If fMRI Had Been Invented 100 Years Earlier


The seventh science advent prompt is asking to engage in a bit of speculation and imagine how our field would have looked like, should a discovery or invention entered the game 100 years earlier. The obvious choice for us is the poster child of neuroimaging, functional magnetic resonance imaging or fMRI, in brief.

fMRI is a method introduced in the 1990s, that has gained rapid popularity in the field of neuroscience. It was developed based on the assumption that, the more active a brain region is, the more blood will flow into it. In this context, the different magnetic properties of oxygenated versus deoxygenated blood can be used to determine which regions have an increased blood flow compared to others during certain tasks. But while this technique is widely used to study “brain activity” and to infer what regions might be important for what tasks, it lacks neither caveats, nor criticism.

One important point is that fMRI does not directly measure brain activity. As we’ve just mentioned, the blood-oxygen-level dependent (BOLD) signal is just a proxy for underlying neuronal activity. And while it has been empirically shown that there is a positive correlation between the two, the changes in blood flow happen on a much longer time scale compared to the fast dynamics of neuronal responses (seconds compared to miliseconds), so at best fMRI gives us a very blurry picture of what’s actually going on in the brain.

But an even worse point of criticism is how most task-based fMRI studies are used to claim that certain regions are responsible for specific behaviours. Up to a certain point, functional localization makes sense. This is particularly true for general functions: for example, there is a region involved (mostly) in visual processing, another one in auditory processing, a third one responsible for higher-order cognitive integration, and so on. Yet some researchers tend to use fMRI to go beyond that and seem determined to assign any behaviour, no matter how complex, its small portion of the brain. The problem? The same region appears to be activated in a wide variety of tasks. For example, the anterior cingulate cortex is involved in reward, decision-making, attention, emotion, and impulse control. So it might show activation both in a task that requires you to choose between two types of candy, as well as one that asks you to press a button when you see a happy face. That doesn’t mean the anterior cingulate cortex is responsible for candy preference or happiness recognition.

Alright, so what does this have to do with our prompt though? Well, despite the criticism from above, fMRI was a revolutionary method that suddenly allowed researchers a glimpse into the brain, that it shaped much of modern neuroscience, and that it remains one of the most widely used neuroimaging tools. Now, had this method been introduced in the 1890s instead, it would be tempting to say that our understanding of the brain would be much more advanced today. But we have to take into account that fMRI does not exist in a vacuum. Instead, analyzing fMRI data means relying on powerful computers and sophisticated software that would not have been available back then. So at best, it would have probably had a moderate impact.

Assuming, however, for the sake of argument, that this would not have been a limitation, it’s likely fMRI could have taken neuroscience on a darker path. You see, in the beginning of the 19th century, phrenology was all the rage. Now considered pseudoscience, phrenology used bumps on the skull to predict various mental traits (does it remind you of something?). As it was fashionable at the time, this was used to affirm racist claims and promote gender stereotyping, as well as to predict educational performance and criminal tendencies. Luckily, people figured out at some point that bumps on the skull don’t have anything to do with mental capacities, and by the end of the century, phrenology had mostly been discredited.

Coming at a time when proper scientific procedures were still being defined and given how easy it is to get fMRI data to confess to whatever regions one wants even with those procedures in place, it’s then quite easy to speculate that fMRI could’ve been exactly what phrenology needed to pivot and continue on its problematic path. And while, at the time, it was somewhat manageable to prove that skull bumps are not related to the brain, had illusory race and gender differences (which we know nowadays are not there) been “found” using a method that looks directly at the brain, it would’ve a lot more difficult to break out of this framework.

But that’s just our opinion and as we’ve already stated in the very beginning, it’s just speculation (hence also why no references at the end this time). What do you think? Would we have had a brighter future had fMRI been invented 100 years ago?

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