Functional Alteration of Deep Structures in Cats with Chronic Focal Cortical Irritative Lesions

Introduction The significance of independent paroxysmal abnormalities²,¹⁷,²⁴,⁴⁵or multiple spike foci²⁷,⁴⁶in deep cerebral structures of some epileptics has not been clearly understood. The latter finding and relatively low "cure" percentage in his own series of surgical epileptic cases led Meyers to challenge seriously the conceptual basis of current day epilepsy surgery.²⁸Although the Montreal school³²reported a higher percentage of satisfactory results in a larger and carefully selected focal epilepsy population, the importance of further careful analysis of failure cases in surgery for epilepsy can not be overemphasized. Possible reasons for surgical failure may be (1) incomplete excision of the cortical focus or (2) location of the original focus in the depth rather than on the surface. Such possibilities have received substantial support from both clinical and experimental studies. A further possibility is that an independent secondary deep abnormality might be produced by long-standing bombardment