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ImpAct Teams

EQUIPE 1

Motor representations can be described at different levels of action organization. A large neural network, such as motor cortex, posterior parietal cortex, the basal ganglia and cerebellum contributes to their generation. These motor representations are particularly important for action planning, motor programming and movement trajectory control. Our projects aim to study 1) the different motor variables, the different spatial reference frames and the underlying neural substrates needed to elaborate the different levels of motor representations; 2) the influence of external or internal constraints of action for the organization of basic movements; 3) the various action modalities that lead to the implication of different types of motor representations, to the development of flexibility and/or adaptation, and to the generalization of adaptation mechanisms; 4) the clinical aspects of motor representation deficits and their therapeutic applications.

EQUIPE 2

Spatial Representations are central to sensori-motor processes. Indeed, the representation of the goal precedes the elaboration of motor representations and any motor act modifies the relationship between the body and space and hence the spatial representations. This interaction is particularly obvious for eye movements in which the retinal localization of a target is systematically modified by a saccade and a remapping of spatial representations is necessary to compensate for this unstability. Attention is an additional parameter of this interaction between sensory and oculomotor processes via internal representations of space. Our project aims to study the relationships between 1) the oculo-motor mechanisms, 2) visuo-spatial attention and 3) the dynamic spatial representations which continuously need to be updated based on sensory and motor information. This complex triad of processes contributes to visual perception and visuo-motor guidance of action in peripersonal space. Our project aims at determining the substrate underlying these three components and understand how they co-operate for perception and action. Clinically, the achievement of such a theoretical model would also favour a better care of the acquired neurological handicaps or developmental disorders in children.

EQUIPE 3

Multisensory integration is a new central issue in cognitive neurosciences. Although originally addressed from a ‘purely’ visual perspective, both motor and spatial representations rely heavily on multisensory processing mechanisms. This team’s project aims at revealing the processes of multisensory interaction (both integration and competition) involved in the planning and control of action, as well as in the development of spatial and bodily representations. A major project of this team is to elucidate the functional role played by visuo-tactile interaction in the control of action, by making the hypothesis that it serves the control of object-oriented actions. The project will determine the dynamic properties, as well as the neurophysiological bases of these visuo-tactile representations and their links with the action production mechanisms. The fundamental knowledge collected in humans and animals (development of a model of visuo-spatial deficits like extinction and neglect) will finally be exploited in a perspective of rehabilitation of cognitive disabilities.

Transversal themes

The study of motor flexibility is one major activity of our laboratory since 20 years. This theme has continued to develop since 2000, owing to the development of functional neuroimaging and neuropsychological approaches conducted on neurological patients. The implementation of motor flexibility protocols in the “Movement and Handicap” platform allows Team 1 to intensify the clinical investigations and explore new neurological diseases. An original aspect of this project is to propose the exploitation of motor flexibility of the hand to promote motor recovery in hemiplegic patients. Flexibility is central also to Team 2, who investigates the role of the Posterior Parietal Cortex in manual and ocular responses to sudden changes of the target position during movement execution. Team 3 focuses on multisensory aspects of the motor flexibility during prehension movements.

Brain plasticity is also a central research topic of our laboratory across the three teams’ projects. The manifestation of plastic phenomena will be studied by means of visuo-motor adaptation protocols (at ocular and limb level), as well as in the course of the functional recovery period in neurological patients. The level(s) at which this kind of plasticity takes place in the visuo-motor system is still poorly understood and highly debated. The potential effects of such plastic phenomena at higher levels of spatial representations are also central to this research topic, as they may have therapeutic implications at the level of the spontaneous recovery after brain injury and by potentially promoting the functional recovery and compensation for sensori-motor disabilities.