Binary sensitivity of theta activity for gain and loss when monitoring parametric prediction errors.

Several theories have been proposed to account for the medial frontal activity that is elicited during the evaluation of outcomes. Respectively, these theories claim that the medial frontal response reflects (i) the absolute deviation between the value of an outcome and its expected value (i.e. an absolute prediction error); (ii) the deviation between actual and expected outcomes, with a specific sensitivity to outcomes that are worse than expected (i.e. a negative prediction error); (iii) a binary evaluation in terms of good and bad outcomes. In the current electroencephalography study, participants were presented with cues that induced specific predictions for the values of trial outcomes (a gain or loss of points). The actual outcomes occasionally deviated from the predicted values, producing prediction errors with parametrically varying size. Analysis of the medial frontal theta activity in response to the outcomes demonstrated a specific sensitivity to the occurrence of a loss of points when a gain had been predicted. However, the absolute deviation with respect to the predicted value did not modulate the theta response. This finding is consistent with the idea that outcome monitoring activity measured over medial frontal cortex is sensitive to the binary distinction between good and bad outcomes.

Neural correlates of feedback processing in toddlers.

External feedback provides essential information for successful learning. Feedback is especially important for learning in early childhood, as toddlers strongly rely on external signals to determine the consequences of their actions. In adults, many electrophysiological studies have elucidated feedback processes using a neural marker called the feedback-related negativity (FRN). The neural generator of the FRN is assumed to be the ACC, located in medial frontal cortex. As frontal brain regions are the latest to mature during brain development, it is unclear when in early childhood a functional feedback system develops. Is feedback differentiated on a neural level in toddlers and in how far is neural feedback processing related to children's behavioral adjustment? In an EEG experiment, we addressed these questions by measuring the brain activity and behavioral performance of 2.5-year-old toddlers while they played a feedback-guided game on a touchscreen. Electrophysiological results show differential brain activity for feedback with a more negative deflection for incorrect than correct outcomes, resembling the adult FRN. This provides the first neural evidence for feedback processing in toddlers. Notably, FRN amplitudes were predictive of adaptive behavior: the stronger the differential brain activity for feedback, the better the toddlers' adaptive performance during the game. Thus, already in early childhood toddlers' feedback-guided performance directly relates to the functionality of their neural feedback processing. Implications for early feedback-based learning as well as structural and functional brain development are discussed.