The study used EEG to measure brain activity in the medial frontal cortex while participants completed a monetary gambling task. Researchers found a negative polarity ERP beginning around 200ms after outcome stimuli, largest at the Fz electrode site in the anterior cingulate cortex, which they called the medial frontal negativity (MFN). The MFN responded more to monetary losses than gains and covaried with participants' subsequent risk-taking behavior, suggesting it rapidly processes the motivational impact of rewards and punishments.