Subcortical epilepsy?

Departments of Medicine (R.A.B.B., S.J.V., M.J.C.) and Electrical and Electronic Engineering (R.A.B.B.), The University of Melbourne, Melbourne
Neurology (Impact Factor: 8.29). 05/2013; 80(20):1901-7. DOI: 10.1212/WNL.0b013e3182929f4f
Source: PubMed


In the past, the cortex has for the most part been considered to be the site of seizure origin in the different forms of epilepsy. Findings from histopathologic, electrophysiologic, and brain imaging studies now provide ample evidence demonstrating that like normal cerebral function, epileptic seizures involve widespread network interactions between cortical and subcortical structures. These studies show that different forms of generalized and focal epileptiform discharges and seizures engage various subcortical structures in varying ways. This interaction has been the subject of many reviews and is not the focus of the current work. The aim of this review is to examine the evidence suggesting the possibility for some of the subcortical structures to initiate seizures independently and the clinical implications of this.

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Available from: Mark James Cook

  • No preview · Article · Oct 2013 · Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology
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    ABSTRACT: Rats with brain dysplasia evoked by interruption of different stages of prenatal neurogenesis show characteristic variations in susceptibility to seizures depending on the neurochemical specificity of pharmacological agents used to evoke seizures. To verify a discrepancy between the data obtained using different pharmacological models, neurochemically neutral electroshocks were applied here. To produce brain dysplasia of different degrees, pregnant Wistar rats were exposed to a single 1.0Gy dose of gamma rays on gestation days 13, 15, 17 or 19. From the postnatal day 60, their male offspring (E13s, E15s, E17s and E19s, respectively) were subjected to 21 daily electrical stimulations to evoke seizures. Profiles of tonic and clonic reactivity to electrical stimulation significantly differed from those observed following pilocarpine or kainic acid administration. E17s showed minimal intensity of tonic but maximal of clonic responses. On the contrary, very high tonic and low clonic reactivity was observed in E13s and E15s. Periventricular nodular heterotopias (PNHs) were observed exclusively in E15s and E17s. Generally, the size of PNHs was correlated positively with susceptibility to tonic seizures but negatively with susceptibility to clonic seizures. Analogous correlations with the size of the neocortex were opposite. E13s and E19s had brains devoid PNHs but showed high tonic seizure susceptibility similar to that in E15s. It can therefore be concluded that PNHs modified the type of seizure reactivity from tonic to clonic, depending of their size, but the presence of PNHs was not necessary for the development of seizure susceptibility itself.
    Full-text · Article · Oct 2013 · Epilepsy research
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