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Morphological asymmetry of the frontal operculum and temporal planum becomes measurable at the 29th week of gestation. There is evidence of subsequent differential development of the planum in favor of the left, with the left planum larger than the right. While both the frontal operculum and left planum were always present, the right planum ranged in size from absent (10%)to larger than the left (about 10%). Females predominated (P less than .05) in the latter group. The findings suggest that (1) a higher percentage of persons may have right-sided cerebral representation for speech than has been assumed previously; (2) a predetermined morphological asymmetry contributes to establishing the ultimate pattern of cerebral speech representation following an early insult to a predisposed hemisphere; and (3) it is necessary to scrutinize clinical material for the differential organization of hemispheric development between sexes.

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Summary Daily unilateral electrical stimulation of initially subconvulsive amygdala resulted in progressive development of seizures (kindling) in cats, culminating in generalized convulsive seizures of focal onset that could occur spontaneously. Kindled cerebral epileptogenicity persisted for up to 12 months and was characterized by (1) interictal spike discharges of consistent morphology and localization, and (2) an “all or none” response to stimulation at the generalized seizure triggering threshold. Pentylenetetrazol (Metrazol) enhanced the frequency of interictal discharge without changing its localization or morphology, and caused generalized seizures with focal onset exactly like those produced by unilateral stimulation of the amygdala. These findings indicate that repeated electrical stimulation of amygdala produces widespread alteration of brain function resulting in a permanent state of epileptogenicity. Kindling thus qualifies as an experimental model reminiscent of certain types of human epilepsy. RÉsumé La stimulation électrique quotidienne de l'amygdale qui était initialement subconvulsive donnait lieu progressivement à des crises (“sensibilisation,” kindling) aboutissant à des crises convulsives à début focal secondairement généralisées, et pouvant survenir spontanément. Cet état de sensibilisation cérébrale prédisposant à l‘épilepsie, persiste jusqu’à 12 mois et se caractérise (1) par des décharges intercritiques de pointes de morphologie et localisation constantes, et (2) par une réponse de type “tout ou rien”à une stimulation seuil déclenchant des crises généralisées. Le pentylenetetrazol (Metrazol) augmente la fréquence des décharges de pointes intercritiques sans toutefois modifier leur topographie et leur morphologie et provoque des crises à début focal avec généralisation secondaire exactement identiques a celles produites par la stimulation unilatérale de l'amygdale. De telles donnees indiquent que des stimulations électriques répétées de l'amygdale produisent une altération cérébrale diffuse, responsable d'un état permanent d‘épileptogénicité. Cet état (“kindling”) se pose done comme un modéle expérimental qui rappelle certaines formes d’épilepsie chez I'homme. RESUMEN La estimulación eléctrica unilateral de una amígdala, previamente subconvulsiva, produjo el desarrollo progresivo de ataques en gatos, culminando en ataques generalizados de comienzo focal, que podían ocurrir espontaneamente. Este tipo de epileptogénesis “provocada” (“kindling”= eneender) persiste hasta 12 meses y se caracteriza por (1) descargas interictales de puntas de morfología y localización persistente, y (2) una respuesta “todo o nada” con estimulación a umbrales que desencadenan ataques generalizados. El pentilenetetrazol (Metrazol) aumentó la frecuencia de interictales de puntas sin modificar su localizacion o morfología y produjo ataques generalizados de comienzo focal idénticos a los producidos por estimulación unilateral de la amígdala. Estos hallazgos indican que la estimulación repetida de la amígdala produce a...

We describe an epileptic syndrome of bilaterally coordinated limb movements, axial movements, vocalization, and nonmasticatory oral activity. EEG and physiologic evidence indicates the syndrome is caused by ictal discharge in the mesial frontal lobes. Two of 12 patients were not helped by anterior temporal lobectomy, and 3 others improved after section of the anterior two-thirds of the corpus callosum.