serum. Three of them had anti-RNP antibodies in other sera. Free serum RNP was found in one of 20 patients with scleroderma and in two of seven patients with connective tissue disease "overlap" syndromes without anti-RNP.

Antibodies, Antinuclear↗
PubMed1975

Some connections of the entorhinal (area 28) and perirhinal (area 35) cortices of the rhesus monkey. III. Efferent connections.

In this investigation the efferent projections of the entorhinal and prorhinal cortices relative to their sites of termination in the hippocampus and fascia dentata were investigated in the rhesus monkey using experimental silver impregnation methods. Contrary to the often cited observations of Lorente de No, all entorhinal areas, including the laterally lying prorhinal cortex, were found to give rise to the perforant pathway, and furthermore, each cytoarchitectonically defined subarea was found to contribute a unique component. These perforant pathway components terminate in distinct regions of the dendritic zones of the fascia dentata granule cell and the hippocampal pyramidal cell. A previously undescribed projection to the prosubiculum and hippocampus has been found to originate from the prorhinal cortex which forms the medial wall of the rhinal sulcus along the lateral-most portion of the entorhinal cortex in the rhesus monkey. These results, in conjunction with our previous observations regarding differential afferents to the entorhinal cortex, indicate that specific afferent and efferent connections characterize each cytoarchitectonically definable subareas of this periallocortical region. Additionally, they indicate that the perforant pathway might be conceptualized as the final link in a multisynaptic series of connections instrumental in providing the hippocampus with potential modality specific and multimodal input.

Animals↗
PubMed1976

Molecular connectivity V: connectivity series concept applied to density.

The concept of the expanded series of the connectivity index, chi, is introduced and applied to a consideration of the density of three classes of molecules. Correlations are found using two terms in the expanded series. A preliminary reflection on the extended series terms is made. It is noted that the regression equation constant in the three studies is close to the phase volume, 0.7402, and the possible significance of this fact is discussed.

Alcohols↗
PubMed1977

Retrograde axonal transport of 125I-tetanus toxin as a tool for tracing fiber connections in the central nervous system; connections of the rostral part of the rat neostriatum.

After previous studies had shown that 125I-tetanus toxin is taken up with high efficiency by all (adrenergic, sensory and motor)peripheral nerve terminals and that it is transported retrogradely by intraaxonal transport to the corresponding cell bodies, the present experiments were designed to investigate whether 125I-tetanus toxin could be used as a tool for retrograde tracing of fiber connections in the central nervous system and how the results obtained compared with other available retrograde tracing methods. Three to 12 h after injection of 125I-tetanus toxin into the rostral part of the nucleus caudatus of the rat, heavily labeled nerve cells were found in the substantia nigra zona compacta, in Forel field H2 and parts of the zona incerta, and in specific thalamic intralaminar nuclei (nucleus medialis pars lateralis and nucleus parafascicularis). Moderately labeled neurons were observed in the nucleus ventralis thalami and its dorsomedial part, in the nucleus raphe dorsalis and in the frontal, cingular and occipital cortex. Besides the labeling by retrograde transport, orthograde transport of radioactivity occurred in a striatonigral system. The high sensitivity and reliability of this method, even after injection of very small amounts of protein in a very small volume, represent important advantages over most of the commonly used tracing methods.

Animals↗
PubMed1976

Molecular connectivity. 6. Examination of the parabolic relationship between molecular connectivity and biological activity.

The topologically derived, nonempirical molecular connectivity index, chi, for several classes of compounds is shown to be parabolically related to the biological activities of these compounds. Similar nonlinear relationships were previously shown between the octanol-water partition coefficients, expressed as log P, of the compounds and their biological activities. These and previous studies indicate that many physiochemical properties presently used in structure-activity studies may be intermediaries between the nonempirical molecular structure encoded in chi and measured biological activities.

Amines↗
PubMed2026

Childhood Trauma and Frontoparietal Network Connectivity During Working Memory Task Performance in Individuals With Schizophrenia and Healthy Participants.

Schizophrenia is associated with altered frontoparietal connectivity, which supports higher-order cognition, including working memory. Childhood trauma has been linked to altered functional connectivity and reduced cognitive performance in individuals with schizophrenia and controls. Prior evidence suggests that trauma-related default mode dysconnectivity mediates the association between trauma and cognition. We hypothesised that childhood trauma would be associated with altered frontoparietal connectivity during a working memory task and that such connectivity changes would mediate the relationship between trauma and working memory. Childhood trauma, working memory and fMRI data were collected from individuals with schizophrenia or schizoaffective disorder (n = 38) and controls (n = 128). fMRI data were preprocessed in CONN, and seed-based connectivity analyses were performed for four frontoparietal seeds (bilateral dorsolateral prefrontal and posterior parietal cortices). Connectivity was contrasted across (a) diagnosis and (b) trauma severity. Moderated mediation analyses tested the associations between trauma, connectivity and working memory, with diagnosis as a moderator. Across all participants, higher physical neglect severity predicted poorer working memory performance. Stronger inverse connectivity between left dorsolateral prefrontal and frontal medial cortices predicted better working memory performance. As expected, patients showed widespread frontoparietal dysconnectivity relative to controls, but no differences in frontoparietal connectivity were observed across trauma severity groups. Frontoparietal connectivity did not mediate the association between trauma and working memory, although diagnosis moderated both the trauma-connectivity and connectivity-cognition associations. We conclude that, unlike previous evidence suggesting a mediating role for the default mode network, frontoparietal connectivity did not mediate the trauma-cognition association, possibly suggesting the unique significance of default mode network dysconnectivity in linking trauma to cognition in psychosis.

Humans↗
PubMedDate not supplied

Cardiac connections: the segmental approach to radiologic diagnosis in congenital heart disease.

The segmental approach to the diagnosis and classification of congenital heart disease, which emphasizes the importance of the connections (proximal-to-distal relationships) of cardiac chambers and great vessels, is presented. The radiologic identification of great vessels and cardiac chambers and their connections is described, considering, in turn, three major segments: the atria together with the systemic and pulmonary veins, the ventricles with their atrioventricular valves and the great arteries with their outflow tracts. Cardiac and great vascular connections can be described with greatest clarity by using the atria as the starting point. The atrial situs is defined as solitus, inversus or ambiguus, the great veins connecting to the atria normally or anomalously. The ventricles may be connected to the atria in concordant or discordant fashion or a double inlet ventricle may be present. The ventriculo-arterial connections can be classified as normal, transposition, double outlet right ventricle or double outlet left ventricle. The angiocardiographic techniques and criteria that differentiate these connection disorders and identify the transitional cases between them are discussed and illustrated. A complete diagnosis must indicate not only the connections of the three major segments but also the malformations and abnormalities of spatial position that may be present. Certain associations are of value in predicting the positions and connections of the cardiac chambers and great vessels, making it possible to formulate helpful rules to aid the progress of a diagnostic study. The fallibility of such rules is discussed, emphasizing the need to define connection disorders in terms of the connections rather than in terms of malformations or of abnormalities in spatial position of the individual parts.

Angiocardiography↗
PubMed1978

[New results on ageing of connective tissue (author's transl)].

Some new results on ageing of connective tissue are demonstrated, regarding not only mesenchymal, but also parenchymal organs of human and rat (both sexes). These results show that ageing of connective tissue is more a dynamic process (with measurable metabolic parameters of the several connective tissue cells and their products) than a passive or so-called degenerative connective tissue process. The bradytrophy concept of connective tissue cannot be accepted any longer. Then connective tissue cells can produce metabolic rates of the same level like parenchymal cells. The different organs possess partly common basic processes partly differences in connective tissue ageing, dependent on the composition and patterns of proteoglycans resp. of GAG and collagen types, furthermore dependent on localisation, structure and function. The results on ageing of connective tissue are useful for better understanding of ageing processes of parenchymal organs. Then their ageing is influenced essentially by the ageing of the own connective tissues. The turnover, more than the number of mesenchymal and parenchymal cells, decreases with ageing. More old than young cells seem to exist in old tissues and organs. The performance of ageing connective tissue cells can be constant or increase or decrease. Many mesenchymal and parenchymal organs develop a so-called "ageing-fibrosis".

Aged↗
PubMed1977

Immunopathology of skeletal muscle. The value of direct immunofluorescence in the diagnosis of connective tissue disease.

Whitaker and Engel in 1972 first described immunoglobulin deposition in muscle biopsy specimens in connective tissue disorders. In order to confirm and extend their observations and in the hope of identifying features that may differentiate skeletal muscle involvement in connective tissue diseases from other neuromuscular diseases, a series of 80 muscle biopsy specimens were examined using direct immunofluorescence. Three distinctive direct immunofluorescence patterns consisting of vascular, sarcolemma-basement membrane, and fiber staining were identified in skeletal muscle biopsy specimens from 35 patients, 31 of whom had a connective tissue disease. A vascular staining pattern showing a granular deposition of immunoglobulin or complement was seen in 15 patients, all of whom had a connective tissue disease. Routine stains generally did not reveal vessel abnormalities. A sarcolemma-basement membrane staining pattern was demonstrated around the sarcoplasmic membrane in 29 cases. Twenty-six of these patients had a connective tissue disease. There was no correlation with inflammation, fiber necrosis, or degree of connective tissue replacement. Fibers staining for immunoglobulin or complement, seen in 14 cases, generally occurred in morphologically normal fibers. Thirteen of these patients had a connective tissue disease. Since the pathologic change in muscle in the collagen vascular diseases often consists of the nonspecific findings of focal fiber necrosis frequently without inflammatory infiltrates, direct immunofluorescence may be useful in the diagnosis and classification of muscle diseases in the collagen vascular disorders. Furthermore, the findings of immunoglobulin deposition either within vessels or within individual muscle fibers suggest that immunological mechanisms may be responsible for muscular abnormalities in the connective tissue diseases.

Basement Membrane↗