Visual attention modulates the firing rate of neurons in many primate cortical areas. In V4, a cortical area in the ventral visual pathway, spatial attention has also been shown to reduce the tendency of neurons to fire closely separated spikes (burstiness). A recent model proposes that a single mechanism accounts for both the firing rate enhancement and the burstiness reduction in V4, but this has not been empirically tested. It is also unclear if the burstiness reduction by spatial attention is found in other visual areas and for other attentional types. We therefore recorded from single neurons in the medial superior temporal area (MST), a key motion-processing area along the dorsal visual pathway, of two rhesus monkeys while they performed a task engaging both spatial and feature-based attention. We show that in MST, spatial attention is associated with a clear reduction in burstiness that is independent of the concurrent enhancement of firing rate. In contrast, feature-based attention enhances firing rate but is not associated with a significant reduction in burstiness. These results establish burstiness reduction as a widespread effect of spatial attention. They also suggest that in contrast to the recently proposed model, the effects of spatial attention on burstiness and firing rate emerge from different mechanisms.

Emotional databases are important tools to study emotion recognition and their effects on various cognitive processes. Since, well-standardized large-scale emotional expression database is not available in India, we evaluated Radboud faces database (RaFD)—a freely available database of emotional facial expressions of adult Caucasian models, for Indian sample. Using the pictures from RaFD, we investigated the similarity and differences in self-reported ratings on emotion recognition accuracy as well as parameters of valence, clarity, genuineness, intensity and arousal of emotional expression, by following the same rating procedure as used for the validation of RaFD. We also systematically evaluated the universality hypothesis of emotion perception by analyzing differences in accuracy and ratings for different emotional parameters across Indian and Dutch participants. As the original Radboud database lacked arousal rating, we added this as a emotional parameter along with all other parameters. The results show that the overall accuracy of emotional expression recognition by Indian participants was high and very similar to the ratings from Dutch participants. However, there were significant cross-cultural differences in classification of emotion categories and their corresponding parameters. Indians rated certain expressions comparatively more genuine, higher in valence, and less intense in comparison to original Radboud ratings. The misclassifications/ confusion for specific emotional categories differed across the two cultures indicating subtle but significant differences between the cultures. In addition to understanding the nature of facial emotion recognition, this study also evaluates and enables the use of RaFD within Indian population.

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