BRAIN CHIMERAS IN BIRDS - APPLICATION TO THE STUDY OF A GENETIC FORM OF REFLEX EPILEPSY

A strain of chicken, called here FEpi (for Fayoumi epileptic), bearing an autosomal recessive mutation, exhibits a form of reflex epilepsy w ith EEG interictal paroxysmal manifestations and generalized seizures in response to either light or sound stimulations. By using the brain chimera technology, we demonstrate here that the epileptic phenotype c an be partially or totally transferred from an FEpi to a normal chick by grafting specific regions of the embryonic brain. The mesencephalon contains the generator of all epileptic manifestations whether they i nvolve visual or auditory neuronal circuits, with the exception of the abnormal EEG which is transmitted exclusively by telencephalic grafts . This analysis supports the hypothesis that certain forms of human an d mammalian epilepsies have a brainstem origin.