On Neuroscience, Journalism, and Truth

I mentioned this article last week on my new Twitter feed, but I feel it is good enough that it deserves a full post.  It’s a piece from NPR online that delves fairly deeply into the various issues that complicate and potentially cloud the interpretation of neuroscience research that uses fMRI.  To anyone engaged in that research on a daily basis, there will be little new to discover by reading it, but I suspect that non-scientists will learn much about just how much we can, and often do, get wrong with neuroimaging.  In fact, the breadth of the gap between those two experiences is sort of the point itself, as even intelligent and engaged lay consumers of popular neuroscience writing are rarely exposed to the many caveats that should accompany most findings.

Of course, the problem of sensationalism and technical illiteracy is endemic to science writing (and I would strongly recommend this Bloggingheads diavlog from the past weekend that discusses the depressing state of scientific understanding and science journalism).  But neuroscience research undeniably draws a special degree of attention–we’re of course fascinated with understanding ourselves, and the technological glitz of fMRI seemingly promises the ultimate means of accomplishing that–and so it likewise carries a greater responsibility to communicate the facts fully and accurately.

One ubiquitous fault in the popular discussion of neuroscience, which even the NPR piece stands guilty of, is the use of the phrase “lights up” to describe what putatively involved brain regions are doing during some activity.  I hate this phrase, and I wish it could be forever expunged from the vocabulary of science writers.  I’d be extremely interested to hear where this idiom was invented, but it’s not hard to see why it’s so common: the pretty “spot on brain” pictures appear to capture neural tissue flashing like a beacon.  In reality, though, those figures are just a way of communicating the result of a statistical test comparing activity between two conditions.

If we’re right about fMRI, of course, a well-designed experiment will lead to one or several brain regions doing something interesting, and they might even experience more activity, as the “lights up” trope implies.  The problem with the image, though, is that there is electrical activity going on all over your brain at all times.  And fMRI does not even measure this activity, it measures blood flow.  From increased neural firing to a rush of oxygenated blood, out through the magnet to a computer, transformed by a half-dozen measures of pre-processing and than statistical analysis, the steps between brain activity and finalized neuroimaging data are many and large.  Talking about brain activity as “lighting up” and implying that the pretty pictures accompanying your article show this happening only serves to reinforce a misleading perception of how the science works.  It’s easy to understand why science journalists lean so heavily on that phrase.  Talking about what’s really going on in a way that isn’t confusing or boring–or probably both–is really quite difficult.  It’s snappy and concise to say that “your fusiform face area lights up when you look at a face.”  On the other hand, “compared to baseline or the viewing of inanimate objects, viewing a face stimulus is associated with increased BOLD (blood oxygen level dependent) signal in voxels centered around the putative fusifrom face area on the ventral temporal lobe” is liable to make any copy editor cringe.  And even that explanation elides all of the various decisions made in the processing of the data that play a causal role in the discovery of scientific conclusions.

Don’t get me wrong: I believe fMRI holds great potential.  Already, the young field is starting to move past relatively simple “spot on brain” type experimental designs to sophisticated pattern classification, functional connectivity analyses, multimodal imaging with DTI (diffusion tensor imaging–a method that determines the extent of structural connectivity between different regions) and other cutting edge techniques that show significant promise in expanding what we can do with a brain scanner.  And we’re likely going to learn that many of our early theories were wrong, perhaps to the degree where they seem foolish.  Remember how physicists used to be convinced that we all existed in the ether?

Ultimately, I’m sure that neuroscience is the means to unlock all of the deep secrets about our nature.  But there are a whole host of reasons we should be wary of getting ahead of ourselves.  Ill-gotten scientific “conclusions” have, in the past, been extorted to nefarious ends, and there is not insignificant potential of the same with brain research.  Too much sensationalism also runs the risk of a disillusioned public, who will give the field up for quackery long before we get to the real answers.  But perhaps most importantly, science is fundamentally about the pursuit of truth.  Even without a risk of negative consequences, to ignore truth is to betray the very nature of science.  Without that, what’s the point?

Pretty brain image via http://prefrontal.org