Neuroplasticity is a correction masquerading as a discovery. The error that it corrected was that for most of the 19th and 20th centuries, neuroscience operated under the assumption that the adult brain was a finished product.
1906 Nobel laureate Santiago Ramón y Cajal declared what became one of neurology’s central tenets: “In adult centers the nerve paths are something fixed, ended, immutable. Everything may die, nothing may be regenerated.” This decree was repeated in textbooks, taught in medical schools, and practiced by neurologists for the better part of a century. Until the 1990s, clinicians treating brain damage operated under Cajal’s assumption that whatever was lost was gone permanently — that the adult brain, unlike bone or muscle, could not reorganize or grow back. The brain you had at twenty-five was the brain you would die with. Period.
This, it turns out, was categorically wrong. Research from the 1960s onward demonstrates that the adult brain remodels itself continuously in response to experiences: synaptic connections strengthen or weaken based on patterns of activation, dendritic structures expand or contract, and in specific regions — the hippocampus in particular — new neurons generate throughout life. This is a genuine scientific correction of a genuine scientific error, and it matters enormously for how clinicians approach patients suffering from strokes, addiction, depression, and many other traumas and disorders.
But let’s take a look at another word that has attached itself to this discovery: “wiring” or “rewiring.” There are no wires in the brain. Neurons are not cables and the brain is not a circuit board. What actually changes are electrochemical thresholds, synaptic efficiencies, and the density of receptor proteins where the cells meet. “Rewiring” is an engineering metaphor imported into biology and “Neurons that fire together wire together” is a bumper sticker, not a scientifically accurate description. “Wires” are a metaphor that replaces complex, poorly understood electrochemical processes with reassuring visuals of a machine that can be upgraded and optimized. OK, forgive my rant on “wires” but nobody is doing science any favors by using inaccurate metaphors.
Similarly, the word “neuroplasticity” migrated from the laboratory to the bookshelf sometime in the early 2000s and its meaning changed almost entirely. In the laboratory it named a specific set of measurable, localized synaptic mechanisms. In the self-help section and in yoga studios across the country it means putative empowerment. “I’m expanding my corpus callosum right now!” I heard one teacher claim as if she were a Broadway understudy finally getting her chance on stage.
And in therapy and coaching offices, neuroplasticity has become something more akin to a promissory note: the brain can change, therefore you can change, therefore the program, app, latest and greatest therapeutic modality, or Costa Rica or Bali retreat being sold to you will produce that change. The word does the work of three marketing campaigns: that change is possible (true), that a particular intervention causes a specific change (scientifically unverifiable), and that the change produced is the change you requested (maybe, maybe not).
Which brings us to the real problem: as it is almost universally invoked outside the laboratory, at the individual level neuroplasticity is unverifiable. To attribute causality from an outside phenomenon to changes in a cluster of neurons in someone’s brain is science fiction. Whether or not my meditation practice has genuinely altered the thickness of my prefrontal cortex is impossible to determine. I would need to be inside an fMRI machine before and after the intervention, with my scans read by someone competent to distinguish neural reorganization from other changes, and all other variables would have to be held constant. And even then, establishing direct causality between say meditation and any observed change would present a methodological problem that most neuroimaging studies have not solved… fMRIs display correlations not causality, sample sizes are too small, there’s practically never a control group, effect sizes are often negligible, and replication is spotty at best.
Nobody I have ever heard utter the word “neuroplasticity” in public owns an fMRI machine. Nobody has a pre and post-intervention scan… I have truly heard better scientific arguments for leeching.
OK, so the brain is dynamic and continuously changing in response to experience. That claim is accurate — to the best of our current knowledge — but doesn’t that then make the word “neuroplasticity” redundant? We do not need a special word for a dynamic brain any more than we need a special word for wet water. The word only works if we are still implicitly contrasting it with the static brain Cajal decreed — that finished, immutable, fixed-and-ended structure that turned out not to exist.
“Neuroplasticity” is a word based on an error that it was coined to correct. The error has been corrected, but the word remains. Try walking around for a week replacing the word “earth” with “round earth” and remark if people look at you oddly.
That’s how we should regard the word “neuroplasticity” — as a word that is based on an error.
And if you’re a wellness professional (that term makes my skin crawl due to all of the hypocritical, undereducated yoga teachers and phony “spiritual coaches”) if that doesn’t disabuse you of ever uttering that word again, maybe this ditty by Nassim Taleb will: “Studying neurobiology to understand humans is like studying ink to understand literature.”
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Previously Published on Medium
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