Research Grants

Award Year 2006

KALATSKY Valery
DINSE Hubert
Spatial and temporal dynamics of plasticity in adult visual cortex: High resolution imaging study

The visual system has been the model for much of our understanding of the mechanisms of neural function and plasticity. Primary visual cortex contains a complex topographic architecture, where the visual field is mapped topographically in addition to functional stimulus features such as orientation and direction of movement of a visual stimulus, and the input of the two eyes. While these features are subject to substantial adaptations in the developing brain, there is now growing evidence that these maps are even not hard wired in the adult brain. Understanding the mechanisms of this reorganization is very important for both basic sciences such as the remodeling of the underlying neuronal circuitry, and clinical applications (treatments for loss of function due to injury, diseases, and ageing). To get insight into the dynamics of adult map reorganization in visual cortex, we propose a joint effort through a combination of new optical imaging technologies with new protocols to induce and to study plastic reorganization by means of intracortical microstimulation. Both approaches have been shown independently to be feasible and effective, and because of accompanying perceptual changes behaviourally relevant. The proposed combination will allow studying the time course of plastic map changes continuously over many hours. This procedure will overcome a major shortcoming in conventional analysis of map plasticity, that rely on a simple comparison of a pre- and a post status. The joint approach will first be used to visualize the instant changes of orientation preference maps, and will then be used for an extended study of the putative joint changes of the different functional (orientation, direction, ocular dominance) and retinotopic maps, thereby providing insight into mechanisms that stabilize not only a single functional map, but also the complex arrangement of several overlaid representations. The approach integrates expertise in optical imaging, computational neuroscience, neurobiology of learning and plasticity.