Aha! effects in a guessing Chinese logogriph task: An event-related potential study

In the present study, high-density event-related potentials (ERPs) were recorded to examine the electrophysiologic correlates of Aha! effects in a guessing Chinese logogriph task by using a two-stage model for learning-testing. Results showed that: Firstly Successful Guessing elicited a more negative ERP deflection (N350) than Recognition did in the time window from 300-350 ms after onset of the stimuli. A voltage map of the difference wave (Successful Guessing minus Recognition) showed strong activity at the front-central region. Dipole analysis localized the generator of the N350 in the vicinity of the posterior cingulate cortex (PCC) and the inferior frontal gyrus. Secondly, a greater late positive component (LPC) in Successful Guessing than Recognition was found between 600 and 700 ms post-stimulus. Dipole analysis localized the generator of LPC in the right parahippocampal gyrus.