Cellular memory is the theory that biological cells other than nerve cells can store memories. Transplant patients sometimes seem to develop the personality characteristics of their deceased organ donors; this phenomenon led to the theory that humans possess cellular memory. Most scientific authorities disregard the theory, as no cellular structure capable of storing memories has been discovered. There has been some indication, however, that single-cell organisms have a function resembling memory. The idea of cellular memory is popular in fiction and film and has been particularly well represented in horror movies.
In advanced creatures such as humans, memory is a function of the brain, which is composed of millions of specialized nerve cells, or neurons. These cells interact through rapid chemical and electrical signals that maintain all brain functions, including memory. The actual process involved in memory is a subject of continuing study. Several major brain structures are involved, including the hippocampus, amygdala, and the basal ganglia. In some cases of brain damage affecting memory centers, the brain has been able to reroute around the damage and allow memory to continue to function.
Cellular memory is the idea that memories can be stored in other cells so that, for example, a heart transplant patient may take on memories or personality characteristics of the heart’s donor. Many people, including some medical professionals, believe this is possible. Skeptics, however, cite an absence of verifiable and repeatable experimental evidence. They suggest that stories seeming to prove cellular memory may be examples of the fallacy called confirmation bias. This is the natural tendency of people to pay attention to facts that support their beliefs while ignoring facts that dispute or disprove them.
Proponents of cellular memory often cite cases such as that of Claire Sylvia, who experienced strong personality changes after receiving a heart and lung transplant from a young male donor. Sylvia wrote a popular book that was later adapted into a 2002 television movie. In 2008, scientists in Japan discovered that a slime mold demonstrated behavior similar to memory when responding to stimuli. The slime mold is a simple organism that has no neurons or similar structures. This suggests that something like cellular memory is possible for such creatures, although it does not prove that humans have cellular memory.
Nevertheless, the concept has proved popular with filmmakers, particularly those in the horror genre. The classic example is The Hands of Orlac, a 1924 Austrian film about a pianist overcome by the urge to kill after receiving the transplanted hands of an executed murderer. The film inspired numerous similar movies, including Mad Love, an American remake starring Peter Lorre. Another popular concept involves characters experiencing terrifying visions after eye or cornea transplants, because their eyes “remember” horrifying things they saw in the past. This concept has been used in films such as the 2002 Korean horror film The Eye and its later American remake.