NETWORKS | Network Interactions in the Limbic System and Epileptiform Synchronization

Neuronal networks in the hippocampal and parahippocampal regions are damaged in patients affected by temporal lobe epilepsy (TLE). The consequences of the lesions are still poorly understood, but evidence suggests that interactions between the entorhinal cortex (EC) and hippocampus are changed from polysynaptic to monosynaptic, bypassing the CA3 region. In addition, the perirhinal/postrhinal cortex (PC), which normally filters the signals entering the hippocampal formation, may lose its capacity to inhibit the paroxysmal neuronal activity directed to or leaving the EC. Finally, emphasis has recently been placed on the epileptogenic role of the subiculum that is disinhibited both in epileptic animals and in TLE patients.