Precipitating brain insults (ie, febrile seizures, local infections, SE, ischemia, or trauma) in concert with genetic susceptibility factors are thought to trigger such persistent changes. As explained above, to directly address this issue in human subjects is extremely

difficult. In recent years, check details investigators have therefore increasingly turned to animal models for this purpose. In the case of TLE, most investigators have studied epileptogenesis after an initial SE. It is important to realize that TLE models replicate the chronic features of TLE reasonably well. It is however not clear how much Inhibitors,research,lifescience,medical the mechanisms underlying SE-induced epileptogenesis overlap with the mechanisms underlying epileptogenesis in TLE patients, in whom this process is likely multifactorial and not triggered by SE. Nevertheless, Inhibitors,research,lifescience,medical studies

of epileptogenesis in SE models have been worthwhile because they have resulted in an increased understanding of the basic mechanisms underlying key features of AHS, such as sprouting, cell death, and gliosis. It may seem easier to establish models of epileptogenesis in symptomatic epilepsies, Inhibitors,research,lifescience,medical for instance epilepsy associated with CNS tumors, developmental malformations, or CNS trauma, for the simple reason that the initial precipitating injury is known, and can be replicated quite well in many cases. However, developing such models has proven surprisingly elusive. Models for tumor-associated epilepsy are scarce, and have relied on the injection of rapidly proliferating tumor cell lines into the

brain of rodents.12 While potentially valuable to assess the consequences of a rapidly growing malignancy Inhibitors,research,lifescience,medical in the CNS, these models are probably not that informative on mechanisms of epileptogenesis and seizure generation involved in human epilepsy patients. This is mainly because the tumors that are likely to cause epilepsy are mostly low-grade tumors with slow proliferation. The reasons for this association are unknown. It will be necessary to create additional models aimed at replicating features of these tumors. Regarding developmental malformations, there are several Inhibitors,research,lifescience,medical models in which the proper formation of cortical structures has been disrupted. These include models tuclazepam in which drugs are applied during cortical development that arrest neuronal migration, or in which lesions are applied to the cortex during cortex formation, which also lead to formation of a cortex with a disturbed laminar organization.13 In trauma models, fluid percussion injury results in a circumscribed traumatic cortical injury zone.14 These models have been informative because they have revealed manifold changes in excitability in and surrounding the abnormal cortical areas, and address the underlying mechanisms. However, it is not yet clear if these models lead to symptomatic epilepsy. More recently, genetic models of cortical malformations have been introduced.