Neural Response to Emotional Prosody in Schizophrenia and in Bipolar Affective Disorder

Background: Evidence suggests a reversal of the normal left-lateralised response to speech in schizophrenia.

Aims: To test the brain's response to emotional prosody in schizophrenia and bipolar disorder.

Method: BOLD contrast functional magnetic resonance imaging of subjects while they passively listened or attended to sentences that differed in emotional prosody.

Results: Patients with schizophrenia exhibited normal right-lateralisation of the passive response to 'pure' emotional prosody and relative left-lateralisation of the response to unfiltered emotional prosody. When attending to emotional prosody, patients with schizophrenia activated the left insula more than healthy controls. When listening passively, patients with bipolar disorder demonstrated less activation of the bilateral superior temporal gyri in response to pure emotional prosody, and greater activation of the left superior temporal gyrus in response to unfiltered emotional prosody. In both passive experiments, the patient groups activated different lateral temporal lobe regions.

Conclusions: Patients with schizophrenia and bipolar disorder may display some left-lateralisation of the normal right-lateralised temporal lobe response to emotional prosody.