An important challenge in measuring both FRN and P300 responses to stimuli within a common feedback task is that these two ERP components overlap partially in time, complicating standard time-domain methods of response quantification. To better isolate these distinctive feedback-locked components, we employed time-frequency (TF) analysis, an emerging tool in the psychophysiological literature that provides for separation of ERP components that overlap in time but have differing spectral (frequency) characteristics. Prior work has shown that the FRN and P300 in fact operate at different frequencies, and that they can be separated using TF approaches. Specifically, the P300 is composed largely of activity in the delta (< 3 Hz) range (Ba ar-Eroglu, Ba ar, Demiralp, & Schürmann, 1992; Ba ar-Eroglu, Demiralp, Schürmann, & Ba ar, 2001; Bernat, Malone, Williams, Patrick, & Iacono, 2007; Demiralp, Ademoglu, Istefanopulos, Ba ar-Eroglu, & Ba ar, 2001; Gilmore, Malone, Bernat, & Iacono, 2009), whereas the FRN (like the ERN) is composed more predominantly of activity in the theta (4–7 Hz) range (Gehring & Willoughby, 2004). In the current study, a recently developed TF decomposition method (Bernat,
