Berlin 2008 – scientific programme
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BP: Fachverband Biologische Physik
BP 3: Neuronal Systems
BP 3.2: Talk
Monday, February 25, 2008, 14:30–14:45, C 243
Reorganization of neural circuitry during growth of cat visual cortex — •Wolfgang Keil1,2,3, Fred Wolf2,3, Siegrid Löwel4, and Matthias Kaschube1 — 1Princeton University, Princeton, NJ USA — 2MPIDS, Göttingen, Germany — 3BCCN, Göttingen, Germany — 4Friedrich-Schiller-University, Jena, Germany
In cat visual cortex, the period of postnatal cortical growth largely overlaps with the period of enhanced plasticity, but little is known about the interrelation between these two phenomena. We analyzed the two-dimensional spatial organization of ocular dominance (OD) columns during postnatal cortical growth. Despite a size increase of 50% of area 17 between postnatal week 3 and 10, the mean spacing between adjacent OD columns increased only slightly. Consequently, the number of hypercolumns increased considerably during this expansion period. Furthermore, this process was paralleled by a strong tendency of columns to change appearance from stripe-like to disordered patterns. Theoretically, this process resembles a behavior known as the zigzag instability in dynamical systems. This is a generic behavior in expanding self-organizing systems dominated by Mexican-hat like interactions and is therefore predicted by a large class of models for activity dependent visual cortical development. We analyzed the effect of cortical expansion on columnar layouts in an Elastic Net model and compared it to the degree of reorganization observed experimentally. We find that the observed reorganization indeed exhibits signatures of this type of instability. Thus, these models indicate that the observed mode of columnar reorganization results from cortical expansion.