Functional asymmetry and interhemispheric cooperation in the perception of emotions from facial expressions

Department of Psychology and Center for Cognitive Science, University of Turin, Via Po 14, 10123, Turin, Italy.
Experimental Brain Research (Impact Factor: 2.04). 06/2006; 171(3):389-404. DOI: 10.1007/s00221-005-0279-4
Source: PubMed


The present study used the redundant target paradigm on healthy subjects to investigate functional hemispheric asymmetries and interhemispheric cooperation in the perception of emotions from faces. In Experiment 1 participants responded to checkerboards presented either unilaterally to the left (LVF) or right visual half field (RVF), or simultaneously to both hemifields (BVF), while performing a pointing task for the control of eye movements. As previously reported (Miniussi et al. in J Cogn Neurosci 10:216-230, 1998), redundant stimulation led to shorter latencies for stimulus detection (bilateral gain or redundant target effect, RTE) that exceeded the limit for a probabilistic interpretation, thereby validating the pointing procedure and supporting interhemispheric cooperation. In Experiment 2 the same pointing procedure was used in a go/no-go task requiring subjects to respond when seeing a target emotional expression (happy or fearful, counterbalanced between blocks). Faster reaction times to unilateral LVF than RVF emotions, regardless of valence, indicate that the perception of positive and negative emotional faces is lateralized toward the right hemisphere. Simultaneous presentation of two congruent emotional faces, either happy or fearful, produced an RTE that cannot be explained by probability summation and suggests interhemispheric cooperation and neural summation. No such effect was present with BVF incongruent facial expressions. In Experiment 3 we studied whether the RTE for emotional faces depends on the physical identity between BVF stimuli, and we set a second BVF congruent condition in which there was only emotional but not physical or gender identity between stimuli (i.e. two different faces expressing the same emotion). The RTE and interhemispheric cooperation were present also in this second BVF congruent condition. This shows that emotional congruency is the sufficient condition for the RTE to take place in the intact brain and that the cerebral hemispheres can interact in spite of physical differences between stimuli.

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Available from: Beatrice de Gelder, Oct 09, 2015
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    • "These findings demonstrate a causal link between early right (but not left) M1 activity and visual perception. This link fits with the notion that sensorimotor networks in the right hemisphere support emotion and attention processing (Adolphs et al. 2000; Pourtois et al. 2004; Tamietto et al. 2006; Beraha et al. 2012) and appears also in line with the study of Pitcher et al. (2008) who found that TMS interference with early right somatosensory cortex activity (*100–170 ms) impaired visual recognition of facial expressions. While this latter study has been interpreted as strong evidence for embodied simulation accounts, it should be noted that the paradigm used by Pitcher et al. (2008) could not directly demonstrate the nature of somatosensory activation during emotion perception, because only behavioral data were acquired. "
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    ABSTRACT: Studies indicate that perceiving emotional body language recruits fronto-parietal regions involved in action execution. However, the nature of such motor activation is unclear. Using transcranial magnetic stimulation (TMS) we provide correlational and causative evidence of two distinct stages of motor cortex engagement during emotion perception. Participants observed pictures of body expressions and categorized them as happy, fearful or neutral while receiving TMS over the left or right motor cortex at 150 and 300 ms after picture onset. In the early phase (150 ms), we observed a reduction of excitability for happy and fearful emotional bodies that was specific to the right hemisphere and correlated with participants' disposition to feel personal distress. This 'orienting' inhibitory response to emotional bodies was also paralleled by a general drop in categorization accuracy when stimulating the right but not the left motor cortex. Conversely, at 300 ms, greater excitability for negative, positive and neutral movements was found in both hemispheres. This later motor facilitation marginally correlated with participants' tendency to assume the psychological perspectives of others and reflected simulation of the movement implied in the neutral and emotional body expressions. These findings highlight the motor system's involvement during perception of emotional bodies. They suggest that fast orienting reactions to emotional cues-reflecting neural processing necessary for visual perception-occur before motor features of the observed emotional expression are simulated in the motor system and that distinct empathic dispositions influence these two neural motor phenomena. Implications for theories of embodied simulation are discussed.
    Brain Structure and Function 07/2014; 220(5). DOI:10.1007/s00429-014-0825-6 · 5.62 Impact Factor
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    • "In some aspects , they may cooperate to perceive emotions [ Tamietto et al . , 2006 ] and avoid false memories [ Bergert , 2008 ] . In other aspects , they compete for domi - nance and inhibit the contralateral hemisphere [ Daskalakis et al . , 2002 ] . A remarkable finding by Sprague [ 1966 ] showed that cat ' s left superior colliculus inhibits the right hemisphere after the resections of the right visually re - spon"
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    Human Brain Mapping 10/2013; 34(10). DOI:10.1002/hbm.22093 · 5.97 Impact Factor
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    • "slower RTs for negative stimuli; e.g. [42]–[45]) where categorization tasks were carried out. The difference might depend on the paradigms used and the investigated processes. "
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    ABSTRACT: Facial emotions and emotional body postures can easily grab attention in social communication. In the context of faces, gaze has been shown as an important cue for orienting attention, but less is known for other important body parts such as hands. In the present study we investigated whether hands may orient attention due to the emotional features they convey. By implying motion in static photographs of hands, we aimed at furnishing observers with information about the intention to act and at testing if this interacted with the hand automatic coding. In this study, we compared neutral and frontal hands to emotionally threatening hands, rotated along their radial-ulnar axes in a Sidedness task (a Simon-like task based on automatic access to body representation). Results showed a Sidedness effect for both the palm and the back views with either neutral and emotional hands. More important, no difference was found between the two views for neutral hands, but it emerged in the case of the emotional hands: faster reaction times were found for the palm than the back view. The difference was ascribed to palm views' "offensive" pose: a source of threat that might have raised participants' arousal. This hypothesis was also supported by conscious evaluations of the dimensions of valence (pleasant-unpleasant) and arousal. Results are discussed in light of emotional feature coding.
    PLoS ONE 11/2012; 7(11):e49011. DOI:10.1371/journal.pone.0049011 · 3.23 Impact Factor
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