A study out of Duke threatens to throw into chaos the last decade or more of fMRI studies that correlate consciousness with brain activity.
Hundreds of published studies over the last decade have claimed it’s possible to predict an individual’s patterns of thoughts and feelings by scanning their brain in an MRI machine as they perform some mental tasks.
But a new analysis by some of the researchers who have done the most work in this area finds that those measurements are highly suspect when it comes to drawing conclusions about any individual person’s brain.
They also examined data from the brain-scanning Human Connectome Project — “Our field’s Bible at the moment,” Hariri called it — and looked at test/retest results for 45 individuals. For six out of seven measures of brain function, the correlation between tests taken about four months apart with the same person was weak. The seventh measure studied, language processing, was only a fair correlation, not good or excellent.
Finally they looked at data they collected through the Dunedin Multidisciplinary Health and Development Study in New Zealand, in which 20 individuals were put through task-based fMRI twice, two or three months apart. Again, they found poor correlation from one test to the next in an individual.
McFadden made eight predictions for his cemi theory of consciousness. Prediction number 8 was:
The last prediction of the cemi theory — that consciousness should demonstrate field-level dynamics — is perhaps the most interesting, but also the most difficult to approach experimentally. In principle it should be possible to distinguish a wave-mechanical (em field) model of consciousness from a digital (neuronal) model. Although neurons and the fields generated by neurons hold the same information, the form of that information is not equivalent. For instance, although a complete description of neuron firing patterns would completely specify the associated field, the reverse is not true: a particular configuration of the brain’s em field could not be used to ‘reverse engineer’ the neuron firing patterns that generated that field. This is because any complex wave may be ‘decomposed’ into a superposition of many different component waves: a particular field configuration (state of consciousness) may be the product of many distinct neuron-firing patterns.
The Duke study is suggestive that McFadden’s prediction may be confirmed and that brain mapping projects associating particular circuits with specific states of consciousness or activities may be somewhat misguided.