Electrical Activity of the Exposed Human Brain

The application of electrical methods to the study of cerebral function is still in an experimental stage. In 1923 Grant,¹using a simple Wheatstone bridge arrangement, reported marked diminution in the electrical resistance of tumor tissue as compared with that of normal brain. Berger²amplified electric potentials set up in the brain and ascribed changes in potential to nervous activity. Foerster and Altenburger³succeeded in recording characteristic changes in potential in several cases of tumor of the brain. Subsequently, electroencephalographic methods have resulted in the accumulation of a considerable amount of data, especially with respect to the epileptic syndromes.⁴Recently, important contributions to the possibility of localization of tumors by electroencephalography⁵have been made. However, in only a few instances (notably, those of Foerster and Altenburger,³in Germany, and Walter, in England) have direct records from the cortex been demonstrated. We believed that studies