“It’s not what you say, but how you say it”: a reciprocal temporo-frontal network for affective prosody

Leitman Leitman

doi:10.3389/fnhum.2010.00019

Abstract

Humans communicate emotion vocally by modulating acoustic cues such as pitch, intensity and voice quality. Research has documented how the relative presence or absence of such cues alters the likelihood of perceiving an emotion, but the neural underpinnings of acoustic cue-dependent emotion perception remain obscure. Using functional magnetic resonance imaging in 20 subjects we examined a reciprocal circuit consisting of superior temporal cortex, amygdala and inferior frontal gyrus that may underlie affective prosodic comprehension. Results showed that increased saliency of emotion-specific acoustic cues was associated with increased activation in superior temporal cortex [planum temporale (PT), posterior superior temporal gyrus (pSTG), and posterior superior middle gyrus (pMTG)] and amygdala, whereas decreased saliency of acoustic cues was associated with increased inferior frontal activity and temporo-frontal connectivity. These results suggest that sensory-integrative processing is facilitated when the acoustic signal is rich in affective information, yielding increased activation in temporal cortex and amygdala. Conversely, when the acoustic signal is ambiguous, greater evaluative processes are recruited, increasing activation in inferior frontal gyrus (IFG) and IFG STG connectivity. Auditory regions may thus integrate acoustic information with amygdala input to form emotion-specific representations, which are evaluated within inferior frontal regions.

Highlights

When we communicate vocally, it is often not just what we say – but how we say it – that matters
We present the first study to experimentally examine neural correlates of these acoustic cue-dependent perceptual changes
There we found that the log transform of fundamental frequency standard deviation (F0SD) ranges of happy and fear and the HF500 range for anger were statistically distinct from the other emotions as a whole and that they provided the single strongest correlate of subject performance

Summary

Introduction

It is often not just what we say – but how we say it – that matters. In expressing joy our voices become increasingly melodic, while our voicing of sadness is more often flat and monotonic. Such prosodic aspects of speech precede formal language acquisition, reflecting the evolutionary importance of communicating emotion (Fernald, 1989). Anger, happiness, and fear are typically characterized by high mean pitch and voice intensity, whereas sadness expressions are associated with low mean pitch and intensity. Anger and happiness expressions typically have large pitch variability, whereas fear and sadness expressions have small pitch variability. Anger expressions typically have a large proportion of high-frequency energy in the spectrum, whereas sadness has less high-frequency energy (as the proportion of high-frequency energy increases, the voice sounds sharper and less soft). We present the first study to experimentally examine neural correlates of these acoustic cue-dependent perceptual changes

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