Since the development of the ion specific liquid ion exchanger microelectrode (Walker, 1971), investigators have established that the resting potassium ion activity in the cortex of various animals (rat, cat, rabbit, guinea pig) is within the range of 2.5 mM/liter to 3–5 mM/liter (Vyskocil, et al, 1972), (Lux, et al, 1972), (Lux and Neher, 1973), (Prince, et al, 1973), (Futamachi, et al, 1973), (Mutani et al, 1973), (Morris, 1973), CKirshner, et al, 1975), and (Dora and Zeuthen, 1975). The response of cortical potassium ion activity during hypoxia (Morris, 197ft), (Kirshner, et al, 1975) and anoxia (Vyskocil, et al, 1972), (Morris, 1974), (Dora and Zeuthen, 1975) has also been well established. For the past several years our interest has been directed toward experimentally and theoretically characterizing the dynamic response of the cerebral cortex to various stimuli. These studies have been directed toward describing the response to hypoxia and anoxia in both the adult and the fetus (Guilbeau, et al, 1977), (Smith, et al, 1977), (Reneau, et al, 1977).KeywordsCardiac ArrestCell Membrane PermeabilityEnzyme ElectrodeVenous CirculationExtracellular PotassiumThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.