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  • 1
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have identified a novel mouse gene named pancortin that is expressed dominantly in the mature cerebral cortex. This gene produces four different species of proteins, Pancortin-1-4, sharing a common region in the middle of their structure with two variations at the N-terminal (A1 or A2 part) and C-terminal (C1 or C2 part) sides, respectively. In the present study, we showed that expression of mRNAs for A2-Pancortins (Pancortin species that contain the A2 part, i.e., Pancortin-3 and -4) is more dominant than that of mRNAs for A1-Pancortins (Pancortin species that contain the A1 part, i.e., Pancortin-1 and -2) in the prenatal mouse cerebral neocortex. Using western blot analysis, we found that substantial amounts of both A2-Pancortins were present in the prenatal cerebral neocortex and P19 cells after inducing neuronal differentiation. A2-Pancortins were still present in the cerebral neocortex of the adult, although their mRNAs were hardly detected. In contrast, the amount of A1-Pancortins did not increase after the third postnatal week in spite of their intense gene expression. Furthermore, we showed that recombinant Pancortin-3, one of the A2-Pancortins, was a secreted protein, in contrast to Pancortin-1 (one of the A1-Pancortins). These results suggest that A2-Pancortins are extracellular proteins essential for neuronal differentiation and that their molecular behavior is distinct from that of A1-Pancortins.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 89 (2004), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The dorsal column-medial lemniscal system is a significant sensory pathway that mediates touch and limb position sense. In this system, axons from the second-order neurons in the dorsal column nuclei form the internal arcuate fibers, cross the ventral midline (floor plate) within the medulla oblongata, and then project to the thalamus as the medial lemniscus. Here we demonstrate that Netrin-1, which is secreted from the floor plate in the medulla oblongata, is indispensable to the formation of the dorsal column-medial lemniscal system. Axons from the dorsal column nuclei cross the midline at around embryonic day 11 in mice. Concurrently, Netrin-1 mRNA and its receptor DCC (deleted in colorectal cancer) were expressed in the floor plate and commissural axons there, respectively. In our explant culture experiments, the floor plates of the embryonic 11-day-old mutant Netrin-1 homozygous mice did not attract axons from the dorsal column nuclei of ICR mice, while those from the wild type littermates did. Moreover, we observed that although the dorsal column nuclei developed in situ in mutant mice, their axons were not attracted toward the floor plate: they did not cross midline and remained ipsilaterally, without forming the internal arcuate fibers, in embryonic 17-day-old mutant Netrin-1 homozygous mice.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1436-2813
    Keywords: Breast cancer ; stage II ; randomized study ; modified radical mastectomy ; extended radical mastectomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A controlled cooperative study was carried out to assess the value of modified radical mastectomy for patients with stage II breast cancer. The data was analyzed from 11 institutions in the Shikoku District participating in a prospective clinical trial in which patients were randomly assigned either to a modified radical mastectomy group or an extended radical mastectomy group. These two groups of patients were similar to each other in terms of such background factors as age distribution, menopausal status, TNM classification, tumor size, location of the primary tumor, axillary nodal involvement, histological type, and estrogen receptor status. The median follow-up times in the modified and extended radical mastectomy groups were 4.7 and 4.5 years, respectively. The cumulative curves indicated no difference between the two groups in either disease-free survival or overall survival. The survival rates were classified according to the presence or absence of axillary nodal metastases. However, no significant difference was found between the two groups. These findings thus suggest that the routine removal of the grossly uninvolved major pectoral muscle and parasternal lymph nodes is not necessary in patients with stage II breast cancer.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 38 (1980), S. 103-105 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract A neural network model is proposed for the understanding of the receptive field properties of the complex cell. The model is based on recent neurophysiological findings on the visual cortical network. The model is proved to be functionally identical with Hubel's and Wiesel's hierarchy model though the two models are structurally quite different.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 32 (1979), S. 1-8 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract A neural network model is proposed to explain the development of direction selectivity of cortical cells. The model is constructed under the following three hypotheses that are very plausible from recent neurophysiological findings. (1) Direction selectivity is developed by modifiable inhibitory synapses. (2) It results not from the direct convergence of many excitatory inputs from LGN cells but from cortical neural networks. (3) Direction-selective mechanism is independent of orientation-selective mechanism.—The model was simulated on a computer for a few kinds of inhibitory connections and initial conditions. The results were consistent with neurophysiological facts not only for normal cats but for cats reared in an abnormal visual environment.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 73 (1995), S. 401-407 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract We first present a mathematical analysis of the relation between the parameters and the behavior of the basic module in the proposed neural network model for visual motion detection. Based on the analytical results, a learning rule is put forth that can develop velocity selectivity of directionally selective cells in the basic module. The learning rule is furthermore introduced into the total model called a ‘mass model’, which is constructed with many basic modules. Numerical simulation results showed that each basic module in the mass model learned in a self-organizing manner to acquire selectivity for the velocity of an input stimulus. The proposed learning rule would be plausible in the actual nervous system in that it is simple and can be described with only local information.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 73 (1995), S. 401-407 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract.  We first present a mathematical analysis of the relation between the parameters and the behavior of the basic module in the proposed neural network model for visual motion detection. Based on the analytical results, a learning rule is put forth that can develop velocity selectivity of directionally selective cells in the basic module. The learning rule is furthermore introduced into the total model called a ‘mass model’, which is constructed with many basic modules. Numerical simulation results showed that each basic module in the mass model learned in a self-organizing manner to acquire selectivity for the velocity of an input stimulus. The proposed learning rule would be plausible in the actual nervous system in that it is simple and can be described with only local information.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 68 (1993), S. 247-252 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract This paper proposes a new neural network model for visual motion detection. The model can well explain both psychophysical findings (the changes of displacement thresholds with stimulus velocity and the perception of apparent motion) and neurophysiological findings (the selectivity for the direction and the velocity of a moving stimulus). To confirm the behavior of the model, numerical examinations were conducted. The results were consistent with both psychophysical and neurophysiological findings.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 29 (1978), S. 75-82 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract The function of Golgi cells in the cerebellar cortex is quantitatively examined in consideration of the nonlinear input-output characteristics and convergence and divergence numbers of cells. It is strongly suggested that the two signal paths to Golgi cells have different function. The feed-forward path will have the same function as assumed in the previous theories of the cerebellar cortex, that is, to keep the firing rate of granule cells approximately constant over considerable variation in the firing rate of mossy fibers. The feedback path will, on the other hand, have a new function which has not been assumed in the previous theories. The function is to cause oscillation of the firing rate of granule cells for stationary mossy fiber inputs. The assumption of the new function enables us to explain cerebellar function to keep stationary posture.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 40 (1981), S. 195-200 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract On the basis of recent neurophysiological findings on the mammalian visual cortex, a selforganizing neural network model is proposed for the understanding of the development of complex cells. The model is composed of two kinds of connections from LGN cells to a complex cell. One is direct excitatory connections and the other is indirect inhibitory connections via simple cells. Inhibitory synapses between simple cells and complex cells are assumed to be modifiable. The model was simulated on a computer to confirm its behavior.
    Type of Medium: Electronic Resource
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