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by brainmapper
1759 days ago
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Please note that merely seeing some place in the brain activate in a functional MRI task does NOT necessarily mean that that location is either necessary, sufficient or even involved in representing information relevant to that task. Functional MRI amplifies small global signals related to arousal, and if arousal changes during a task then these arousal-related signals can propagate over much of the brain. And even something as simple as an eye movement can be correlated with global changes in arousal. (A similar problem occurs with attention.) Unfortunately many of the most common modeling and analysis methods methods used in fMRI have no way to distinguish these rather uninteresting arousal-related changes from those that are actually informative about task-specific processes. The bottom line is that whenever you read about any fMRI result, you should ask yourself whether that could be a mere artifact of changes in arousal (or attention), and if so you should find out what was done to address this potential confound. |
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