Sustained happiness? Lack of repetition suppression in right-ventral visual cortex for happy faces

Abstract

Emotional stimuli have been shown to preferentially engage initial attention but their sustained effects on neural processing remain largely unknown. The present study evaluated whether emotional faces engage sustained neural processing by examining the attenuation of neural repetition suppression to repeated emotional faces. Repetition suppression of neural function refers to the general reduction of neural activity when processing a repeated stimulus. Preferential processing of emotional face stimuli, however, should elicit sustained neural processing such that repetition suppression to repeated emotional faces is attenuated relative to faces with no emotional content. We measured the reduction of functional magnetic resonance imaging signals associated with immediate repetition of neutral, angry and happy faces. Whereas neutral faces elicited the greatest suppression in ventral visual cortex, followed by angry faces, repetition suppression was the most attenuated for happy faces. Indeed, happy faces showed almost no repetition suppression in part of the right-inferior occipital and fusiform gyri, which play an important role in face-identity processing. Our findings suggest that happy faces are associated with sustained visual encoding of face identity and thereby assist in the formation of more elaborate representations of the faces, congruent with findings in the behavioral literature.

Aberrant neurocognitive processing of fear in young girls with Turner syndrome

“…This indicates that the emotion processing circuit for happy faces allows for correct identification of emotion in TS, therefore between-group differences in this activation pattern may be attributable to impairments in face-identity rather than emotion classification circuitry. In fact, previous literature reports that suppression of activity in this region after repeated exposure to stimuli is attenuated for happy relative to other facial emotions (Suzuki et al, 2011), although face identity is eventually thought to be mastered via semantic associations in a top-down feedback loop (Henson et al, 2002). Therefore, this finding is in keeping with our overall hypothesis that top-down inhibitory feedback is likely impaired in girls with TS compared with controls.…”

“…In fact, even beyond its inclusion in the core network for face-specific visual analysis (Haxby et al, 2000), the right fusiform plays a specialized function in face identification. Interestingly, activation in the face identity processing region is thought to occur uniquely for happy faces (Henson et al, 2002;Suzuki et al, 2011). One interpretation may be that girls with TS have increased responsiveness to happy faces compared with control peers, however this is unlikely given that the right fusiform rather than the ventral visual face network at large is activated.…”

Spatiotemporal dynamics in human visual cortex rapidly encode the emotional content of faces

“…In particular, a stronger repetition suppression effect was shown for fearful faces than for neutral faces in both fMRI and MEG (Ishai, Pessoa, Bikle, & Ungerleider, 2004; Ishai, Bikle, & Ungerleider, 2006), although this effect was only present for target faces that were the object of a working memory task. On the other hand, repetition suppression was shown to be absent for happy faces and reduced for angry faces as compared with neutral faces in an fMRI study with an implicit paradigm (Suzuki et al, 2011). Such a pattern is inconsistent with a large contribution of repetition suppression effects to the current results.…”

Dog behavior but not frontal brain reaction changes in repeated positive interactions with a human: A non-invasive pilot study using functional near-infrared spectroscopy (fNIRS)

“…The contrast between the clear behavioral changes over time and constant hemodynamic reactions would be consistent with the assumption that the behavior indicated the level of arousal in the dogs, which decreased with each repetition due to habituation, whereas the cortical hemodynamic reaction reflected the valence of the stimulus, which stayed the same throughout the repetitions. An absence of change, that is, a constant activation of the right-inferior occipital and fusiform gyri was also observed in humans subjected repeatedly to happy faces [24], even though those authors attributed the absent effect to processing face identity rather than valence. Behavior as indicators of arousal and frontal cortical activity as an indicator of valence is admittedly a strong interpretation but, at the same time, parsimonious.…”