Georgios Is. Detorakis will defend his thesis at the Loria laboratory on Octber 23rd, 2013. The title is Cortical plasticity, dynamic neural fields and self-organization.

Jury

  • Nicolas Rougier (co-director)
  • Fréderic Alexandre (co-director)
  • Hugues Berry (reviewer)
  • Philippe Gaussier (reviewer)
  • Danisl Shulz (examiner)
  • Sylvain Contassot-Vivier (examiner)

Abstract.

The aim of the present work is the modeling of the formation, maintenance and reorganization of somatosensory cortical maps using the theory of dynamic neural fields. A dynamic neural field is a partial integro-differential equation that is used to model the cortical activity of a part of the cortex. Such a neural field is used in this work in order to model a part of the area 3b of the primary somatosensory cortex. In addition a skin model is used in order to provide input to the cortical model. From a computational point of view the model is able to perform distributed, numerical and adaptive computations. The model is able to explain the formation of topographic maps and their reorganization in the presence of a cortical lesion or a sensory deprivation, where balance between excitation and inhibition plays a crucial role. In addition, the model is consistent with neurophysiological data of area 3b. Finally, it has been shown that attention plays a key role in the organization of receptive fields of neurons of the somatosensory cortex. Therefore, in this work has been proposed a definition of somatosensory attention and a potential explanation of its influence on somatotopic organization through a number of experimental results. By changing the gains of lateral connections, it is possible to control the shape of the solution of the neural field. This leads to significant alterations of receptive fields sizes, resulting to a better performance during the execution of demanding haptic tasks.