Precise synchronization dynamics in cortical networks – feasibility and constraints

Studies of cortical network function on the basis of multiple single-neuron recordings have revealed neuronal interactions which depend on stimulus and behavioral context. These interactions exhibit dynamics on several different time scales, with time constants down to the millisecond range (Grün et al. 2002a,b, Gütig et al. 2002, 2003, Heck et al. 2002, Riehle et al. 1997, Vaadia et al. 1995). Mechanisms underlying such dynamic network organization are investigated by experimental and theoretical approaches. Our current research focuses on two interrelated aspects: precision and variability of cortical network activity (Arieli et al. 1996, Nawrot et al. 2000, 2003). Starting from previous model work (Diesmann et al. 1999, Gewaltig et al. 2001) in which we investigated conditions for the occurrence of precise joint-spiking events in cortical network activity, I will present recent findings from ongoing experimental and theoretical work in our laboratory (Heck et al. 2000, Hehl et al. 2001, Kuhn et al. 2002, 2003, 2004, Mehring et al. 2003), undertaken to test and expand some of the model predictions. Specifically, I will discuss new findings regarding the feasibility and constraints of precise synchronization dynamics in cortical networks, resulting from a critical evaluation of biological constraints from cortical connectivity and in vivo physiology, and dynamical constraints from large-scale network simulations. Funded by GIF. Further information at http://www.brainworks.uni-freiburg.de