Event-related brain potentials during the standard autonomic-based concealed information test.

The concealed information test (CIT) has been used to detect information that examinees possess by means of their autonomic responses. However, the central activities related to these autonomic responses remain unclear. In this study, we simultaneously recorded 128-ch event-related potentials (ERPs) and various autonomic responses (heart rate, respiratory rate, respiratory amplitude, cutaneous blood flow, and skin conductance response) to a critical item (i.e., the item that participants memorized) and to non-critical items (i.e., items other than the critical item) using the standard protocol of the autonomic-based CIT. A topographic analysis of variance and a temporal-spatial principal component analysis revealed that the critical item elicited a larger negative potential (N2b, 205-298 ms) at central regions and a larger positive potential (positive slow wave, 502-744 ms) at parieto-occipital regions, compared to the non-critical items. Correlation analysis across 21 participants showed a significant correlation between N2b increase and heart rate deceleration in response to critical items compared to non-critical items, but there were no autonomic correlates of the positive slow wave. The results suggest that at least two brain processes are involved in the autonomic-based CIT: The first is an attentional-orienting process that facilitates the processing of critical items, to which heart rate deceleration was linked, and the second is an additional process after the identification of critical items.