BRIEF REPORT Medial frontal negativity reflects learning from positive feedback

The ability to learn from the consequences of our actions is crucial for adaptive goal-directed behavior. We learn to avoid actions that lead to unfavorable outcomes and pursue actions that lead to desirable results. By recording event-related potentials (ERPs), we show that neural reinforcement learning signals associated with positive outcomes are predictive of subsequent learning of a sequence of motor actions: Positive feedback to a response that was later correctly repeated was associated with a larger Medial Frontal Negativity (MFN) compared to when it was not correctly repeated on a subsequent encounter. This finding adds to recent evidence suggesting that the function of the Anterior Cingulate Cortex is to establish associations between actions and their outcomes, both positive and negative. It has been shown that Anterior Cingulate Cortex (ACC) activity is reflected by a negative event-related potential (ERP) on the scalp (Dehaene, Posner, & Tucker, 1994; Miltner, Braun, & Coles, 1997). Such negative amplitude shifts are prominent when subjects commit response errors (Error-Related Negativity) or when they receive negative feedback (Feedback-Related Negativity). It has been suggested that these ERP components are associated with common neural processes (Nieuwenhuis, Holroyd, Mol, & Coles, 2004), and, for convenience, we will refer to them as Medial Frontal Negativity (MFN). A prominent theory holds that ACC activity in response to such negative events reflects a reinforcement learning (RL) process by which the organism learns to associate actions with negative outcomes (Holroyd & Coles, 2002). However, recent studies using electrophysiological recordings of single ACC cells in monkeys and also human imaging studies show that the ACC can also be activated by positive action outcomes, which suggests that it supports a more general mechanism to estab-lish action–outcome associations, by also learning from positiv