In August of 1991, a second Dartmouth International Workshop on the corpus callosum was convened to share and discuss the progress that had been made over the decade that had passed following the first workshop. A nucleus of basic and clinical scientists came together to discuss their work and the work of others in a field that has been broadened clinically by the addition of many new centers throughout the world that are now performing corpus callosotomy for intractable epilepsy. This text was stimulated by the participants' presentations and associated fertile discussions. It is compiled from the conference and subsequent studies. It reflects, both at the basic and clinical level, an important and expanding field of neural science endeavor. In keeping with the present and rapidly expanding field of outcomes assessment, callosotomy is again evaluated in light of a further decade of surgery and follow-up. Callosotomy continues to be a useful, palliative procedure and the indications for its use have been better established. The basic science section is a supplement to the first edition and elaborates progress in both new data and ideas. The section on experimental epilepsy models adds further support to the clinical rationale for callosotomy. Perhaps of greater importance is the contribution of experimental models to our understanding of the propagation of seizure activity. The section on the neuropsychology of the split brain patient demonstrates the continuing major contributions to the understanding of brain and behavior that pour forth from this cornucopia.

In August of 1991, a second Dartmouth International Workshop on the corpus callosum was convened to share and discuss the progress that had been made over the decade that had passed following the first workshop. A nucleus of basic and clinical scientists came together to discuss their work and the work of others in a field that has been broadened clinically by the addition of many new centers throughout the world that are now performing corpus callosotomy for intractable epilepsy. This text was stimulated by the participants' presentations and associated fertile discussions. It is compiled from the conference and subsequent studies. It reflects, both at the basic and clinical level, an important and expanding field of neural science endeavor. In keeping with the present and rapidly expanding field of outcomes assessment, callosotomy is again evaluated in light of a further decade of surgery and follow-up. Callosotomy continues to be a useful, palliative procedure and the indications for its use have been better established. The basic science section is a supplement to the first edition and elaborates progress in both new data and ideas. The section on experimental epilepsy models adds further support to the clinical rationale for callosotomy. Perhaps of greater importance is the contribution of experimental models to our understanding of the propagation of seizure activity. The section on the neuropsychology of the split brain patient demonstrates the continuing major contributions to the understanding of brain and behavior that pour forth from this cornucopia.

InJuly 1982 the first Dartmouth workshop on the corpus callosum took place. A nucleus of basic and clinical scientists was convened to give progress reports of their work on the corpus callosum. This text was subsequently compiled by the various participants from these reports modified by a stimulating cross fertilization of ideas and subsequent studies. Four and one-half decades have intervened since Van Wagenen first sectioned the corpus callosum for epilepsy (Van Wagenen and Herren, 1940) and Erickson (1940) demonstrated that the corpus callosum is the major route for generalization of experimentally induced focal cortical epilepsy. During the succeeding 45 years a handful of clinicians has pursued these leads to confirm the therapeutic value of callosotomy for some types of medically intractable generalized epilepsy. Parallel experimental studies with a number of epilepsy models have indicated that the corpus callosum is indeed the major route for seizure generalization, that the brainstem is a secondary and more resistant pathway for seizure generalization, and that most if not all epileptic seizures originate from the cerbral cortex. The unexpected clinical finding that even partial (focal) seizure incidence is modified by callosotomy now has been demonstrated in the laboratory. The various contributors to the clinical and experimental epilepsy sections of this volume have been seminal in these elucidations, as will be evident from their chapters. The section on the development, anatomy, and physiology of the corpus callosum demonstrates that these basic areas of study have not been neglected.