The new enthusiasm for neuroplasticity

Research has already demonstrated that adult neurogenesis occurs in specific areas of the brain. I wouldn't be surprised if neurogenesis occurs throughout the whole brain, in response to proper stimulus. I suspect that the reason it doesn't generally occur is that it is more efficient to grow new synapses between existing neurons than to differentiate stem cells into new neurons.

By analogy, muscles can undergo a fairly good amount of hypertrophy just via protein synthesis of contractile elements. However, in response to severe stress/trauma, satellite cells (a form of quiescent, partially differentiated stem cell) merge with muscle cells; the result of this is a muscle cell with a greater potential for hypertrophy.

Perhaps neurogenesis and only occurs under special conditions (like muscular myonuclear addition), such as extremely novel stimulus, or great mental effort. This would make it extremely difficult to induce experimentally.

Overall, an excellent and very balanced article, especially the care taken to address what neuroplasticity really means, and what it doesn't, as well as the current state of research.

The conflation of "personal-transformation" as a "myth" with the myths associated with neuroplasticity is unfortunate though:

> [Chris McManus, Professor of Psychology and Medical Education at University College London] believes it is just the latest version of the personal-transformation myth that’s been haunting the culture of the West for generations.

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> This myth – that we can be whoever we want to be, and achieve our dreams, as long as we have sufficient self-belief – emerges again and again, in our novels, films and news, and TV singing competitions featuring Simon Cowell, as well as unexpected crazes like that for neuroplasticity.

"Haunting"? Possibly, the author has some derision considering his "great-great-uncle" is "the inventor of the ’self-help’ movement". Regardless, it felt like a rather unscientific ax to grind.

FWIW, the author points out that neuroplasticity myths are used to justify some undesirable conclusions, though he stops short of providing examples or references.

Kind of sad to see the author take such a derogatory outlook on some of these self-help approaches. These sorts of things do appear periodically but they do not promise neuroplasticity as a quick cure-all as the author says they do. What's great about thinking of neuroplasticity as a sort of self-help is that it by definition takes a great deal of work to "rewire" any part of the brain. Neuroplasticity is the promise of improvement using hard work, so I suppose I'm upset with the authors standpoint.

It amazes me how much we already discovered about our brains, yet how little do we really know about it and how much more is to know. From a CS point of view it is also very exciting how current hot areas, like machine learning are closing on on the same questions from a different angle. Are we digital or analog? Is our self simply a reflection of an incredibly deep, recursive, emergent meta-structure or is there some ineffable underlying level? Or both or neither? :) Exciting times we live in...

>"For many years, the consensus was that the human brain couldn’t generate new cells once it reached adulthood. Once you were grown, you entered a state of neural decline. This was a view perhaps most famously expressed by the so-called founder of modern neuroscience Santiago Ramon y Cajal. After an early interest in plasticity, he became sceptical, writing in 1928, “In adult centres the nerve paths are something fixed, ended, immutable. Everything may die, nothing may be regenerated. It is for the science of the future to change, if possible, this harsh decree.” Cajal’s gloomy prognosis was to rumble through the 20th Century."

Can anyone point out what evidence is cited that conflicts with Cajal's claim? I don't see it. They mention functional reorganization (a change in the weights between neuronal connections as opposed to structure), but don't address why this is an inadequate explanation:

"Neuroplasticity can refer to structural changes, such as when neurons are created or die off or when synaptic connections are created, strengthened or pruned. It can also refer to functional reorganisations, such as those experienced by the blind patients of Paul Bach-y-Rita, whose contraptions triggered their brains to start using their visual cortices."