Generalization of seizures parallels the formation of "dark" neurons in the hippocampus and pontine reticular formation after focal-cortical application of 4-aminopyridine (4-AP) in the rat.

Distribution and time course of the occurrence of "dark" neurons were compared with the EEG activity and behavior of rats during 4-aminopyridine (4-AP) induced epileptic seizures. A crystal of the K(+) channel blocker 4-AP (0.5 mg/kg) was placed onto the exposed parieto-occipital cortex of Halothane-anesthetized rats for 40 min. Thereafter, the anesthesia was discontinued and the behavioral signs of the epileptic seizure activity were observed. The presence of "dark" neurons was demonstrated by the sensitive silver method of Gallyas in rats sacrificed at 0, 3 and 6 h after the end of the 4-AP crystal application. The EEG activity was recorded in the rats with longer survival times. The EEG analysis revealed the generalization of the epileptic seizures. We found that the formation of "dark" neurons in the hippocampus and the pontine reticular formation paralleled the generalization of the seizures

Strict Forest Reserve Research in the Margin of the Carpathians, the Vár-hegy Case-Study

Sixteen forest reserves are situated in the northern part of Hungary which belongs to the Carpathian region according to EURAC delimitation (Ruffini et al. 2006). These Hungarian forest reserves expand the natural forest remnant/forest reserve net of the Carpathians towards the lower hilly region, representing the deciduous beech and oak forest belts near their lower (xeric) distribution limits. This paper outlines the Hungarian forest reserves belonging to the Carpathian region and the preliminary results of current projects in the Vár-hegy Forest Reserve (Bükk Mts., Hungary) as a case study. The alteration of tree species composition was investigated here based on the reconstruction of forest history in the previous 130 years (management period) and analyses of forest stand inventory. In another project CO2 sequestration changes of these forest stands were modeled since the clear-cutting in the 1880th and carbon stored in the forest ecosystem compartments was estimated. Our results show that the forest reserve stands are presently in a transition state from the managed forest towards a more natural mixed forest with several age-classes