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In vivo, in vitro, the bridge may not be too far after all...| old_uid | 2330 |
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| title | In vivo, in vitro, the bridge may not be too far after all... |
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| start_date | 2007/03/05 |
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| schedule | 11h-12h30 |
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| online | no |
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| summary | The neuronal operations underlying motor control have been the object of intense studies. Extracellular recordings in behaving animal have been used to assess the function of various subgroups of neurons. Morphological and electro-anatomical methods have led to a precise description of their connectivity. Post-spike trigger averaging and intracellular injection of dyes in the alert animal have been useful to link morphological results with functional data. Finally, this experimental knowledge was used to investigate theoretical models, which satisfactorily describe the neuronal computations necessary to motor control. Nevertheless, an important, and often implicit hypothesis is that motor control relies on the emerging properties of the neuronal networks that are under investigation. However, this assumption may not be correct. Indeed, in vitro studies on slices have demonstrated that individual neurons of vertebrates have non-linear membrane properties, which give them complex integrative properties. Hence, for motor control in vertebrates, the respective contribution of the emerging properties of a network as opposed to the specific properties of its individual components, i.e. the neurons (and the glial cells), is still basically open to question. It is clear that to address these issues a combination of various complementary neurobiological methods in different types of in vivo and in vitro preparations is required.
This talk illustrates some of the successes and failures we have encountered by using such a strategy to explore gaze and postural control in the rodent as a model of motor control. In particular we will illustrate how the emerging network properties are the basis of the change of coordinates from an exocentric frame of reference of the sensorial afferents to an intrinsic frame of reference for motor commands. In contrast we will show that the intrinsic membrane properties specify the dynamics of the neuronal networks at play by specifying frequency-tuned channels. Finally we will investigate how these two types of mechanisms contribute to the post lesional plasticity of the central nervous system with distinct time course. |
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| responsibles | Information non disponible |
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