Everyone who has ever looked at a pretty fMRI scan or read a popular science article linking some sexy human behavior to a blob on a pretty brain scan (so, “nearly everyone”) needs to read this blog entry at The New Yorker:
…a lot of those reports are based on a false premise: that neural tissue that lights up most in the brain is the only tissue involved in some cognitive function. The brain, though, rarely works that way. Most of the interesting things that the brain does involve many different pieces of tissue working together. Saying that emotion is in the amygdala, or that decision-making is the prefrontal cortex, is at best a shorthand, and a misleading one at that. Different emotions, for example, rely on different combinations of neural substrates. The act of comprehending a sentence likely involves Broca’s area (the language-related spot on the left side of the brain that they may have told you about in college), but it also draws on the parts of the brain in the temporal lobe that analyze acoustic signals, and part of sensorimotor cortex and the basal ganglia become active as well. (In congenitally blind people, some of the visual cortex also plays a role.) It’s not one spot, it’s many, some of which may be less active but still vital, and what really matters is how vast networks of neural tissue work together.
Don’t lose faith. Techniques like fMRI have unlocked some amazing science about the workings of the brain, but they are still pretty low-resolution, and can only take snapshots. What about the actions of individual neurons that fMRI can’t see? What if some processes are explained better using dynamic observations instead of snapshots, like video instead of photos?
Considering that dead salmon can show brain activity on fMRI, we need to be pretty careful when saying that “Blob X” is linked to “Condition Y”. It doesn’t say that everything you’ve heard is false, just that…
…simple explanations of complex brain functions that often make for good headlines rarely turn out to be true. But that doesn’t mean that there aren’t explanations to be had, it just means that evolution didn’t evolve our brains to be easily understood.
Considering it’s the most advanced biological computer ever created, that shouldn’t surprise anyone, right?
(via The New Yorker)