Imitating expressions: emotion-specific neural substrates in facial mimicry

Abstract

Intentionally adopting a discrete emotional facial expression can modulate the subjective feelings corresponding to that emotion; however, the underlying neural mechanism is poorly understood. We therefore used functional brain imaging (functional magnetic resonance imaging) to examine brain activity during intentional mimicry of emotional and non-emotional facial expressions and relate regional responses to the magnitude of expression-induced facial movement. Eighteen healthy subjects were scanned while imitating video clips depicting three emotional (sad, angry, happy), and two 'ingestive' (chewing and licking) facial expressions. Simultaneously, facial movement was monitored from displacement of fiducial markers (highly reflective dots) on each subject's face. Imitating emotional expressions enhanced activity within right inferior prefrontal cortex. This pattern was absent during passive viewing conditions. Moreover, the magnitude of facial movement during emotion-imitation predicted responses within right insula and motor/premotor cortices. Enhanced activity in ventromedial prefrontal cortex and frontal pole was observed during imitation of anger, in ventromedial prefrontal and rostral anterior cingulate during imitation of sadness and in striatal, amygdala and occipitotemporal during imitation of happiness. Our findings suggest a central role for right inferior frontal gyrus in the intentional imitation of emotional expressions. Further, by entering metrics for facial muscular change into analysis of brain imaging data, we highlight shared and discrete neural substrates supporting affective, action and social consequences of somatomotor emotional expression.

An investigation of auditory contagious yawning

“…First, it has been reported that a patient with Foix-Chavany-Marie syndrome, a form of pseudo bulbar palsy resulting from bilateral opercular lesions, was unable to yawn voluntarily (whether spared involuntary yawning was spontaneous and/or contagious is unclear; Laurent-Vannier, Fadda, Laigle, Dusser, & Leroy-Malherbe, 1999). Second, and more convincingly, recent f MRI investigations of mouth movements have shown that very proximal, if not the same, regions of the pIFG in BA44 are activated when participants are asked to smile (Warren et al, 2006), imitate facial expressions (Lee, Josephs, Dolan, & Critchley, 2006;van der Gaag, Minderaa, & Keysers, 2007), manipulate small objects with their lips , listen to pure mouth sounds (e.g., crunching a piece of candy with the teeth, kissing, gurgling, crunching potato chips, finishing a can of soft drink with a straw; Gazzola et al, 2006), or listen to nonverbal human vocalizations (Warren et al, 2006).…”

“…Inferior prefrontal hemodynamic activity previously has been shown to increase with the amount of explicit imitation that a person exerts (e.g., using a facial imitation task; Lee et al, 2006), and more recently, this region has been shown to become active when unconscious word yawning does not always occur every time a yawn stimulus has been perceived. Although some yawn stimuli are more effective than others, a stimulus that is effective for one person may not be so for another.…”

“…For example, Lee et al (2006) found that the inferior prefrontal activity associated with the imitation of facial expressions was essentially eliminated when participants were asked to perform a gender discrimination task on the same facial stimuli. This, combined with similar findings from other studies, prompted Lee et al to speculate that the MN system may be attenuated when attention is focused on anything other than the posture or behavior to be imitated.…”

Processing of emotional vocalizations in bilateral inferior frontal cortex

“…Given the general view that the IFC is linked to several first-order executive processes, such as stimulus comparisons or the judgment of stimuli (Petrides, 2005), it might specifically serve several self-referenced or other-referenced social processes, such as the evaluation (Marumo et al, 2009), categorization (Frühholz et al, 2009, and memory encoding of emotional stimuli (Sergerie et al, 2005). The IFC might also be involved in controlling, overriding, or inhibiting behavioral and emotional responses (Aron et al, 2004;Dillon and Pizzagalli, 2007;Mitchell, 2011), as well as mirroring (Leslie et al, 2004), empathizing (Schulte-Ruther et al, 2007), or imitating the behavior of other individuals (Lee et al, 2006). All of these socially relevant processes can be regarded as first-order executive processes.…”

Why do I like you when you behave like me? Neural mechanisms mediating positive consequences of observing someone being imitated

“…Therefore a mismatch between the gestures planned and simulated for oneself (or the person seen from a first-person perspective) and the gestures simulated for the interaction partner might afford additional processing. This conflict hypothesis would therefore predict an enhanced involvement of brain areas related to conflict processing and negative effect including lateral orbitofrontal cortex (lOFC), anterior cingulate cortex (ACC) involved in detection of conflict, and dorsolateral prefrontal cortex (DLPFC) engaged to resolve the conflict 5 in the antimimicry condition (Buchel, Morris, Dolan & Friston, 1998;Carter & van Veen, 2007;Lee, Dolan & Critchley, 2008;Lee, Josephs, Dolan, & Critchley, 2006;O'Doherty et al, 2001;Small et al, 2001). …”