Prioritized neural processing of social threats during perceptual decision-making.

Emotional signals, notably those signaling threat, benefit from prioritized processing in the human brain. Yet, it remains unclear whether perceptual decisions about the emotional, threat-related aspects of stimuli involve specific or similar neural computations compared to decisions about their non-threatening/non-emotional components. We developed a novel behavioral paradigm in which participants performed two different detection tasks (emotion vs. color) on the same, two-dimensional visual stimuli. First, electroencephalographic (EEG) activity in a cluster of central electrodes reflected the amount of perceptual evidence around 100 ms following stimulus onset, when the decision concerned emotion, not color. Second, participants' choice could be predicted earlier for emotion (240 ms) than for color (380 ms) by the mu (10 Hz) rhythm, which reflects motor preparation. Taken together, these findings indicate that perceptual decisions about threat-signaling dimensions of facial displays are associated with prioritized neural coding in action-related brain regions, supporting the motivational value of socially relevant signals.

Kea, Nestor notabilis, achieve cooperation in dyads, triads, and tetrads when dominants show restraint.

Animal cooperation in the wild often involves multiple individuals that must tolerate each other in close proximity. However, most cooperation experiments in the lab are done with two animals, that are often also physically separated. Such experiments are useful for answering some pertinent questions, for example about the understanding of the role of the partner and strategies of partner control, but say little about factors determining successful cooperation with multiple partners in group settings. We explored the influence of dominance, rank distance, tolerance, affiliation, and coordination by testing kea parrots with a box requiring two, three, or four chains to be pulled simultaneously to access food rewards. The reward could be divided unevenly, but not monopolized completely. Eventually dyadic, triadic, and tetradic cooperation tasks were solved, showing that non-human animals are capable of tetradic cooperation in an experimental setup. Starting with two chains, we found that in a dyad monopolization of the box by the highest-ranking bird was the largest obstacle preventing successful cooperation. High-ranking birds learned to restrain themselves from monopolizing the box during a single session in which monopolization was hindered by the presence of a large number of birds. Thereafter, restraint by dominants remained the strongest factor determining success in the first trial in dyadic, triadic, and tetradic setups. The probability of success increased with the degree of restraint shown by all dominant subjects present. Previous experience with the task contributed to success in subsequent sessions, while increasing rank distance reduced success notably in the four-chain setup.

Emotional learning promotes perceptual predictions by remodeling stimulus representation in visual cortex.

Emotions exert powerful effects on perception and memory, notably by modulating activity in sensory cortices so as to capture attention. Here, we examine whether emotional significance acquired by a visual stimulus can also change its cortical representation by linking neuronal populations coding for different memorized versions of the same stimulus, a mechanism that would facilitate recognition across different appearances. Using fMRI, we show that after pairing a given face with threat through conditioning, viewing this face activates the representation of another viewpoint of the same person, which itself was never conditioned, leading to robust repetition-priming across viewpoints in the ventral visual stream (including medial fusiform, lateral occipital, and anterior temporal cortex). We also observed a functional-anatomical segregation for coding view-invariant and view-specific identity information. These results indicate emotional signals may induce plasticity of stimulus representations in visual cortex, serving to generate new sensory predictions about different appearances of threat-associated stimuli.

[Atypical perception processing and facial emotion disorder in autism]. / Les anomalies du traitement des émotions faciales dans l'autisme : un trouble de la perception globale.

INTRODUCTION: Autistic syndrome is defined by several abnormalities, mainly affecting social interaction skills. Disorders of the processes of processing facial and emotional stimuli, and particularly avoidance of gaze, have also been reported in this disorder. Some authors have suggested that these abnormalities may be explained, or at least contributed to, by the social disorder observed in this syndrome. The aim of this study was therefore to improve the understanding of the processes involved in perception AND the representation of faces expressing emotion in subjects with autism spectrum disorders (ASDs). METHODS: Eleven children with ASDs (mean developmental age 7 years 11 months) and eleven normally developing children (mean age 7 years 9 months) took part in three experiments. The first involved overall discrimination of emotions using photographs of faces expressing six basic emotions, the second required local emotional discrimination on the basis of isolated elements of the face (photographs of eyes and mouths isolated from the rest of the face), and for the third the children were asked to create faces expressing emotions by means of a jig-saw puzzle format, using photographs of isolated elements of the face (overall representation necessitating local discrimination). RESULTS: Our findings revealed that the normally developing children had difficulties with the process of local discrimination of emotions: their performance improved when overall perception was possible. In contrast, and astonishingly, the children with ASD were more able to discriminate isolated eyes expressing emotion than the controls, but their performance declined when overall processing was required. DISCUSSION: Our results suggested that the emotional disorders observed in ASDs might be explained by greater skills in the processing of local information. This might explain the inability of children with ASDs to achieve coherent perception of their social environment and might also lead to the withdrawal that is characteristic of this disorder. These results also suggest that the gaze avoidance that is characteristic of individuals with ASDs is eliminated when eyes are presented alone. This gaze avoidance therefore seems to be related to the complexity and variability of this type of stimulus and not to the social nature of the stimulus.