Comparative processing of emotional prosody and semantics following basal ganglia infarcts: ERP evidence of selective impairments for disgust and fear.

There is evidence from neuroimaging and clinical studies that functionally link the basal ganglia to emotional speech processes. However, in most previous studies, explicit tasks were administered. Thus, the underlying mechanisms substantiating emotional speech are not separated from possibly process-related task effects. Therefore, the current study tested emotional speech processing in an event-related potential (ERP) experiment using an implicit emotional processing task (probe verification). The interactive time course of emotional prosody in the context of emotional semantics was investigated using a cross-splicing method. As previously demonstrated, combined prosodic and semantic expectancy violations elicit N400-like negativities irrespective of emotional categories in healthy listeners. In contrast, basal ganglia patients show this negativity only for the emotions of happiness and anger, but not for fear or disgust. The current data serve as first evidence that lesions within the left basal ganglia affect the comparative online processing of fear and disgust prosody and semantics. Furthermore, the data imply that previously reported emotional speech recognition deficits in basal ganglia patients may be due to misaligned processing of emotional prosody and semantics.