Asymmetric Activity Waves in Synaptic Cortical Systems

This study explores asymmetric activity wave propagation in cortical systems, both experimentally and mathematically. Experimentally, we find that activity waves passing through the same neural tissue but in different directions exhibit different speeds and spatial profiles and evoke different firing patterns in individual neurons. Mathematically, we extend our previously published results on the existence of traveling pulse solutions to account for our experimental observations. Specifically, our analysis suggests that asymmetric connectivity is sufficient to account for asymmetric propagation. Moreover, it predicts that unidirectional propagation can occur in cases of extreme asymmetry. Finally, we experimentally validate our analytic findings by examining wave propagation in a cortical region where asymmetric coupling is known to exist.