STUDY OF HUMAN CEREBRAL BIOPSY SPECIMENS IN AN ELECTRICALLY EXCITED CONDITION

MEANS of electrically stimulating the metabolism of separated cerebral tissues have recently been developed in these laboratories.* The methods render such tissue much more susceptible to a wide variety of agents than are unstimulated tissues.3 and metabolic lesions, otherwise unapparent, may thus be detected. The methods are applicable to a few milligrams of tissue taken as biopsy specimens or during neurosurgical operations. They have not yet found a routine use, but their value in research is indicated by the following account, which describes briefly some results previously reported and adds others hitherto unpublished.A separated fragment of the mammalian cerebral cortex is electrically inert when examined by techniques which reveal profuse and intricate electrical activity in the brain in situ. A few seconds only after such a fragment has been removed from the brain, not only will it give no electrical response to applied electrical pulses, but also the