Effect of acute elevated magnesium on bursting activity and information-processing dynamics in cortical cultures

Abstract

Magnesium (Mg2+) plays a significant role in hippocampal memory and learning and is implicated in a variety of neurological disorders, such as migraine. Despite this crucial role Mg2+ has on brain health, its effect on the dynamics of networks of neurons is still not fully understood. This study investigates the impact of several doses of elevated extracellular Mg2+ on cortical organotypic cultures. Cultures were recorded on a 512-microelectrode array and analyzed using the burstiness index (BI), the rate of network-wide bursts relative to other neuronal activity. We also use a suite of information theoretic measures to further establish the role Mg2+ plays in the brain. Elevated Mg2+ is found to have a dose-dependent increase on BI caused by a loss of network activity not contained within a burst or high firing rate activity. Information dynamics further show that the network experiences a loss of entropy and an increase in time-reversibility, connectivity, and transfer of redundant information. These factors indicate that Mg2+ causes a loss of complex activity and an increase in highly integrated, constant dynamics. This lays the groundwork for a deeper examination of the role Mg2+ plays in learning, memory and treating neurological disorders.