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.
Facial expressions may have originated from a primitive sensory regulatory function that was then co-opted and further shaped for the purposes of social utility. In the research reported here, we tested such a hypothesis by investigating the functional origins of fear expressions for both the expresser and the observer. We first found that fear-based eye widening enhanced target discrimination in the available visual periphery of the expresser by 9.4%. We then found that fear-based eye widening enhanced observers’ discrimination of expressers’ gaze direction and facilitated observers’ responses when locating eccentric targets. We present evidence that this benefit was driven by neither the perceived emotion nor attention but, rather, by an enhanced physical signal originating from greater exposure of the iris and sclera. These results highlight the coevolution of sensory and social regulatory functions of emotional expressions by showing that eye widening serves to enhance processing of important environmental events in the visual fields of both expresser and observer.
The mammalian tongue contains gustatory receptors tuned to basic taste types, providing an evolutionarily old hedonic compass for what and what not to ingest. Although representation of these distinct taste types is a defining feature of primary gustatory cortex in other animals, their identification has remained elusive in humans, leaving the demarcation of human gustatory cortex unclear. Here we used distributed multivoxel activity patterns to identify regions with patterns of activity differentially sensitive to sweet, salty, bitter, and sour taste qualities. These were found in the insula and overlying operculum, with regions in the anterior and middle insula discriminating all tastes and representing their combinatorial coding. These findings replicated at super-high 7 T field strength using different compounds of sweet and bitter taste types, suggesting taste sensation specificity rather than chemical or receptor specificity. Our results provide evidence of the human gustatory cortex in the insula.
Recent advances in our understanding of information states in the human brain have opened a new window into the brain's representation of emotion. While emotion was once thought to constitute a separate domain from cognition, current evidence suggests that all events are filtered through the lens of whether they are good or bad for us. Focusing on new methods of decoding information states from brain activation, we review growing evidence that emotion is represented at multiple levels of our sensory systems and infuses perception, attention, learning, and memory. We provide evidence that the primary function of emotional representations is to produce unified emotion, perception, and thought (e.g., “That is a good thing”) rather than discrete and isolated psychological events (e.g., “That is a thing. I feel good”). The emergent view suggests ways in which emotion operates as a fundamental feature of cognition, by design ensuring that emotional outcomes are the central object of perception, thought, and action.
Numerous emotion researchers have asked their study participants to attend to the distinct feelings of arousal and valence, and self-report and physiological data have supported the independence of the two. We examined whether this dissociation reflects introspection about distinct emotional qualia or the way in which valence is measured. With either valence (Experiment 1) or arousal (Experiment 2) as the primary focus, when valence was measured using a bipolar scale (ranging from negative to positive), it was largely dissociable from arousal. By contrast, when two separate unipolar scales of pleasant and unpleasant valence were used, their sum was equivalent to feelings of arousal and its autonomic correlates. The association (or dissociation) of valence and arousal was related to the estimation (or nonestimation) of mixed-valence experiences, which suggests that the distinction between valence and arousal may reflect less the nature of emotional experience and more how it is measured. These findings further encourage use of unipolar valence scales in psychological measurement.
The presence of emotional stimuli results in a central/peripheral tradeoff effect in memory: memory for central details is enhanced at the cost of peripheral items. It has been assumed that emotion-modulated differences in memory are the result of differences in attention, but this has not been tested directly. The present experiment used eye movement monitoring as an index of overt attention allocation and mediation analysis to determine whether differences in attention were related to subsequent memory. Participants viewed negative and neutral scenes surrounded by three neutral objects and were then given a recognition memory test. The results revealed evidence in support of a central/peripheral tradeoff in both attention and memory. However, contrary with previous assumptions, whereas attention partially mediated emotion-enhanced memory for central pictures, it did not explain the entire relationship. Further, although centrally presented emotional stimuli led to decreased number of eye fixations toward the periphery, these differences in viewing did not contribute to emotion-impaired memory for specific details pertaining to the periphery. These findings suggest that the differential influence of negative emotion on central versus peripheral memory may result from other cognitive influences in addition to overt visual attention or on postencoding processes.