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  • 1
    Electronic Resource
    Electronic Resource
    Analysis of an inventory of information systems in the public administration (1996)
    Springer
    Requirements engineering 1 (1996), S. 47-62 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01235765
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Tetrodotoxin induced calcium spikes: in vitro and in vivo studies of normal and deafferented Purkinje cells (1991)
    Springer
    Experimental brain research 84 (1991), S. 297-302 
    Details
    ISSN: 1432-1106
    Keywords: TTX ; Purkinje cell ; Cerebellum ; Deafferentation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tetrodotoxin (TTX) is widely used to block the sodium dependent action potential in excitable cells to study their other ionic properties. TTX applied outside, selectively blocks voltage dependent sodium channels and is thought to have no other effects. We report here that TTX, applied to slices of rat cerebellum, suppressed sodium spikes of the Purkinje cells and induced firing in bursts of slower spikes. This activity was blocked by cobalt (2 mM) or cadmium (0.2 mM) in the medium as well as by hyperpolarizing currents showing that the slow spikes were due to voltage dependent calcium channels. The membrane potential was not significantly changed by TTX and the spikes during the bursts had the same threshold potentials and peak spike amplitudes as the voltage and Ca2+ dependent dendritic spikes evoked by injected current before adding TTX. This indicated that no marked changes in the membrane conductances were produced by the TTX. Unlike the burst firing induced by removing extracellular sodium, the TTX induced bursts were not followed by a large hyperpolarization. The same kind of results were obtained with extracellular recording in the in-vivo preparation with TTX applied topically or by pressure near the recording sites. TTX induced burst firing was not due to blocking afferent inhibitory input to the PC, since bicuculline (10-6 M) applied without TTX, produced only increased firing of fast action potentials and no bursts. The bursts could be arrested within 1 to 2 min by intravenously administering 2 mg/kg sodium pentobarbital, the blockage lasted from 5 to 15 min. These effects of TTX were not due to a contaminant as TTX from two different suppliers produced the same effects. A possible mechanism based on a decrease of intracellular free sodium is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231449
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Cerebellar output response to afferent stimulation: Energy consumption and unit activity in the cat fastigial nucleus (1983)
    Springer
    Experimental brain research 52 (1983), S. 400-410 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00238033
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Harmaline-induced tremor (1981)
    Springer
    Experimental brain research 42 (1981), S. 383-391 
    Details
    ISSN: 1432-1106
    Keywords: Harmaline ; Tremor ; Interposito ; Rubral system ; Oculomotricity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Units were recorded extracellulary in the cat brainstem under the effect of tremogenic doses of harmaline. They were localized post mortem and the units discharging at the harmaline tremor frequency were mapped. Harmaline-sensitive neurons were found in the bulbo-pontine reticular formation, in particular, in the lateral reticular nucleus and the nucleus reticularis tegmenti pontis. The nucleus interpositus as well as the red nucleus also displayed numerous units discharging at the tremor frequency, indicating that the cerebello-interposito-rubro-spinal system controlling the flexor muscles participate in harmaline tremor. Participation of the oculomotor system in the harmaline-induced tremor was tested at the level of the vestibular neurons relaying the vestibulo-ocular reflex, the motoneurons, the eye muscles and the eye movements. No rhythmic discharge at the tremor frequency nor eye movements could be detected, indicating that harmaline tremor does not affect the oculomotor system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237503
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Harmaline-induced tremor (1981)
    Springer
    Experimental brain research 42 (1981), S. 371-382 
    Details
    ISSN: 1432-1106
    Keywords: Harmaline ; Tremor ; Inferior olive ; Cerebellum ; Deoxyglucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Changes of local cerebral glucose consumption under the effect of tremogenic doses of harmaline were studied. To find the brain structures activated by the drug, the autoradiographic method using [14C]2-deoxyglucose was applied to young cats. After administration of harmaline, the animals were paralized with flaxedil. Results were compared to a group of control animals not injected with the drug, but submitted to the same experimental protocol. Increases of neuronal activity were observed in several structures. A) Among the relays of the olivo-cerebellofastigio (and vestibulo)-reticulo-spinal circuit that had been claimed to fire at the frequency of the tremor, labeling was found in: 1. selected portions of the inferior olive including the medial accessory olive and the caudolateral part of the dorsal accessory olive; 2. the molecular layers of the cerebellar cortex including vermian and paravermian zones. Labeling of the olivo-cerbellar system was therefore larger than the compartment controlling the fastigial nucleus and extended to that controlling the interpositus nucleus. B) Other structures not under the direct control of the olivo-cerebellar system displayed increased radioactivity under harmaline: lateral reticular nucleus, nucleus reticularis tegmenti pontis, red nucleus and basal ganglia. Part of nucleus ambiguus, intensely labeled in the control animals, showed decreased radioactivity under harmaline. The experiments were repeated with the same protocol in another group of animals with unilateral sections of the inferior cerebellar peduncle in order to distinguish between a direct pharmacological influence and a nervous one. Marking of the basal ganglia was not affected by pedunculotomy, suggesting a direct “pharmacological” action of the drug in this cases. On the other hand, marking of the other labeled structures was asymmetric or suppressed by pedunculotomy, and therefore could result from a “nervous” effect secondary to activation of the inferior olive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237502
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    Paper (German National Licenses)
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