Neuropathological Findings in Primary Generalized Epilepsy: A Study of Eight Cases

Abstract

On neuropathological investigation of eight cases with primary generalized epilepsy, none showed elective parenchymal necrosis, which is regarded (qualitatively and topologically) as characteristic of epilepsy in classical neuropathology. In seven of the eight cases, however, marked microdysgenesis with varying regional distribution was found. These maturation disturbances are to be interpreted as pathological and refute the currently held view that there is no evidence of pathological brain damage in primary generalized epilepsy.

Oligodendroglial Vacuolar Degeneration in the Bilateral Motor Cortices and Astrocytosis in Epileptic Beagle Dogs.

“…Montgomery and Lee have described an acute neuronal damage in many dogs of an epileptic beagle colony [12], and suggested that the cerebral cortex, basal nuclei, claustrum, amygdala, septai nuclei, dorsal thalamic nuclei, isthmus of the pyriform lobe and hippocampus were the most common areas affected. Similar findings have been observed in the cerebrum of eight human patients with primary generalized epilepsy [9]. We also observed ischemic neuronal changes in the cerebral neocortex, basal ganglia, claustrum, amygdala and thalamus as well as the hippocampus in one case showing a status epilepticus.…”

“…The oligodendroglial changes were not considered as an artifact but the pathological change since the changes were localized in some areas of cerebral cortex and accompanied marked astrocytosis. Although we cannot deny the possibilty that the oligodendroglial changes are a secondary change to epilepsy, we consider the expects as a primary change to epilepsy from the following two reasons; (1) the changes have not been found in the animals [1,2,7,14,18] and humans [9,10] sacrificed or died of epilepsy and (2) they are confined only in the motor area of the cerebral cortex. It is probable that some metabolisms of the oligodendrocytes in the bilateral motor cortices would be impaired and then that the disturbance of myelin formation occurred, resulting in the myelin pallor in the IV to VI layers, but since the oligodendroglial degeneration could not be identified in the motor cortex of one dog (case 3) with epilepsy, we could not define the significance of oligodendroglial change as a possible cause of epilepsy.…”

Distribution of EFHC1 or Myoclonin 1 in mouse neural structures

“…On the other hand, because of its association with the centrosome , a microtubule-organizing center (MTOC), that plays an important function in neuronal movement (Hatten, 2002) and by its co-localization with radial glia, it could influence neuronal progenitors migration. Therefore, we hypothesize that microdysgenesis and increased thickness of cortical grey matter found by MRI studies of JME patients (Meencke and Janz, 1984;Woermann et al, 1999) could result from defects in neuronal migration due to disruption of proteins that regulate microtubules in radial glia, like EFHC1.…”

Early history of subplate and interstitial neurons: from Theodor Meynert (1867) to the discovery of the subplate zone (1974)

“…In the context of temporal lobe epilepsy, interstitial neurons within white matter are usually described as heterotopic (Meencke & Janz, 1984;Hardiman et al 1988;Armstrong, 1993;Wolf & Weistler, 1993;Mischel et al 1995) and thought to represent one element of a group of developmental disorders frequently referred to as cortical dysplasia (Taylor et al 1971), glioneuronal hamartia (Wolf & Weistler, 1993), microdysgenesis (Meencke & Janz, 1984;Hardiman et al 1988;Armstrong, 1993) or heterotopia . Rojiani et al (1996) found that these 'residual ⁄ heterotopic neurons' were significantly more numerous in temporal than in frontal or occipital cortex, and concluded that they represent interstitial remnants of the subplate which have failed to undergo programmed cell death.…”