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Poster di Mameli F., Mrakic-Sposta S., Vergari M., Fumagalli M., Macis M., Ferrucci R., Barbieri S., Priori A. Presentato a Padova per il convegno "Neuroetica" 3-7/06/2010. Poster relativi a lavori sperimentali, teorici, analitici e critici riguardanti le applicazioni e le ricadute filosofiche, sociali, legali e politiche della ricerca neuroscientifica.
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1Mameli F., 1Mrakic-Sposta S., 1Vergari M., 2Fumagalli M., 1Macis M., 1Ferrucci R., 3Barbieri S., 1, 2, 3Priori A.1Centro Clinico per le Neuronanotecnologie e la Neurostimolazione, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico,
Milano, Italy2Dipartimento di Scienze Neurologiche, Università degli Studi di Milano, Milano, Italy
3U.O. Neurofisiologia, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico, Milano, Italy
THE LIAR BRAIN: EVIDENCE FOR MULTIPLE BRAIN NETWORKS FOR DECEPTION
INTRODUCTIONReliable ways of detecting deception have attracted growing interest for legal, moral and clinical purposes (Pavlidis et al., 2002; Vrij2006). Research on deception conducted over the past ten years has focused primarily on lie detection techniques intended tostudy deceptive processes in the brain. Functional magnetic resonance imaging (fMRI) studies show that the dorsolateral prefrontalcortex (DLPFC) are activated during lying (Langleben et al., 2005). Other studies used brain stimulation to investigate changes incortical excitability during deception (Priori et al., 2008; Karim et al., 2009). Despite several studies have indicated a predominantrole of the prefrontal cortex in deception, yet few experimental data are available on the neural substrate of different types of lies.
WE INVESTIGATED WHETHER DLPFC-tDCS CAN SPECIFICALLY INFLUENCE COGNITIVE PROCESSING OF GENERAL KNOWLEDGE DECEPTION OR ALSO INFLUENCE PROCESSING OF PERSONAL INFORMATION DECEPTION
METHODS
I Experimental Design
20 healthy volunteers were tested before and after tDCS (anodal and sham). All participants received anodal and sham(placebo) tDCS, tested during two separate experimental sessions held at least 1 week apart. The two types of stimulation werepresented in counterbalanced order across subjects, half of the participants received first anodal tDCS.
II TasksIn each session the Guilty Knowledge Task (GKT) and VisualAttention Task (VAT) were administered at baseline andimmediately after tDCS ended.
III Statistical Analysis
Guilty Knowledge TaskA computer-controlled task was used toevaluate truthful responses and lie responsesto questions referring to personal informationand general knowledge. Dependent variablescollected were reaction times (RTs) andaccuracy.
A repeated-measures analysis of variance (ANOVA) was run using Greenhouse-Geisser corrections for both tasks. Post hocanalysis with Tukey’s Honest Significant Difference (HSD) test was used to assess differences between the dependent variablesmeasured at baseline and after tDCS for each task.
CONCLUSIONSThese findings show that modulating DLPFC excitability with tDCS specifically modulate deceptive responses for generalinformation leaving those on personal information unaffected. These findings show that focal manipulation of brain function withtDCS specifically influences lie production and that distinctive neural mechanisms underlie different types of lies.
RESULTS
RESULTS
GENERAL KNOWLEDGE PERSONAL INFORMATION
Neither sham nor anodal tDCS induced significant changes in VAT RTs(F1,57 = 0.8, p = 0.37).After anodal DLPFC-tDCS repeated-measures ANOVA identifiedsignificant 2-way and 3-way interactions for RTs in the GKT (time×tDCS:F1,64 = 4.3, p = 0.04; time×tDCS×response type: F3,64 = 2.6, p = 0.05).Post hoc analysis confirmed that tDCS speeded up lies to generalknowledge (1244.5 ± 110.3 ms vs 1083.5 ± 97.2 ms; F2,64 = 2.8; p = 0.02).Conversely, tDCS failed to change the RTs for personal lies (1033.6 ± 64.3vs 1114.5 ± 91.7; p = 0.92).
REFERENCES-Pavlidis I, Eberhardt NL, Levine JA. Seeing through the face of deception. Nature, 2002;415:35.-Vrij A, Mann S, Fisher RP. An empirical test of the behaviour analysis interview. Law Hum Behav, 2006;30:329-345.-Langleben DD, Loughead JW, Bilker WB, Ruparel K, Childress AR, Busch SI, Gur RC. Telling truth from lie in individual subjects with fast event-related fMRI. Hum Brain Mapp, 2005;26:262-272.-Priori A, Mameli F, Cogiamanian F, Marceglia S, Tiriticco M, Mrakic-Sposta S, Ferrucci R, Zago S, Polezzi D, Sartori G. Lie-specific involvement of dorsolateral prefrontal cortex in deception. CerebCortex, 2008;18:451-455.-Karim AA, Schneider M, Lotze M, Veit R, Sauseng P, Braun C, Birbaumer N. The Truth about Lying: Inhibition of the Anterior Prefrontal Cortex Improves Deceptive Behavior. Cereb Cortex, 2009; 20(1):205-13.
