Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 14: Neuronal and Sensory Systems

BP 14.3: Vortrag

Mittwoch, 25. März 2009, 14:45–15:00, HÜL 186

Eye dominance induces pinwheel crystallization in models of visual cortical development — •Lars Reichl¹, Siegrid Loewel², and Fred Wolf¹ — ¹Max-Planck-Institute for Dynamics and Self-Organization, Goettingen — ²Institute of General Zoology and Animal Physiology, University Jena

The formation of orientation preference maps during the development of the visual cortex is sensitive to visual experience and impulse activity. In models for the activity dependent development of these maps orientation pinwheels initially form in large numbers but subsequently decay during continued refinement of the spatial pattern of cortical selectivities. One attractive hypothesis for the developmental stabilization of orientation pinwheels states that the geometric relationships between different maps, such as the tendency of iso-orientation domains to intersect ocular dominance borders at right angles can prevent extensive orientation map rearrangement and pinwheel decay. We present a analytically tractable model for the coupled development of orientation and ocular dominance maps in the visual cortex. Stationary solutions of this model and their dynamical stability are examined by weakly nonlinear analysis. We find three different basic solutions, pinwheel free orientation stripes, and rhombic and hexagonal pinwheel crystals locked to a hexagonal pattern of ipsilateral eye domains. Using amplitude equations for these patterns, we calculate the complete stability diagram of the model. In addition, we study the kinetics of pinwheel annihilation or preservation using direct numerical simulations of the model.