12 March 2012

The (current) limits of neuroimaging

I confess that I’m one of those neuroscience buffs who overestimate the advances made in this field of study. Rejecting dualism comes with a hazard: you tend to idealise any technology that can potentially prove once and for all that the mind is entirely created by the brain. But my idealism has been tempered with a healthy dose of realism after reading this article - it describes the limits of current neuroscience technology like functional magnetic resonance imaging (fMRI) and shows the dangers of overselling the usefulness of neuroimaging. Conversely, it also touches on the danger of ignoring the contributions of neuroimaging, particularly in disciplines like psychiatry. This paragraph makes it quite clear that psychiatry needs to do some serious house cleaning if it is to remain a credible science.

Neuroimaging research also could completely change how we think about psychiatric disorders by rendering obsolete the idea that using discrete diagnostic categories such as schizophrenia or attention-deficit/hyperactivity disorder (ADHD) provides the best way to understand the underlying disorders. Today, these diagnoses are based on formal criteria, outlined in the American Psychiatric Association’s Diagnostic and Statistical Manual, that specify symptoms for each disorder. But these criteria have no basis in neuroscience. In fact, the psychiatric community has become increasingly concerned that traditional diagnostic categories actually obscure the underlying brain systems and genes that lead to mental health problems. In addition, a growing body of evidence indicates that many psychiatric problems lie on a continuum rather than being discrete disorders, in the same way that hypertension reflects the extreme end of a continuum of blood pressure measurements. Neuroimaging provides us the means to go beyond diagnostic categories to better understand how brain activity relates to psychological dysfunction, whereas using it to “diagnose” classical psychiatric disorders could obscure, rather than illuminate, the true problems.

I’m still a staunch materialist, and all this new information doesn’t suggest that dualism is a valid idea. What it does suggest is that although the field of neuroscience is discovering more and more about how the brain gives rise to consciousness, we shouldn’t attribute discoveries to it that it hasn’t actually made.

HT: Matt O Bee


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