Search results for "Movement"
showing 10 items of 2021 documents
Cerebellar learning of bio-mechanical functions of extra-ocular muscles: modeling by artificial neural networks
2003
A control circuit is proposed to model the command of saccadic eye movements. Its wiring is deduced from a mathematical constraint, i.e. the necessity, for motor orders processing, to compute an approximate inverse function of the bio-mechanical function of the moving plant, here the bio-mechanics of the eye. This wiring is comparable to the anatomy of the cerebellar pathways. A predicting element, necessary for inversion and thus for movement accuracy, is modeled by an artificial neural network whose structure, deduced from physical constraints expressing the mechanics of the eye, is similar to the cell connectivity of the cerebellar cortex. Its functioning is set by supervised reinforceme…
Ultrastructure of putative migrating cells in the cerebral cortex of Lacerta galloti.
1986
Cells considered to be migratory in the cerebral cortex of adult lizards are ultrastructurally of two types. Nuclei in the first type have highly dispersed chromatin, creating a spongy appearance, whereas in the second type the chromatin is irregularly clumped. Both types of cells are closely associated with processes of radial ependymal glia cells, which perhaps orient their migratory pathways. Cells with spongy chromatin show an increase in cytoplasmic organelles and progressive chromatin condensation as they travel from the ependymal layer to the granular layer. Possibly these cells account for the neuronal increase that takes place in the granular layer during postnatal life. Cells with…
Lissencephalic syndromes: brain and beyond
2009
Lissencephaly has been long maintained a malformation involving only the brain. Classic lissencephaly includes agyria and pachygyria and it is the most severe form of malformations derived from abnormal neuronal migration. It is defined as a smooth or nearly smooth cerebral surface with absence of normal sulci and gyria. It encompasses a group of syndromes which show many different clinical conditions. Four groups are actually distinguished: classic lissencephaly variants, other lissencephalies including forms with unknown pathogenesis, microlissencephaly spectrum and Cobblestone cortical malformations. Several genes and proteins are involved in this syndromic spectrum and each year new mol…
Activity-Dependent Regulation of Neuronal Apoptosis in Neonatal Mouse Cerebral Cortex
2007
A massive neuronal loss during early postnatal development has been well documented in the murine cerebral cortex, but the factors that drive cells into apoptosis are largely unknown. The role of neuronal activity in developmental apoptosis was studied in organotypic neocortical slice cultures of newborn mice. Multielectrode array and whole-cell patch-clamp recordings revealed spontaneous network activity characterized by synchronized burst discharges, which could be blocked by tetrodotoxin and ionotropic glutamate receptor antagonists. The identical neuropharmacological manipulations also caused a significant increase in the number of apoptotic neurons as early as 6 h after the start of dr…
Making Waves: Initiation and Propagation of Corticothalamic Ca2+ Waves In Vivo
2013
Corticothalamic slow oscillations of neuronal activity determine internal brain states. At least in the cortex, the electrical activity is associated with large neuronal Ca(2+) transients. Here we implemented an optogenetic approach to explore causal features of the generation of slow oscillation-associated Ca(2+) waves in the in vivo mouse brain. We demonstrate that brief optogenetic stimulation (3-20 ms) of a local group of layer 5 cortical neurons is sufficient for the induction of global brain Ca(2+) waves. These Ca(2+) waves are evoked in an all-or-none manner, exhibit refractoriness during repetitive stimulation, and propagate over long distances. By local optogenetic stimulation, we …
The Effect of Taper and Apical Diameter on the Cyclic Fatigue Resistance of Rotary Endodontic Files Using an Experimental Electronic Device
2021
The aim of this study was to analyze the effect of the taper and apical diameter of nickel&ndash
Graphic Interpretation Eileen Gray and Charlotte Perriand
2015
The article deals with the study of two projects of Eileen Gray, an architect who had turned her perception of reality into formal delicacy and Charlotte Perriand, who was able to promote the emphasis of collective and rational living. The article proposes the “graphic re-interpretation” or redrawing of some unbuilt Eileen Gray and Charlotte Perriand’s projects designed in response to the social problems arising in 1936. Their projects of minimum temporary houses are a manifesto through which they investigates other principles of the Modern Movement with the variety of composition of small spaces in relation to the inside well-being at the human scale. The redrawing practice, shown in this …
Urban water quality modelling: a parsimonious holistic approach for a complex real case study
2010
In the past three decades, scientific research has focused on the preservation of water resources, and in particular, on the polluting impact of urban areas on natural water bodies. One approach to this research has involved the development of tools to describe the phenomena that take place on the urban catchment during both wet and dry periods. Research has demonstrated the importance of the integrated analysis of all the transformation phases that characterise the delivery and treatment of urban water pollutants from source to outfall. With this aim, numerous integrated urban drainage models have been developed to analyse the fate of pollution from urban catchments to the final receiving …
The action of TH17 cells on blood brain barrier in multiple sclerosis and experimental autoimmune encephalomyelitis.
2019
Th17 cells, known as a highly pro-inflammatory subtype of Th cells, are involved very early in numerous aspects of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) neuropathology. A crucial event for the formation and accumulation of MS lesions is represented by the disruption of the blood brain barrier (BBB) in relapsing-remitting MS. Th17 cells also contribute to the progression of MS/EAE. These events will allow for the passage of inflammatory cells into the brain. Secondary to this, increased recruitment of neutrophils occurs, followed by increased protease activity that will continue to attract macrophages and monocytes, leading to brain inflammation with sus…
Influenza A virus infection inhibits the efficient recruitment of Th2 cells into the airways and the development of airway eosinophilia.
2003
Abstract Most infections with respiratory viruses induce Th1 responses characterized by the generation of Th1 and CD8+ T cells secreting IFN-γ, which in turn have been shown to inhibit the development of Th2 cells. Therefore, it could be expected that respiratory viral infections mediate protection against asthma. However, the opposite seems to be true, because viral infections are often associated with the exacerbation of asthma. For this reason, we investigated what effect an influenza A (flu) virus infection has on the development of asthma. We found that flu infection 1, 3, 6, or 9 wk before allergen airway challenge resulted in a strong suppression of allergen-induced airway eosinophil…