Improved categorization of subtle facial expressions modulates Late Positive Potential

摘要

Biases in facial expression recognition can be reduced successfully using feedback-based training tasks.udHere we investigate with event-related potentials (ERPs) at which stages of stimulus processing emotion-related modulations are influenced by training. Categorization of subtle facial expressions (morphed from neutral to happy, sad or surprise) was trained with correct-response feedback on each trial. ERPs were recorded before and after trainingudwhile participants categorized facial expressions without response feedback. Behavioral data demonstrated largeudimprovements in categorization of subtle facial expression which transferred to new face models not used during training. ERPs were modulated by training from 450 ms poststimulus onward, characterized by a more gradual increaseudin P3b/Late Positive Potential (LPP) amplitude as expression intensity increased. This effect was indistinguishable forudfaces used for training and for new faces. It was proposed that training elicited a more fine-grained analysis of facialudinformation for all subtle expressions, resulting in improved recognition and enhanced emotional motivational salienceud(reflected in P3b/LPP amplitude) of faces previously categorized as expressing no emotion. �