<sod>Most polygraph researchers have focused more the exam's predictive value on a subject’s guilt.  However, there have been no empirical theories established to explain how a polygraph measures deception.  Recent research indicates that [[Functional magnetic resonance imaging|Functional Magnetic Resonance Imaging]] (fMRI) may benefit in explaining the psychological correlations of polygraph exams.  It could also explain which parts of the brain are active when subjects use artificial memories.{{clarify |date=October 2016 |reason=What is an artificial memory?}}<ref>{{cite journal | last1 = Bell | first1 = B. G. | last2 = Grubin | first2 = D. | year = 2010 | title = Functional magnetic resonance imaging may promote theoretical understanding of the polygraph test | url = | journal = Journal of Forensic Psychiatry and Psychology | volume = 21 | issue = 1| pages = 52–65 | doi=10.1080/14789940903220676}}</ref> Most brain activity occurs in both sides of the [[prefrontal cortex]], which is linked to response inhibition. This indicates that deception may involve inhibition of truthful responses.<ref>{{cite journal | last1 = Langleben | first1 = DD | last2 = Schroeder | first2 = L | last3 = Maldjian | first3 = JA | last4 = Gur | first4 = RC | last5 = McDonald | first5 = S | last6 = Ragland | first6 = JD | last7 = O'Brien | first7 = CP | last8 = Childress | first8 = AR | year = 2002 | title = Brain activity during simulated deception: an event-related functional magnetic resonance study | url = | journal = NeuroImage | volume = 15 | issue = 3| pages = 727–32 | doi = 10.1006/nimg.2001.1003 | pmid = 11848716 }}</ref>  Recalling artificial memories are known to activate the [[posterior cingulate cortex]].  However, fMRIs are limited by being expensive, immobile, and having inconsistent lying responses. Some researchers believe that [[mental chronometry|reaction time]] (RT) based tests may replace polygraphs in concealed information detection.  RT based tests differ from polygraphs in stimulus presentation duration, and can be conducted without physiological recording as subject response time is measured via computer.  However, researchers have found limitations to these tests as subjects voluntarily control their reaction time, deception can still occur within the response deadline, and the test itself lacks physiological recording.<ref>{{cite journal | last1 = Verschuere | first1 = B. | last2 = Crombez | first2 = G. | last3 = Degrootte | first3 = T. | last4 = Rosseel | first4 = Y. | year = 2010 | title = Detecting concealed information with reaction times: Validity and comparison with the polygraph | url = | journal = Applied Cognitive Psychology | volume = 24 | issue = 7| pages = 991–100 | doi=10.1002/acp.1601}}</ref><eod>
<sod>Most polygraph researchers have focused more the exam's predictive value on a subject’s guilt.  However, there have been no empirical theories established to explain how a polygraph measures deception.  Recent research indicates that [[Functional magnetic resonance imaging|Functional Magnetic Resonance Imaging]] (fMRI) may benefit in explaining the psychological correlations of polygraph exams.  It could also explain which parts of the brain are active when subjects use artificial memories.{{clarify |date=October 2016 |reason=What is an artificial memory?}}<ref>{{cite journal | last1 = Bell | first1 = B. G. | last2 = Grubin | first2 = D. | year = 2010 | title = Functional magnetic resonance imaging may promote theoretical understanding of the polygraph test | url = | journal = Journal of Forensic Psychiatry and Psychology | volume = 21 | issue = 1| pages = 52–65 | doi=10.1080/14789940903220676}}</ref> Most brain activity occurs in both sides of the [[prefrontal cortex]], which is linked to response inhibition. This indicates that deception may involve inhibition of truthful responses.<ref>{{cite journal | last1 = Langleben | first1 = DD | last2 = Schroeder | first2 = L | last3 = Maldjian | first3 = JA | last4 = Gur | first4 = RC | last5 = McDonald | first5 = S | last6 = Ragland | first6 = JD | last7 = O'Brien | first7 = CP | last8 = Childress | first8 = AR | year = 2002 | title = Brain activity during simulated deception: an event-related functional magnetic resonance study | url = | journal = NeuroImage | volume = 15 | issue = 3| pages = 727–32 | doi = 10.1006/nimg.2001.1003 | pmid = 11848716 }}</ref>  Recalling artificial memories{{clarify |date=October 2016 |reason=What is an artificial memory?}} are known to activate the [[posterior cingulate cortex]].  However, fMRIs are limited by being expensive, immobile, and having inconsistent lying responses. Some researchers believe that [[mental chronometry|reaction time]] (RT) based tests may replace polygraphs in concealed information detection.  RT based tests differ from polygraphs in stimulus presentation duration, and can be conducted without physiological recording as subject response time is measured via computer.  However, researchers have found limitations to these tests as subjects voluntarily control their reaction time, deception can still occur within the response deadline, and the test itself lacks physiological recording.<ref>{{cite journal | last1 = Verschuere | first1 = B. | last2 = Crombez | first2 = G. | last3 = Degrootte | first3 = T. | last4 = Rosseel | first4 = Y. | year = 2010 | title = Detecting concealed information with reaction times: Validity and comparison with the polygraph | url = | journal = Applied Cognitive Psychology | volume = 24 | issue = 7| pages = 991–100 | doi=10.1002/acp.1601}}</ref><eod>