On the role of astrocytes in epilepsy: a functional modeling approach.

In the present research, we extend a biologically plausible cortical neural population model (CPM), which was developed previously in the literature, by integrating the functional role of astrocytes in the synaptic transmission in the model. In other words, the original CPM is modified to consider neuron-astrocyte interaction. Then, two modified CPMs (MCPMs) are coupled via excitatory synapses; the astrocytes are also coupled through gap junctions. Using the coupled MCPMs (CMCPMs), it is demonstrated that the healthy astrocytes provide appropriate feedback control in regulating neural activity. As a result, the astrocytes compensate the coupling variations between CPMs in order to maintain the normal level of synchronized behavior. Next, malfunction of astrocytes in the regulatory feedback loop as one of the plausible causes of seizures is investigated. In this way, dysfunctional astrocytes are not any more able to regulate the excessive increase of the inter-population coupling strength. Consequently, disruption of the homeostatic function of astrocytes may initiate the hypersynchronous firing of neurons. This suggests that the neuron-astrocyte interaction may represent a novel target to develop effective therapeutic strategies for epilepsy.