Effects of brainstem and subcortical lesions on corticogenic epileptic convulsion with special reference to Forel h-field

An experimental study was attempted to make an analysis of the subcortical and brain stem lesion effect on the Metrazol-induced corticogenic epileptic convulsion based on EEG-discharge and EMG-convulsion as indicators. utilizing 42 adult cats. 1. A definite threshold increment of eliciting the seizure was found in the case of bilateral lesion of the Forel H-field. In contrast to it, no variation in the threshold was found in the case of the lesions at the other parts of brain stem, thalamus, red nucleus and its neighborhood, and lenticular nucleus. 2. There was a parallel relation between EEG discharge and convulsion. Dissociation could be obtained in none of the cases. 3. It is, therefore, to be concluded that the Forel H-field is composed of the main axis of cortico-subcortical reverberating circuit and that the lesion causes a decrement of the excitability at cortex and an inhibition of the corticogenic epileptic convulsion.