Generalized Epilepsy: Neurobiological Approaches

In recent years there has been intense interest in the basic mechanisms of epilepsy. Many symposia and monographs have been devoted to this topic. These reviews, however, have focused almost exclusively on studies performed in models of partial (or focal) epilepsy. It was natural that scientists interested in the fundamental mechanism of epileptogenesis at the cellular level were attracted to work on models in which the epileptogenic dysfunction could be confined to ever-smaller populations of neurons. Many of the most illuminating studies done in this field in the recent past have been carried out in vitro on brain slices or on dissociated neuronal cultures. Much valuable insight into the mechanisms of epileptogenesis has been obtained in this manner. One cannot, however, automatically assume that mechanisms elucidated in such exquisitely "focal" models are applicable to forms of epilepsy in which seizures from their very start involve the entire brain. One of the most difficult questions that arises in this context is how epileptogenic dysfunction, which can be understood in terms of mechanisms involving a few contiguous cells, can lead to what appears to be a simultaneous onset of seizure discharge in virtually all areas of the brain. Most of the workers who have made excellent contributions to the understanding of the cellular mechanisms involved in epileptogenesis have paid virtually no attention to this important problem.

Table of Contents:
1 Historical Introduction.- I Clinical Background.- 2 The Syndromes of Generalized Epilepsy.- 3 Unanswered Clinical Questions in Generalized Epilepsy.- 4 The Relationship Between Sleep Spindles and Spike-and-Wave Bursts in Human Epilepsy.- II Fundamental Cellular and Neurotransmitter Mechanisms.- 5 Membrane Properties of Cat Betz Cells Studied In Vitro.- 6 Changes in Extracellular Ions Associated with Epileptiform Discharges.- 7 Role of Neurotransmitters in the Genesis of Epileptiform Discharges.- 8 Excitant Amino Acids in Epilepsy.- 9 Possible Epileptogenic Consequences of Misused GABAergic Relationships.- 10 Anticonvulsant Effects of Intracortical Chronic Infusion of GABA in Generalized Epilepsy.- 11 In Vitro Electrophysiology of a Genetic Model of Generalized Epilepsy.- III Thalamic and Cortical Mechanisms in Absence Attacks.- 12 Spindling, Incremental Thalamocortical Responses, and Spike-Wave Epilepsy.- 13 Physiology of Thalamic Relay Neurons: Properties of Calcium Currents Involved in Burst-Firing.- 14 Thalamo-Cortical Relationships in Generalized Epilepsy with Bilaterally Synchronous Spike-and-Wave Discharge.- 15 Focal and Generalized Epileptiform Activity in the Cortex: In Search of Differences in Synaptic Mechanisms, Ionic Movements, and Long-Lasting Changes in Neuronal Excitability.- 16 Pharmacology of the Inhibitory Systems in Primary Generalized Epilepsy of “Petit Mal” Type.- 17 Spontaneous Spike-and-Wave Discharges in Wistar Rats: A Model of Genetic Generalized Conconvulsive Epilepsy.- 18 Behavioral and Electrophysiological Studies of Absence Epilepsy.- IV Photosensitivity.- 19 Focal Discharges in Photosensitive Generalized Epilepsy.- 20 Photosensitive Epilepsy of the Baboon: A Generalized Epilepsy with a Motor Cortical Origin.- 21 Role of Dopamine inGeneralized Photosensitive Epilepsy: Electroencephalographic and Biochemical Aspects.- 22 Inferences Regarding the Visual Precipitation of Seizures, Eye Strain, and Headaches.- V Generalized Convulsive Seizures.- 23 Animal Models of Generalized Convulsive Seizures: Some Neuroanatomical Differentiation of Seizure Types.- 24 Mechanisms Underlying Generalized Tonic-Clonic Seizures in the Rat: Functional Significance of Calcium Ions.- 25 Substantia Nigra-Mediated Control of Generalized Seizures.- 26 Mesencephalic Structures and Tonic-Clonic Generalized Seizures.- VI Metabolic and Neurochemical Studies.- 27 Metabolic Studies of Generalized Epilepsy.- 28 PET Studies of Generalized Epilepsy Induced by Convulsant Drugs Acting at the GABA-Benzodiazepine Receptor Complex.- 29 Postictal Compensatory Changes in Cortical Alpha-1 Receptors and Adrenergic-Mediated Phosphoinositol Metabolism Following Repeated Electroconvulsive Seizures in Rats.- VII Pharmacological Agents and Generalized Seizures.- 30 Cellular Actions of Petit Mal Anticonvulsants: Implication of Thalamic Low-Threshold Calcium Current in Generation of Spike-Wave Discharge.- 31 Mechanisms of Anticonvulsant Action of Valproate: An Overview and Perspective.- 32 Sedative Drug Withdrawal Seizures: Cellular Electrophysiological Mechanisms.