Merzenich, meanwhile, helped to confirm in the late 1960s that the brain contains ‘maps’ of the body and the outside world, and that these maps have the ability to change. Next, he co-developed the cochlear implant, which helped deaf people hear. This relies on the principle of plasticity, as the brain needs to adapt to receive auditory information from the artificial implant instead of the cochlea (which, in the deaf person, isn’t working). In 1996 he helped establish a commercial company that produces educational software products called Fast ForWord for “enhancing the cognitive skills of children using repetitive exercises that rely on plasticity to improve brain function,” according to their website. As Doidge writes, “In some cases, people who have had a lifetime of cognitive difficulties get better after only 30 to 60 hours of treatment.”

Although it took several decades, Merzenich and Bach-y-Rita were to help prove that Cajal and the scientific consensus were wrong. The adult brain was plastic. It could rewire itself, sometimes radically. This came as a surprise to experts like Robertson, now a Director of Trinity College Dublin’s Institute of Neuroscience. “I can look back on giving lectures at Edinburgh University to students where I gave wrong information, based on the dogma which said that, once dead, a brain cell cannot regenerate and plasticity happens in early childhood but not later,” he says.

Rewired brains

It wasn’t until the publication of a series of vivid studies involving brain scans that this new truth began to be encoded into the synapses of the masses. In 1995, neuropsychologist Thomas Elbert published his work on string players that showed the ‘maps’ in their brain that represented each finger of the left hand – which they used for fingering – were enlarged compared to those of non-musicians (and compared to their own right hands, not involved in fingering). This demonstrated their brains had rewired themselves as a result of their many, many, many hours of practice.

Three years later, a Swedish-American team, led by Peter Eriksson of Sahlgrenska University Hospital, published a study in Nature that showed, for the very first time, that neurogenesis – the creation of new brain cells – was possible in adults. In 2006, a team led by Eleanor Maguire at the Institute of Neurology at University College London found that the city’s taxi drivers have more grey matter in one hippocampal area than bus drivers, due to their incredible spatial knowledge of London’s maze of streets. In 2007, Doidge’s The Brain that Changes Itself was published. In its review of the book, the New York Times proclaimed that “the power of positive thinking has finally gained scientific credibility”. It went on to sell more than one million copies in more than 100 countries. Suddenly, neuroplasticity was everywhere.