Frontal Theta Band Oscillations Predict Error Correction and Posterror Slowing in Typing
Performance errors are associated with robust behavioral and electroencephalography (EEG) effects. However, there is a debate about the nature of the relationship between these effects and implicit versus explicit error awareness. Our aim was to study the relationship between error related electrophysiological effects, such as spectral perturbations in fronto-medial theta band oscillations (FMT), and error awareness in typing. Typing has an advantage as an experimental paradigm in that detected errors are quickly and habitually signaled by the participant using backspace, allowing separation of detected from undetected errors without interruption in behavior. Typing is thought to be controlled hierarchically via inner and outer loops, which rely on different sources for error detection. Touch-typist participants were asked to copy-type 100 sentences as EEG was recorded in the absence of visual feedback. Continuous EEG data were analyzed using independent component analysis (ICA). Time-frequency and ERP analyses were applied to emergent independent components. The results show that single-trial FMT parameters and error related negativity (ERN) amplitude predict overt, adaptive posterror actions such as error correction via backspace; and, posterror slowing, reflecting implicit error awareness. In addition, we found that those uncorrected errors which were slowed down the most were also the ones associated with a high level of FMT activity. Our results as a whole show that FMT are related to neural mechanisms involved in explicit awareness of errors, and input from inner loop is sufficient for error correction in typing.