Spatiotemporal cortical activation underlies mental preparation for successful riddle solving: an event-related potential study.

Recently, Kounios J, Frymiare JL, Bowden EM, Fleck JI, Subramaniam K, Parrish TB et al. (2006) found that the mental preparation leading to insight involves heightened activity in medial frontal areas and temporal areas. In the present study, the electrophysiological correlates of successful and unsuccessful Chinese logogriph solving (riddles in which writing characters undergo several changes brought about by the addition, subtraction, omission or substitution of strokes or components of the characters) were studied in 18 healthy subjects using high-density event-related potentials (ERPs). Results show that the mental preparation for successful logogriphs elicited a more positive ERP deflection than unsuccessful logogriphs from -1,000 to -800 ms before onset of the target logogriphs. Dipole analysis localized the generators of the positive component primarily in the anterior cingulate cortex (ACC). This result is consistent with Kounios' view that general mental preparatory mechanisms modulate problem-solving strategy.