Spatiotemporal cortical activation underlying dilemma decision-making: an event-related potential study

Event-related brain potentials (ERPs) were measured when 18 Chinese subjects performed a dilemma decision task. During this task, subjects were required to decide who to rescue when two relatives (FN-FN, e.g., father and mother) or two strangers (SN-SN: stranger A and stranger B) were buried in the debris after a great earthquake. All subjects had experienced the great Sichuan earthquake on May 12th, 2008 in Chengdu city, China. Scalp ERP analysis revealed that FN-FN elicited a much more positive deflection (P2) than did SN-SN, which might reflect stimulus evaluation and conflict detection in the initiation of decision-making. In addition, a greater positivity (P350-450) in FN-FN as compared to SN-SN was found between 350 and 450ms post-stimulus, after hearing aftershock information. Dipole source analysis of difference wave (FN-FN minus SN-SN) indicated that two generators of the P350-450, localized in the parahippocampal gyrus and the cuneus, might be involved in dilemma interference resolution processes.