Dorsolateral prefrontal cortex specifically processes general - but not personal - knowledge deception : multiple brain networks for lying

Despite intensive research into ways of detecting deception in legal, moral and clinical contexts, few experimental data are available on the neural substrate for the different types of lies. We used transcranial direct current stimulation (tDCS) to modulate dorsolateral prefrontal cortex (DLPFC) function and to assess its influence on various types of lies. Twenty healthy volunteers were tested before and after tDCS (anodal and sham). In each session the Guilty Knowledge Task and Visual Attention Task were administered at baseline and immediately after tDCS ended. A computer-controlled task was used to evaluate truthful responses and lie responses to questions referring to personal information and general knowledge. Dependent variables collected were reaction times (RTs) and accuracy. At baseline the RTs were significantly longer for lies than for truthful responses. After sham stimulation, lie responses remained unchanged (p = 0.24) but after anodal tDCS. RTs decreased significantly only for lies involving general knowledge (p = 0.02). tDCS left the Visual Attention Task unaffected. These findings show that manipulating DLPFC function with tDCS specifically modulates deceptive responses for general information leaving those on personal information unaffected. Multiple cortical networks intervene in deception involving general and personal knowledge. Deception referring to general and personal knowledge probably involves multiple cortical networks.