A concealment-specific frontal negative slow wave is generated from the right prefrontal cortex in the Concealed Information Test.

Recent studies have shown that a memorized item in the Concealed Information Test elicits a frontal negative slow wave (500-1000 ms) of the event-related potential, the cortical source of which involves the right prefrontal cortex. To examine whether this negative slow wave reflects a process that is specific to concealment rather than a more general cognitive control process, we compared the event-related potentials of 24 participants in four conditions involving the presence or absence of memory and the intention to conceal. Results showed that right prefrontal activation during the frontal negative slow wave (estimated by Standardized Low Resolution Brain Electromagnetic Tomography) was only observed when participants attempted to conceal the memorized item, but not when they were motivated to reveal it or had no intention to conceal. These findings suggest that the right prefrontal cortex is involved in a concealment-specific process in the Concealed Information Test.