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  • Efferent cerebellar neurones  (2)
  • Conceptual schema analysis  (1)
  • Fastigial nucleus, [14C]-2-deoxyglucose  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Requirements engineering 1 (1996), S. 47-62 
    ISSN: 1432-010X
    Keywords: Conceptual schema analysis ; Information system re-engineering ; Reference components ; Similarity measures ; Schema clustering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The paper deals with the problem of building an inventory of information systems for the public administration, with reference to an ongoing project in Italy. We describe the investigation techniques defined for collecting information and the techniques developed for a systematic analysis of the large set of conceptual schemas resulting from the investigation. These schemas describe the data used by the public administration work processes. In particular, we describe the conceptual schema of the inventory, which is the basis for discussing the methodology of investigation, the choice of units of investigation, the data collection and merging, and the access to information. Then, we present the schema analysis techniques developed to analyse semi-automatically the large set of conceptual schemas resulting from the investigation. In particular, we illustrate indexing techniques for identifying representative descriptors of schemas and similarity techniques to compare schemas for their classification into families. Finally, the tool developed to support the storage, analysis and classification of schemas is described and experimentation results are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 57 (1985), S. 370-380 
    ISSN: 1432-1106
    Keywords: Inferior olive ; Purkinje cells ; Efferent cerebellar neurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cerebellar units were recorded extracellularly in rats before and after an intraveinous injection of 3-acetylpyridine destroying selectively the IO. All the Purkinje cells show a loss of the complex discharge between 2 h 15 min and 2 h 45 min after treatment. This time, called the “critical period” corresponds to the degeneration of the neurons of the inferior olive as revealed by the decrease of their metabolic activity. The simple spikes of the Purkinje cells increase their discharge frequency soon after the climbing fibers cease firing. On the contrary the firing frequency of the inhibitory interneurons does not show significant changes after degeneration of the inferior olive. The efferent cerebellar neurons, including cells of the cerebellar and vestibular nuclei receiving the axon terminals of the Purkinje cells, decrease their discharge rate up to thirty times during and after the critical period. It is demonstrated that this effect is due to the increased inhibitory activity of the Purkinje cells deafferented from the climbing fibers, whereas the deafferentation of the efferent cerebellar neurones from the collaterals of the olivary cells has little impact.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 59 (1985), S. 404-409 
    ISSN: 1432-1106
    Keywords: Cerebellar inhibition ; Inferior olive ; Efferent cerebellar neurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The long term effects of inferior olive destruction on the activities of the Purkinje cells and their target neurones in the cerebellar nuclei were studied in the rat. Careful observations were also made of motor behaviour throughout the study. Albino rats were injected with 3-acetylpyridine to produce a neurotoxic destruction of the inferior olive and then were used for acute recording experiments at 1–2 days, 5–7 days, 12–18 days, 35–38 days, 75–97 days and 230–252 days. After degeneration of the inferior olive, there was an initial period lasting for a few days, characterized by a high firing frequency of Purkinje cells associated with a very low level of activity of the neurones in the cerebellar nuclei. During this period, there was a deep depression of motor activity. A period of adaptation follows during the first month, characterized by a slow recovery of the initial firing frequency of the cerebellar units and a gradual recovery of spontaneous locomotion; nevertheless the firing pattern and motor behaviour remain abnormal. From one month on the unit activities disturbances and the motor deficiencies stabilize. The hypothesis is advanced that Purkinje cell inhibition on their target neurones, which increases during the initial period, gradually diminishes during the adaptation time, and then stabilizes to a subnormal state.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1106
    Keywords: Cerebellum ; Fastigial nucleus, [14C]-2-deoxyglucose ; Unit activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cerebellar output function was studied using cerebellopetal proprioceptive stimulation hich produces simple and complex excitatory discharges as well as inhibitory activity in the Purkinje cells. The activity of the intracerebellar nuclei (and of the entire brain stem) was measured by the energy consumption as revealed with the [14C]-2-deoxyglucose method. The stimulations consisted of repetitive (1–20 c/s) electrical excitation of the nerve leading to the inferior oblique, to the masseteric and to the gastrocnemius soleus muscle. Compared to a group of non-stimulated controls, heavy bilateral labeling was obtained in the posterior pole of the fastigial nucleus. This was not observed with stimulation of the vibrissal pad which, however, produced a clear increase of [14C]-2-deoxy glucose uptake in the secondary trigeminal complex. Labeling of the posterior part of the fastigial nuclei was suppressed by ablation or pharmacologic inactivation of the overlying cerebellar cortex which suppresses the inhibitory activity of the Purkinje cells into the nuclear cells. Labeling of the posterior fastigial nuclei was also decreased in animals not stimulated but with ablation or pharmacologic inactivation of the overlying cerebellar ortex. The hypothesis proposed is that the marking results are the consequence of an increased activity in the Purkinje cell terminals. The activity of the Purkinje cells was also recorded extracellulary both before and during repetitive stimulation of a muscle nerve. The discharge activity of those in the cerebellar vermis and giving axons to the posterior fastigial nucleus was increased by the stimulation, whereas the activity of those of the hemispheral parts remained unchanged. Units in the fastigial nucleus were also recorded. Their activity was found to be deeply depressed so that only a few units were encountered and no further decrease of their discharge could be detected with the stimulation of a muscle nerve. Nevertheless, using the present data and those previously obtained, the conclusion is advanced that the cerebellar output function is actually decreased during afferent cerebellar stimulation.
    Type of Medium: Electronic Resource
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