Pallidotomy and Pallidoamygdalotomy in Certain Types of Convulsive Disorders

The importance of subcortical systems located as far down as the rhombencephalon for the propagation of corticofugal epileptic discharges became evident when it was demonstrated that the generalization of impulses originating in the motor cortex of one side was not prevented in dogs by median sagittal section of the prosencephalon, diencephalon, and mesencephalon (Spiegel and Falkiewicz⁴⁰). Furthermore, it is known that not only the pyramidal tract (Hering,²⁰ in experiments on dogs) but also all the fiber systems contained in the cerebral peduncles are dispensable for the centrifugal conduction of cortically induced discharges (von Economo and Karplus⁹ in cats). Thus, an extrapyramidal conduction of corticofugal impulses must play a significant part in the propagation of epileptic discharges; this was also suspected by Krisch,²⁸ on the basis of clinical observations. Important evidence in this direction has been presented by the recent experimental studies of Hayashi¹⁹ in dogs