Context effects on the processing hierarchy of vocal expressions

Context is crucial for interpreting emotional expressions. Behavioural work has consistently demonstrated the powerful impact of emotional context on disambiguating affective expressions within and across modalities. A theoretical framework suggests that context affects vocal emotion perception at all stages of the neural processing hierarchy, including primary auditory cortex (Schirmer and Kotz 2006). Using functional neuroimaging, we explored how emotional context images influence the perception of subsequently presented vocal emotional morphs taken from fear to pleasure continua. Morphs were embedded in a balanced sequence to enable the investigation of repetition suppression effects, while context images were blocked by emotion. Results revealed that emotionally congruent context-morph pairings enhanced activation in bilateral superior temporal gyri, including bilateral primary auditory cortex. In contrast, emotional incongruence activated bilateral inferior frontal gyri, regions typically associated with domain-general conflict resolution. To determine whether the activation in primary auditory cortex reflects feedforward or feedback processing, we analysed the effects of context on adaptation to the morphs. Adaptation to vocal emotion was not differentially modulated by context type. Our findings suggest that context information is initially processed independently of the auditory signal and integrated after the adaptation stage, with contextual influences on sensory cortex mediated via feedback mechanisms.