On the orbito-striatal interface in (acoustic) emotional processing

This chapter provides a comprehensive overview of the functional roles of the orbitofrontal cortex (OFC) and the basal ganglia (BG) in the processing of vocal emotional expressions in humans. We suggest that the two structures may interface during the integration of verbal and non-verbal vocal emotional expressions during late, cognitive processing stages as evidenced by recent event-related brain potential (ERP) and behavioural patient evidence. In accordance with our recent network model on emotional speech processing (Schirmer and Kotz 2006), we propose that the BG and the OFC are critically involved in the integration and evaluation of vocal emotional expressions. However, the overview will also reveal that the OFC is functionally differentiated and may thus respond to emotional expressions during both early automatic and late controlled, evaluative processing stages. Which processing stages the OFC responds to may critically hinge on the nature of stimulus and task type. As both structural and functional subcomponents of the orbito-striatal interface appear to be comparable in humans and non-human primates, we finally speculate that this system may be involved in the processing of emotional vocalizations across different species.