Attentional and emotional interaction in face processing: a combined rTMS/fMRI study

Abstract

This study aimed at understanding whether the brain processes emotional stimulus independently of spatial attentional control. Two hypotheses are found in literature. In their studies, Vuilleumier and collaborators showed that fusiform activity is modulated by emotional expression (fear) despite the absence of attention toward the stimuli and that amygdala has a constant activation with or without attention. On the other hand, Pessoa et al. suggested that emotional stimuli processing requires intact attentional resources, then, attention toward emotional stimulus may increase amygdala activation. Nevertheless, an attentional top-down control from right frontal area (FEF) over visual cortex determinate available attentional resources (Corbetta et al., 2000 ; Schwartz et al., 2005 ; Ruff et al., 2009). In our study, we evaluated the link between attentional and emotional processes with the use of rTMS to inhibit cortical area involved in attentional control (FEF), and compared performances and cerebral activations in an attentional/emotional matching task (Vuilleumier et al., 2001). Forty healthy participants were recruited to perform an emotional matching task in the fMRI scan, without and after rTMS over FEF (n=20) vs. Vertex (control condition, n=20). If the inhibition of FEF activation reduces attentional control, the observation of a modulation in amygdala activity could correspond to an interaction between attentional and emotional networks.