Modality-general representations of valences perceived from visual and auditory modalities

Valence is a dimension of emotion and can be either positive, negative, or neutral. Valences can be expressed through the visual and auditory modalities, and the valences of each modality can be conveyed by different types of stimuli (face, body, voice or music). This study focused on the modality-general representations of valences, that is, valence information can be shared across not only visual and auditory modalities but also different types of stimuli within each modality. Functional magnetic resonance imaging (fMRI) data were collected when subjects made affective judgment on silent videos (face and body) and audio clips (voice and music). The searchlight analysis helped to locate four areas that might be sensitive to the representations of modality-general valences, including the bilateral postcentral gyrus, left middle temporal gyrus (MTG) and right middle frontal gyrus (MFG). Further cross-modal classification based on multivoxel pattern analysis (MVPA) was performed as a validation analysis, which suggested that only the left postcentral gyrus could successfully distinguish three valences (positive versus negative and versus neutral: PvsNvs0) across different types of stimuli (face, body, voice or music), and the classification was also successful in left MTG across the stimuli types of face and body. The univariate analysis further found the valence-specific activation differences across stimulus types in MTG. Our study showed that the left postcentral gyrus was informative to valence representations, and extended the research about valence representation that the modality-general representation of valences across not only visual and auditory modalities but also different types of stimuli within each modality.