Neuromodulation within in vitro Neural Network Dynamics

Neuromodulation impacts oscillatory activity within cortical and hippocampal circuits and these oscillations have been shown to be important for cognitive processes such as working memory and attention. The synchronized activity that underlies these oscillations is a manifestation of the collective activity within large assemblies of neuronal populations and is due to fluctuations between the excitatory and inhibitory balance. These neural populations exhibit changes in the cells’ electric membrane potential, integrating to collective bursting dynamics. The oscillatory states are indicative of information transmission within the neural circuit and to examine changes in information transmission, we perform extracellular recordings of action potentials from cultured hippocampal neuronal networks using an array of microelectrodes. We perturb the excitatory/inhibitory balance within the network using pharmacological agents. We show a time-dependent effect on bursting dynamics after application of one of these agents and will discuss two possible mechanisms that may be involved.  Lastly, we present findings of a persistent increase in bursting dynamics in the presence of a neuromodulator and we suggest a target mechanism for its role.