137Essays on Infinite LifespansBrian Wowkbarbiturates, can flatten EEG (brain electrical activity) read-ings for many hours while still permitting later recovery. [10] This prolonged drug-induced elimination of brain activity is sometimes used as a treatment for head injuries. [11] Patients do not emerge from these comas as blank slates. Evidently human beings do not require continuous operation like com-puter chips. Brains store long-term memories in physical structures, not fleeting electrical patterns.Perhaps the most extreme example of brains completely stopping and later starting again are the experiments of Isamu Suda reported in the journal Nature [12] and elsewhere [13] in 1966 and 1974. Suda showed recovery of EEG activity in cat brains resuscitated with warm blood after frozen storage at -20°C (-4°F) for up to seven years.Reversible experiments in which all electrical activity stops, and chemistry comes to a virtual halt, disprove the 19th-cen-tury belief that there is a ‘spark of life’ inside living things. Life is chemistry. When the chemistry of life is adequately preserved, so is life. When the chemical structure and orga-nization of a human mind is adequately preserved, so is the person.Suda’s frozen cat brains deteriorated with time. Brains thawed after five days showed EEG patterns almost identical to EEGs obtained before freezing. However brains thawed after seven years showed greatly slowed activity. At a temperature of -20°C, liquid water still exists in a concentrated solution between ice crystals. Chemical deterioration still slowly occurs in this cold liquid.Preserving the chemistry of life for unlimited periods of time requires cooling below -130°C (-200°F). [14] Below this temperature, any remaining unfrozen liquid between ice crys-tals undergoes a “glass transition”. Molecules become stuck to their neighbors with weak hydrogen bonds. Instead of wan-
