Acoustic Communication of Emotions: Processing of Emotional Prosody. An Investigation on Single Word Level using fMRI

Perception of emotional prosody plays an important role in every day social life. However, the underlying neuronal circuits are far from being identified. The objective of our study was to find out more about the neuronal networks involved in the processing of emotional speech on the single word level by means of fMRI. 13 young healthy subjects were tested in an auditory oddball paradigm where frequent standard words (“Anna“, p=0.7) and infrequent target words (“Anni“, p=0.1) were presented via headphones. The subjects had to press a button each time they heard the target word “Anni“. Both words, standard and the target, were spoken in a neutral tone. Additionally, infrequent words “Anna“ spoken in a happy (p=0.1) or sad (p=0.1) tone were presented as emotional oddballs. Functional MR images were acquired for each stimulus and then statistical parametrical maps (SPMs) were calculated for each subject and for a one-sample t-test. The contrasts “happy vs. neutral condition“ and “sad vs. neutral condition“ revealed activations in the middle gyrus of the temporal lobe and in the frontal opercular cortex bilaterally but with the main focus on the right side, suggesting a lateralization of emotional prosody processing to the right hemisphere already on the single word level. The results are discussed with respect to the relevant literature, the ecological validity and the limits of the experiment.