Attention to individual identities modulates face processing

Am I the same person across my life span? An event-related brain potentials study of the temporal perspective in self-identity

While self-identity recognition has been largely explored, less is known on how self-identity changes as a function of time. The present work aims to explore the influence of the temporal perspective on self-identity by studying event-related brain potentials (ERP) associated with face processing. To this purpose, participants had to perform a recognition task in two blocks with different task demands: (i) identity recognition (self, close-friend, unknown), and (ii) life stage recognition (adulthood -current-, adolescence, and childhood). The results showed that the N170 component was sensitive to changes in the global face configuration when comparing adulthood with other life stages. The N250 was the earliest neural marker discriminating self from other identities and may be related to a preferential deployment of attentional resources to recognize own face. The P3 was a robust index of self-specificity, reflecting stimulus categorization and presumably adding an emotional value. The results of interest emerged for the subsequent late positive complex (LPC). The larger amplitude for the LPC to the self-face was probably associated with further personal significance. The LPC, therefore, was able to distinguish the continuity of the self over time (i.e., between current self and past selves). Likewise, this component also could discriminate, at each life stage, the self-identity from other identities (e.g., between past self and past close-friend). This would confirm a remarkable role of the LPC reflecting higher self-relevance processes. Taken together, the neural representation of oneself (i.e., "I am myself") seems to be stable and also updated across time.

Attentional Bias in specific symmetry and cleaning dimensions of obsessive-compulsive disorder

Attentional bias (AB) refers to increased allocation of attention on threat stimuli when compared to neutral stimuli. It is not clear if AB occurs in subjects with obsessive-compulsive disorder (OCD). We tested AB for symmetry and cleaning symptoms of OCD. Sixty-two patients with OCD and 40 healthy controls matched by gender, age and IQ, completed a computerized dot-probe task where two pictures (with symmetry or cleaning related content) were shown. The probe appeared in the location previously occupied by one of the pictures. Within-subjects linear mixed-effect models were used to investigate the effects of the factors: group (patients vs controls), OCD dimension (cleaning vs symmetry), task condition (neutral, congruent and incongruent), and the interaction among them. We also correlated AB scores with the clinical and demographic variables. No positive interaction resulted among the factors, but positive results were observed in group and condition, separately. Patients were significantly slower than controls (p-value = 0.014) (an effect that was accounted for by depression and anxiety symptoms and comorbidity) and the neutral condition was significantly faster when compared the other two conditions (congruent and incongruent, p-value = 0.013). No association was found between AB scores and clinical symptoms. There was no AB toward specific, content-related, stimuli in this sample of OCD patients.

Attentional orienting to own and others' hands

High-density electroencephalographic recordings were used to investigate the level of analysis at which attentional expectations modulate the processing of specific stimuli from the same perceptual category but differentiated in terms of a particular non-perceptual feature: body ownership. We used a task in which colour cues predicted whether a picture of a hand stimulus belonged to the participant or to somebody else. Participants were instructed to respond whether the target was a left or a right hand. Results revealed that the ERP pattern depended on stimulus ownership and attention orienting, which influenced the visual processing of own and someone else's hands differentially. Larger amplitude for others' than for own hands was shown at the N1 deflection (at the right hemisphere). Attentional effects were found at the P2 and P3 potentials. The P2 reflected an interaction between stimulus ownership and attentional orienting, due to a larger validity effect for others' hands. At the P3 level, the data showed a significant validity effect only for self-hand stimuli. In sum, our results suggest that (1) differences as a function of stimulus ownership can be detected at early levels of stimulus processing; (2) endogenous attention can be directed to exemplars within the same category, hand stimuli in this case; (3) the effects of attention are modulated by ownership.