RT Book, Section A1 Galanopoulou, Aristea S. A1 Moshé, Solomon L. A2 Duchowny, Michael A2 Cross, J. Helen A2 Arzimanoglou, Alexis SR Print(0) ID 1138409311 T1 Networks and Systems in Epileptic Seizures T2 Pediatric Epilepsy YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9780071496216 LK accesspediatrics.mhmedical.com/content.aspx?aid=1138409311 RD 2024/03/28 AB Epileptic seizures are stereotypical patterns of abnormal synchronized activity among different cellular populations. They are products of pathological activation of networks involved in controlling the temporal (initiation, maintenance, termination) or semiological evolution of these ictal events. Often seizure activity forms a reverberating circuit that can perpetuate and self-sustain, as is the case with temporal lobe seizures. Alternatively, a seizure can be paroxysmal but temporally confined, albeit with the potential to recur, such as in epileptic myoclonus or spasms. The basic elements of these networks may belong to a single or multiple systems, which are recognized based on well-identified physiological functions. As such, they are useful in localizing seizure activity and defining seizure propagation. Communications within a system or between different systems, during a seizure, can be via anatomical connections (i.e., afferent or efferent neuronal projections) or humoral (i.e., hormonal, metabolic or immune responses). A sine qua non of epilepsy is the propensity for unprovoked seizures to recur. In certain cases, this is already a predetermined feature of the original epileptic seizure network, as occurs in certain types of primary idiopathic epilepsies, that is, absence. The expression of the seizures, in such cases, appears to depend more on modifiers involved in the physiological maturation of the network, such as age or hormonal factors. In other types of epilepsy, the epileptic predisposition is not as strong initially, but dynamic changes of the network triggered by seizures or unrelated epigenetic factors promote epileptogenesis. The classical example is temporal lobe epilepsy (TLE), whereby initial precipitating events may increase the likelihood that TLE will manifest.