Understanding emotional prosody activates right hemisphere regions

Background: Defects in expressing or understanding the affective or emotional tone of speech (aprosodias) have been associated with right hemisphere dysfunction, while defects of propositional language have been linked to left hemisphere disease. The brain regions involved in recognition of emotional prosody in healthy subjects is less clear. Objectives: To investigate the brain regions involved in understanding emotional prosody and to determine whether these differ from those involved in understanding emotion based on propositional content. Methods: We studied 13 healthy subjects using water labeled with radioactive oxygen 15 and positron emission tomography while they listened to 3 similar sets of spoken English sentences. In different tasks, their responses were based on the emotional propositional content, on the emotional intonation of the sentence (prosody), or on their ability to repeat the second word in the sentence (control). Results: Understanding propositional content activated the prefrontal cortex bilaterally, on the left more than on the right. In contrast, responding to the emotional prosody activated the right prefrontal cortex. Conclusion: Neurologically healthy subjects activate right hemisphere regions during emotional prosody recognition.