Similarities and Differences of Acute Nonconvulsive Seizures and Other Epileptic Activities following Penetrating and Ischemic Brain Injuries in Rats

Abstract The similarities and differences between acute nonconvulsive seizures (NCS) and other epileptic events, for example, periodic epileptiform discharges (PED) and intermittent rhythmic delta activities (IRDA), were characterized in rat models of penetrating and ischemic brain injuries. The NCS were spontaneously induced by either unilateral frontal penetrating ballistic-like brain injury (PBBI) or permanent middle cerebral artery occlusion (pMCAO), and were detected by continuous electroencephalogram (EEG) monitoring begun immediately after the injury and continued for 72 h or 24 h, respectively. Analysis of NCS profiles (incidence, frequency, duration, and time distribution) revealed a high NCS incidence in both injury models. The EEG waveform expressions of NCS and PED exhibited intrinsic variations that resembled human electrographic manifestations of post-traumatic and post-ischemic ictal and inter-ictal events, but these waveform variations were not distinguishable between the two types of brai...