Chan, CCH

Feng, CM

Fox, PT

Gao, JH

Hou, JW

Lee, TMC

Liu, HL

Mahankali, S

Tan, LH

HKU Scholars Hub

Title Lie Detection using functional MRIAuthor(s) Liu, HL; Lee, TMC; Tan, LH; Chan, CCH; Feng, CM; Hou, JW;Mahankali, S; Fox, PT; Gao, JHCitationThe 9th Scientific Meeting and Exhibition of the InternationalSociety for Magnetic Resonance in Medicine (ISMRM 2001),Glasgow, UK., 23-27 April 2001.Issued Date 2001URL http://hdl.handle.net/10722/109841Rights This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.Proc. Intl. Soc. Mag. Reson. Med 9 (2001) 1295Proc. Intl. Soc. Mag. Reson. Med 9 (2001) 1295Lie Detection using Functional MRIHo-Ling Liu1, Tatia M.C. Lee2, Li Hai Tan3, Chetwyn C.H. Chan4, Ching-Mei Feng5, Jinwen Hou5, Srikanth Mahankali5,Peter T. Fox5, Jia-Hong Gao51Dept. of Medical Technology, Chang Gung Univ., Dept. of Diagnostic Radiology, Chang Gung Medical Center, Taoyuan, Taiwan; 2Dept. ofPsychology, Univ. of Hong Kong, ; 3Lab. for Language Neuroscience and Cognition, Dept. of Linguistics, Univ. of Hong Kong, ; 4Dept ofRehabilitation Sciences, The Hong Kong Polytechnic Univ., ; 5Research Imaging Center, Univ. of Texas Health Science Center, San Antonio,TX, ;IntroductionThe Digit Memory Test (DMT) of a forced choice format has beenpreviously documented to improve the accuracy of deception detection(1,2). Recently, it was demonstrated that simulated malingerers wereclearly distinguishable from normal controls using this method (3). Inthis study, we implemented DMT in a functional MRI (fMRI)experiment to examine the brain activation during simulatedmalingering. It is clearly evident that intentional lying requiresaccurate verbal recall followed by conscious manipulation of therecalled information and hence intimately involves neural substratesresponsible for such behavior. Most recently, other investigators haveshowed that prefrontal cortices were strongly activated duringinformation manipulation and integration, programming strategies, andthe control of executive functions (4, 5). Therefore, we hypothesizedthat lying would place a heavier demand on the prefrontal regions thansimple recall. FMRI was utilized to test this hypothesis by measuringbrain activation during both correct recall and intentional lying.MethodsTo investigate neural changes underlying deception, the cerebralactivity of 5 male volunteers was monitored using fMRI both duringaccurate verbal recall and when they faked a memory problem. Allparticipants (age range: 31.6 - 37.2 years) had academic qualificationsupto the level of postgraduation. The attention span of the subjectsduring the experiment was controlled at the 7 +/- 1 digit's level asmeasured by the Digit Span test. In order to encourage skillful lying,two other conditions, namely, answering incorrectly and answeringrandomly were added to the design. Following the DMT of a forcedchoice format, we performed this blocked design fMRI study using 3-digit numbers. Each block was initiated by the control condition (14sec), instruction (4 sec), and then followed by one of the fourexperimental conditions (28 sec). The control condition involved theviewing of a 3-digit number without the component of recall. The fourexperimental conditions included answering correctly, faking badly,answering incorrectly, and answering randomly. Two trials wereincluded in the control state, and four in the task state. During eachtrial, each number was exposed for 0.75 followed by visual fixation ona cross hair for 2.25 sec. Upon completion of this, a new number wasagain presented for 0.75 sec followed by a cross hair for 3.25 sec. Forthe task state, subjects were requested to respond, during the 3.25 secvisual fixation, according to the specific instructions set aside for eachexperimental condition. Three blocks were repeated for each of thefour conditions. The duration of each block was 46 seconds. Care wastaken to ensure that the order of the experimental conditions wasbalanced among the 12 blocks of scanning. After scanning wascompleted, all participants were asked about the strategies they hadadopted for faking badly during the experiment. Experiments wereperformed on a 1.9 T GE/Elscint Prestige MRI scanner. A T2*-weighted gradient-echo EPI sequence was used for fMRI scans, withthe slice thickness = 6 mm, in-plane resolution = 2.9 mm x 2.9 mm,and TR/TE/FA= 2000 ms/45 ms/900. Twenty axial slices wereacquired to cover the whole brain. For each slice, 276 images wereacquired with a total scan time of 552 s. For the anatomical detail, aT1-weighted image was obtained with the resolution of 1 mm3.Activation maps were calculated by comparing images acquired duringeach task state with those acquired during the control, and specially,during the faking badly with the answering correctly task states, usinga t-test. Images were spatially normalized to the Talairach space usinga Convex Hull algorithm (6). The averaged activation maps acrosssubjects with a t value threshold corresponding to p < 0.01 were thenoverlaid on the corresponding T1 images. For each comparison,Talairach coordinates of the center-of-mass and volume of theactivation clusters were determined based on the averaged activationmaps.ResultsIn the comparison between the faking badly and the answeringcorrectly task states, we observed a strong activation in the prefrontalregions bilaterally that was accompanied by significant activationinvolving both the fronto-polar prefrontal areas (BA 10)(Fig. 1a-1c).Significant activation was also seen bilaterally in the following areasof the brain: anugular (BA 39) and supramarginal (BA 40) gyri of theparietal lobe, and the cingulate and caudate locations of subcorticalregions. The activation of BA 39 & 40 was not unexpected because allparticipants reported that they had made calculated responses. It wasalso evident that the most popular strategy adopted in feigning amemory problem was to calculate the proportion of right and wronganswers. These findings are in excellent conformity and consistencywith previous knowledge that suggests the involvement of the fronto-parietal network in the comparison and computation of digits. Theinvolvement of the subcortical region in this group of subjects wasmost likely due to self-monitoring of random errors. We repeated theexperiment again but used instead autobiographic questions of a forcedchoice format. Similar loci were activated even in the repeatexperiment (Fig. 1d-1f).DiscussionOur findings provide conclusive evidence of the existence andinvolvement of a fronto-parietal-subcortical circuit in feigning amemory problem. Extensive examination of lying and deceptiondetection in both normal and clinical populations using behavioral andfunctional imaging paradigms will provide further theoreticalrefinement of these findings. Validations of our data will alsodefinitely help in establishing a platform for cross validation offunctional imaging and behavioral paradigms in the detection ofdeception. Potentially significant applications of this work includefuture investigations aimed at distinguishing different types of liarsand different types of lying with or without metacognitive calculations.Figure 1. Averaged functional maps (p < 0.01) overlaid on the T1images, in faking badly vs. answering correctly states using DMT(a-c) and autobiographic test (d-f). Three normalized planes are z= 36, 12 and 0 mm, relative to the bicommissural line.References1. Hall, H. V., & Pritchard D. A., Detecting Malingering andDeception: Forensic distortion analysis (FDA), 1996.2. Hiscock, C. K., et al., J Psychopath Beh Ass, 16, 95, 1994.3. Chiu, V. W. Y. & Lee, T. M. C. Law Human Behav (in press).4. Prabhakaran, V., et al., Nature Neuroscience, 3, 85, 2000.5. Shallice, T. Nature Neuroscience, 2, 588, 1999.6. Lancaster J.L., et al., J Nucl Med, 40, 942, 1999.

Lie Detection using functional MRI

Lie Detection using functional MRI

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