 Since at least the time of Ramon y Cajal (1852-1934), psychologists have speculated that the brain stores memory by altering the strength of connections between neurons that are simultaneously active.This idea was formalized by Donald Hebb in 1949, but for many years remained unexplained.In 1973, Tim Bliss and Terje Lømo described a phenomenon in the rabbit hippocampus that appeared to meet Hebb's specifications