The excitatory and convulsant actions of local anesthetics have been ascribed to a selective block of inhibition. Other studies cite the amygdala as the probable site of local anesthetic seizure initiation. We have recently observed that lidocaine increases the susceptibility of vestibular neurons to synchronization by repetitive stimuli. The objectives of this study are 1) to determine how local anesthetics block neuronal inhibition, 2) to test directly for possible block of inhibition in the amygdala by local anesthetics, 3) to determine if local anesthetics also increase the susceptibility of amygdala neurons to synchronization and 4) to assess the contribution of such actions to the genesis and propagation of local anesthetic seizures. Better understanding of how generalized convulsive seizures are produced by systemically administered local anesthetics may lead to improved procedures and agents for treating and preventing local anesthetic seizures.