Determining innocence of a criminal charge based upon interrogation and evidence can be a difficult and indeterminate process. Polygraphy is limited by reliance on peripheral manifestations of anxiety (skin conductance, heart rate, and respiration), which can to certain extents be circumvented. Scalp-recorded event-related potentials (ERPs) reflect neuronal activity associated with a sensory, motor, or cognitive event. The P-300 wave of the ERP appears in response to rare, meaningful stimuli, and its amplitude and latency has been associated with deception (lying on the Guilty Knowledge Test, GKT). This suggests that the cognitive differences between lying and telling the truth could be associated with changes in other correlates of brain activity, such as regional cerebral blood flow Unfortunately, the ESP provides high temporal but no spatial resolution in the brain.
Since deception-induced mood and somatic states may vary across individuals, a marker of deception independent of anxiety or guilt is important. Regional brain activity, manifest as a blood oxygenation level dependent (BOLD) response. elicited by inhibition of the truth response during intentional deception has been demonstrated to serve as such a marker. Unlike the ERP, the spatial resolution of BOLD event-related (questioning) functional MRI neuroimaging is sufficient to anatomically localize changes in cerebral blood flow related to regional neuronal activity during cognition.
A number of publications in peer-reviewed medical journals have used MRI to identify deceptive and truthful responses. Deceptive responses were associated with increased activity in specific areas of the brain. These results indicate that cognitive differences between deception and truth have neural correlates that can be detected by fMRI.
fMRI has shown that suppression of a particular thought, when compared to free-thought control condition, revealed greater activation in certain specific areas of the brain. fMRI can distinguish the suppression of all conscious thoughts compared to free-thought. fMRI can also distinguish truth and false visual recognition. The sensory signal distinguishing truth from deception may not be accessible to conscious awareness, indicating that intentional deception can be identified.
MMT NeuroTech uses specifically developed imaging and analysis algorithms and customized interrogation protocols to fit the individual situation. MMT NeuroTech can apply these techniques for forensic purposes to individual circumstances.