Affect-specific activation of shared networks for perception and execution of facial expressions

Abstract

Previous studies have shown overlapping neural activations for observation and execution or imitation of emotional facial expressions. These shared representations have been assumed to provide indirect evidence for a human mirror neuron system, which is suggested to be a prerequisite of action comprehension. We aimed at clarifying whether shared representations in and beyond human mirror areas are specifically activated by affective facial expressions or whether they are activated by facial expressions independent of the emotional meaning. During neuroimaging, participants observed and executed happy and non-emotional facial expressions. Shared representations were revealed for happy facial expressions in the pars opercularis, the precentral gyrus, in the superior temporal gyrus/medial temporal gyrus (MTG), in the pre-supplementary motor area and in the right amygdala. All areas showed less pronounced activation in the non-emotional condition. When directly compared, significant stronger neural responses emerged for happy facial expressions in the pre-supplementary motor area and in the MTG than for non-emotional stimuli. We assume that activation of shared representations depends on the affect and (social) relevance of the facial expression. The pre-supplementary motor area is a core-shared representation-structure supporting observation and execution of affective contagious facial expressions and might have a modulatory role during the preparation of executing happy facial expressions.

Positive Facial Affect – An fMRI Study on the Involvement of Insula and Amygdala

“…During observation the bilateral ventral amygdala was activated, whereas the bilateral dorsal amygdala was involved in smile execution. Contrary, shared representations of observation and execution of happy facial expressions were found in the same part of the bilateral amygdala [20].…”

“…Accordingly, 27 out of 32 participants were included in the final analyses (mean age: 24.6 years old ( SD  = 5.4); averaged school education: 12.9 years ( SD  = 0.6)). Data from all subjects were published in a previous study focusing on shared representations during observation and execution of facial expressions [20].…”

“…The stimuli were presented with MR-compatible goggles (Resonance Technology, Inc. Northridge, CA) using the Presentation© software package v.11.0 (Neurobehavioral Systems, Inc., Albany, CA). The evaluation of the stimulus material is described in detail Kircher and colleagues [20].…”

“…Data processing and statistic analyses (see also [20]) of the imaging data were performed using SPM5 (Wellcome Department of Imaging Neuroscience, London, UK) implemented in Matlab 7.2 (Mathworks Inc., Sherborn, MA, USA). The first five EPI volumes were discarded to allow for T1 equilibration.…”

“…The first six conditions of the experiment are described detailed in Kircher et al [20]. In this previous study, conjoint activations of observation and execution were presented.…”