Differential hemispheric and visual stream contributions to ensemble coding of crowd emotion

Abstract

In crowds, where scrutinizing individual facial expressions is inefficient, humans can make snap judgments about the prevailing mood by reading “crowd emotion”. We investigated how the brain accomplishes this feat in a set of behavioral and fMRI studies. Participants were asked to either avoid or approach one of two crowds of faces presented in the left and right visual hemifields. Perception of crowd emotion was improved when crowd stimuli contained goal-congruent cues and was highly lateralized to the right hemisphere. The dorsal visual stream was preferentially activated in crowd emotion processing, with activity in the intraparietal sulcus and superior frontal gyrus predicting perceptual accuracy for crowd emotion perception, whereas activity in the fusiform cortex in the ventral stream predicted better perception of individual facial expressions. Our findings thus reveal significant behavioral differences and differential involvement of the hemispheres and the major visual streams in reading crowd versus individual face expressions.

Independence of viewpoint and identity in face ensemble processing

“…Last, little is currently known regarding the neural basis of ensemble processing. Recent work (Im et al, 2017) appears to implicate the dorsal visual stream in expression ensemble perception. At the same time, though, object ensembles seem to recruit the parahippocampal place area (Cant & Xu, 2012, a region classically associated with scene processing (Epstein & Kanwisher, 1998;Park, Brady, Greene, & Oliva, 2011).…”

Elucidating the Neural Representation and the Processing Dynamics of Face Ensembles

“…Despite growing interest in the behavioral study of facial summary representations (Whitney and Yamanashi Leib, 2018), the neural underpinnings of ensemble face encoding have received far less attention. Recent fMRI work (Im et al, 2017) has suggested that the perception of individual face emotions and that of crowd emotions recruit differentially the two visual streams, with the former relying more on the ventral stream and the latter relying more on the dorsal stream. However, ventral areas, such as the lateral occipital area and the parahippocampal place area, have also been critically implicated in object ensemble processing Xu, 2012, 2017).…”

An fMRI study of cognitive reappraisal in major depressive disorder and borderline personality disorder

“…Regarding the hypoactivations also observed in the medial OFC in patients with MDD, it should be noted that this region, like other medial prefrontal structures, has been shown to downregulate activity in subcortical structures (9), and, indeed, its functional connectivity with the amygdala is increased during threat-induced anxiety in healthy controls (43). According to our findings, the medial OFC of patients with MDD is probably not properly exerting this downregulatory input into emotion-processing structures, including, but not limited to, the amygdala (7,9).…”