arXiv subjects

Paola Sessa

Publications and source records attributed to Paola Sessa.

3 recordsLinked to original sources

arXiv2020

Altering sensorimotor simulation impacts early stages of facial expression processing depending on individual differences in alexithymic traits

Simulation models of facial expressions suggest that posterior visual areas and brain areas underpinning sensorimotor simulations might interact to improve facial expression processing. According to these models, facial mimicry may contribute to the visual processing of facial expressions by influencing early stages. The aim of the present study was to assess whether/how early sensorimotor simulation influences early stages of face processing. A secondary aim was to investigate the relationship between alexithymic traits and sensorimotor simulation. We monitored P1 and N170 components of the event-related potentials (ERP) in participants performing a fine discrimination task of facial expressions while implementing an animal discrimination task as control condition. In half of the experiment, participants could freely use their facial mimicry whereas in the other half, they had their facial mimicry blocked by a gel. Our results revealed that, on average, both P1 and N170 ERP components were not sensitive to mimicry manipulation. However, when taking into account alexithymic traits, a scenario corroborating sensorimotor simulation models emerged, with two dissociable temporal windows affected by mimicry manipulation as a function of alexithymia levels. Specifically, as a function of mimicry manipulation, individuals with lower alexithymic traits showed modulations of the P1 amplitude, while individuals with higher alexithymic traits showed modulations of the later N170). Furthermore, connectivity analysis at the scalp level suggested increased connectivity between sensorimotor and extrastriate visual regions in individuals with lower alexithymic traits compared to individuals with higher alexithymic traits. Overall, we interpreted these ERPs modulations as compensative visual processing under conditions of interference on the sensorimotor processing.

q-bio.NC↗

arXiv2018

Neural measures of the causal role of observers' facial mimicry on visual working memory for facial expressions

Simulation models of facial expressions propose that sensorimotor regions may increase the clarity of facial expressions representations in extrastriate areas. We monitored the event-related potential marker of visual working memory (VWM) representations, namely the sustained posterior contralateral negativity (SPCN), also termed contralateral delay activity (CDA), while participants performed a change detection task including to-be-memorized faces with different intensities of anger. In one condition participants could freely use their facial mimicry during the encoding/VWM maintenance of the faces, while in a different condition, participants had their facial mimicry blocked by a gel. Notably, SPCN amplitude was reduced for faces in the blocked mimicry condition when compared to the free mimicry condition. This modulation interacted with the empathy levels of participants such that only participants with medium-high empathy scores showed such reduction of the SPCN amplitude when their mimicry was blocked. The SPCN amplitude was larger for full expressions when compared to neutral and subtle expressions, while subtle expressions elicited lower SPCN amplitudes than neutral faces. These findings provide evidence of a functional link between mimicry and VWM for faces, and further shed light on how this memory system may receive feedbacks from sensorimotor regions during the processing of facial expressions.

q-bio.NC↗

arXiv2018

Out of sight out of mind: Perceived physical distance between the observer and someone in pain shapes observer's neural empathic reactions

Social and affective relations may shape empathy to others' affective states. Previous studies also revealed that people tend to form very different mental representations of stimuli on the basis of their physical distance. In this regard, embodied cognition proposes that different physical distances between individuals activate different interpersonal processing modes, such that close physical distance tends to activate the interpersonal processing mode typical of socially and affectively close relationships. In Experiment 1, two groups of participants were administered a pain decision task involving upright and inverted face stimuli painfully or neutrally stimulated, and we monitored their neural empathic reactions by means of event-related potentials (ERPs) technique. Crucially, participants were presented with face stimuli of one of two possible sizes in order to manipulate retinal size and perceived physical distance, roughly corresponding to the close and far portions of social distance. ERPs modulations compatible with an empathic reaction were observed only for the group exposed to face stimuli appearing to be at a close social distance from the participants. This reaction was absent in the group exposed to smaller stimuli corresponding to face stimuli observed from a far social distance. In Experiment 2, one different group of participants was engaged in a match-to-sample task involving the two-size upright face stimuli of Experiment 1 to test whether the modulation of neural empathic reaction observed in Experiment 1 could be ascribable to differences in the ability to identify faces of the two different sizes. Results suggested that face stimuli of the two sizes could be equally identifiable. In line with the Construal Level and Embodied Simulation theoretical frameworks, we conclude that perceived physical distance may shape empathy as well as social and affective distance.

q-bio.NC↗