Abstract
Conflicting data from neurobehavioral studies of the perception of intonation (linguistic) and emotion (affective) in spoken language highlight the need to further examine how functional attributes of prosodic stimuli are related to hemispheric differences in processing capacity. Because of similarities in their acoustic profiles, intonation and emotion permit us to assess to what extent hemispheric lateralization of speech prosody depends on functional instead of acoustical properties. To examine how the brain processes linguistic and affective prosody, an fMRI study was conducted using Chinese, a tone language in which both intonation and emotion may be signaled prosodically, in addition to lexical tones. Ten Chinese and 10 English subjects were asked to perform discrimination judgments of intonation (I: statement, question) and emotion (E: happy, angry, sad) presented in semantically neutral Chinese sentences. A baseline task required passive listening to the same speech stimuli (S). In direct between-group comparisons, the Chinese group showed left-sided frontoparietal activation for both intonation (I vs. S) and emotion (E vs. S) relative to baseline. When comparing intonation relative to emotion (I vs. E), the Chinese group demonstrated prefrontal activation bilaterally; parietal activation in the left hemisphere only. The reverse comparison (E vs. I), on the other hand, revealed that activation occurred in anterior and posterior prefrontal regions of the right hemisphere only. These findings show that some aspects of perceptual processing of emotion are dissociable from intonation, and, moreover, that they are mediated by the right hemisphere.