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  • 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 42 (1981), S. 383-391 
    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
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  • 3
    ISSN: 1432-1106
    Keywords: Metabolism ; Intracerebellar nuclei ; Inferior olive
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Metabolic activity of the intracerebellar nuclei during cryoinactivation of the inferior olive was studied in the anaesthetized rat by using the 14C-2-deoxyglucose method. Single unit recording of Purkinje cells was simultaneously monitored in the cerebellar cortex. Local inactivation in the inferior olive resulted in regional suppression of complex spike discharges in the cerebellar cortex. An increased metabolic activity was observed in the cerebellar nuclei contralateral to the cryoinactivation site correlating the somatotopically arranged olivo-cerebello-nuclear circuit. This increase was shown to be due specifically to inactivation of the inferior olive, since it was not obtained in a rat in which the inferior olive was previously destroyed by neurotoxic doses of 3-acetylpyridine. The results are interpreted as being due to an increased presynaptic activity of the terminals of the Purkinje cells which fire simple spikes at high rates after climbing fibre deafferentation.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1106
    Keywords: Vestibular ; Ocular ; Optokinetic ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Dynamic characteristics of the horizontal vestibulo-ocular reflex (HVOR), the optokinetic response (OKR), and their interactions were investigated in alert albino rabbits. For stimulation of the horizontal semicircular canals, the whole rabbit was rotated sinusoidally on a motor-driven turntable at peak-to-peak amplitudes of 5 ° to 30 ° over a frequency range of 1/30 to 1/2 Hz. Optokinetic stimulation was provided by a narrow vertical slit light source presented in front of the eye to be tested. The evoked horizontal eye movements were observed and measured by means of a closed circuit television system adapted to provide an analog signal proportional to the eye movement. The net HVOR was obtained by rotation of the turntable in darkness and the net OKR by rotation of the light source. Combining rotation of the turntable with a stationary light source immediately increased the gain and reduced the phase shift of the HVOR. The light source moving in phase with the turntable, but at twice the angular amplitude, reduced the gain and advanced the phase of the HVOR. Eye movement curves of the HVOR modified by a fixed or moving slit light could be reconstructed approximately by a linear combination of the net HVOR and OKR.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 42 (1981), S. 371-382 
    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
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 26 (1976), S. 407-422 
    ISSN: 1432-1106
    Keywords: Climbing fibers ; Inferior olive ; Brain stem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The sources and pathways of the climbing fibers to the cerebellar posterior vermis were studied with combined electrophysiological and anatomical methods in cats. Recording from identified cerebellar Purkinje cells, monosynaptic climbing fiber (CF) responses have been obtained both for stimulation of the inferior olive (IO) and various parts of the brain stem (BS). CF responses were found to be of three types, IO only, BS only or both IO and BS. However the responses to BS stimulation were very few in number in comparison with IO or IO and BS types of responses. The latencies of the responses were shorter for the BS cases consistent with their distance from the cerebellum. A comparison of latencies and the relative responsiveness of the different area of the brain stem which were studied, indicate that part of the CF ascend through the pontine region and enter the cerebellum by way of the medium and superior peduncles. This finding is confirmed by the results of anatomical studies in which degenerating fibers were found in the molecular layer (using the Nauta technique) after lesion of the brachium pontis but not after lesions of the medial portion of the pons. Similarly, injection of radioactive leucine into the pontine nuclei failed to show any labeled fibers in the molecular layer. Horseradish peroxidase (HRP) was injected into localized regions of the posterior vermis after total bilateral destruction of the inferior peduncles. Large numbers of positive, marked cells were still found in the inferior olive. It is concluded that nearly all, if not all, the climbing fibers originate in the inferior olive and that they ascend to the cerebellum by way of all the peduncles.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1106
    Keywords: Masticatory muscles ; Extraocular muscles ; Mesencephalic nucleus ; Semilunar ganglion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Horseradish peroxidase has been injected in the masticatory and extraocular muscles in newborn and adult cats to identify the cells of origin for the muscle endings. Labeled motoneurons in the nuclei of the III, IV, V and VI nerves have been observed. They are the parent cells of the motor terminals taking up the enzyme in the muscle injected. Labeled ganglionic cells have been found scattered all along the ipsilateral mesencephalic nucleus of the V nerve after injection of both the jaw closing and the jaw opening muscles. Labeled cells have also been found in the ipsilateral caudal part of the same nucleus after injection of the extraocular muscles. These results are interpreted as due to enzyme uptake by the sensory endings of the muscle studied. Moreover cell bodies in the semilunar ganglion were found marked for both groups of muscles injected showing a second ganglionic representation for the sensory endings.
    Type of Medium: Electronic Resource
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  • 8
    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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  • 9
    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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  • 10
    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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