FUNCTIONAL MRI |
Functional MRI (fMRI) is used to understand how different parts of the brain respond to external stimuli or passive activity in a resting state. Blood oxygenation level dependent (BOLD) fMRI measures the hemodynamic response to transient neural activity resulting from a change in the ratio of oxyhemoglobin and deoxyhemoglobin. Researchers use statistical methods to construct a 3D parametric map of the brain which indicates the regions of the cortex that demonstrate a significant change in activity in response to the task. fMRI has applications in behavioral and cognitive research, and in planning neurosurgery of eloquent brain areas.
fMRI as Lie Detector?
Some studies have already found an ability to detect deception using fMRI to be in the correct rate of 95-99%, and under specific, laboratory controlled conditions, fMRI was able to distinguish lies from the truth in individual subjects with 76% to 90% accuracy.
However, courts have also pointed out that the motivation to lie may be different in research v. real-world settings. In a laboratory experiment, one can assume that the participant is complying with investigator directions. However, if the scan is to be used in the courtroom, the subject will have a personal interest in the outcome, and may try to employ counter measures, or disregard instructions, in order to “fool” the scanner. Recent research shows that this task may not be hard, at least not for those who know how to effectively “trick” the scanner.
However, courts have also pointed out that the motivation to lie may be different in research v. real-world settings. In a laboratory experiment, one can assume that the participant is complying with investigator directions. However, if the scan is to be used in the courtroom, the subject will have a personal interest in the outcome, and may try to employ counter measures, or disregard instructions, in order to “fool” the scanner. Recent research shows that this task may not be hard, at least not for those who know how to effectively “trick” the scanner.