Thomas R Verny writes:

I began exploring the concept of cellular memory – the idea that memory can be stored outside the brain, in all the body’s cells – after reading an article on Reuters headlined ‘Tiny Brain No Obstacle to French Civil Servant’ in 2007. It seems that a 44-year-old French man had gone to hospital complaining of a mild weakness in his left leg. Doctors learned that the patient ‘had a shunt inserted into his head to drain away hydrocephalus – water on the brain – as an infant. The shunt was removed when he was 14.’ When they scanned his brain, they found a huge fluid-filled chamber occupying most of the space in his skull, leaving little more than a thin sheet of actual brain tissue. The patient, a married father of two children, worked as a civil servant apparently leading a normal life, despite having a cranium filled with spinal fluid and very little brain tissue.

To my surprise, I unearthed in the medical literature an astonishing number of documented cases of adults who, as children, had parts of their brain removed to heal their persistent epilepsy. Following hemispherectomy – where half the brain can be removed to control seizures – most children showed not only an improvement in their intellectual capacity and sociability but also their apparent retention of memory, personality and sense of humour. Similarly, adults who have had hemispherectomies enjoyed excellent long-term seizure control and increased postoperative employability.

If people who lack a large part of their brain can function normally, or even relatively normally, then there must exist, I thought, some kind of back-up system that can kick in when the primary system crashes. I devoted the next six years to studying the medical and scientific literature searching for evidence to support my hunch.

We’ve long assumed that one of the fundamental functions of the brain is its ability to store memories, thus allowing animals, including humans, to alter behaviour in light of past experience. If the seat of all memory was truly the brain, then to ensure long-term stability of stored information, the brain cells and their circuits would need to remain stable, like the books on your bookshelf. If someone started to tear pages out from these books, not only would the books be seriously damaged but you would have lost forever these books’ contents.

Yet, animals such as the planaria that exhibit a remarkable capacity to quickly regrow new body parts, including their brains, confront us with a fascinating question: how can fixed memories persist when bodies and even brains do not? [Continue reading…]