Inferring behavior from functional brain images

Most neuroimaging experiments aim to identify brain areas whose activation correlates tightly with an aspect of the subjects' behavioral task. If the logic of neuroimaging is correct, however, it should also be possible to reverse this sequence of operations. Once we understand the function of a given brain area or network of areas, it should be possible to use on-line activation measurements to infer what kind of task the subject was performing. As a first step in this direction, we report here that functional magnetic resonance images (fMRI) of motor cortex have sufficient signal-to-noise ratio to accurately predict the subject's manual behavior on a single-trial basis with close to 100% accuracy.