Population coding of affect across stimuli, modalities and individuals

The authors found human neuroimaging evidence that entire valence spectrum is represented as a collective pattern in regional neural activity, with sensory-specific signals in the ventral temporal and anterior insular cortices and abstract codes in the orbitofrontal cortices. In this way, the subjective quality of affect can be objectively quantified across stimuli, modalities and people. It remains unclear how the brain represents external objective sensory events alongside our internal subjective impressions of them—affect. Representational mapping of population activity evoked by complex scenes and basic tastes in humans revealed a neural code supporting a continuous axis of pleasant-to-unpleasant valence. This valence code was distinct from low-level physical and high-level object properties. Although ventral temporal and anterior insular cortices supported valence codes specific to vision and taste, both the medial and lateral orbitofrontal cortices (OFC) maintained a valence code independent of sensory origin. Furthermore, only the OFC code could classify experienced affect across participants. The entire valence spectrum was represented as a collective pattern in regional neural activity as sensory-specific and abstract codes, whereby the subjective quality of affect can be objectively quantified across stimuli, modalities and people.