Neural response to vocal emotional intensity in youth.

Previous research has identified regions of the brain that are sensitive to emotional intensity in faces, with some evidence for developmental differences in this pattern of response. However, comparable understanding of how the brain tracks linear variations in emotional prosody is limited-especially in youth samples. The current study used novel stimuli (morphing emotional prosody from neutral to anger/happiness in linear increments) to investigate whether neural response to vocal emotion was parametrically modulated by emotional intensity and whether there were age-related changes in this effect. Participants aged 8-21 years (n = 56, 52% female) completed a vocal emotion recognition task, in which they identified the intended emotion in morphed recordings of vocal prosody, while undergoing functional magnetic resonance imaging. Parametric analyses of whole-brain response to morphed stimuli found that activation in the bilateral superior temporal gyrus (STG) scaled to emotional intensity in angry (but not happy) voices. Multivariate region-of-interest analyses revealed the same pattern in the right amygdala. Sensitivity to emotional intensity did not vary by participants' age. These findings provide evidence for the linear parameterization of emotional intensity in angry vocal prosody within the bilateral STG and right amygdala. Although findings should be replicated, the current results also suggest that this pattern of neural sensitivity may not be subject to strong developmental influences.