Increased N250 elicited by facial familiarity: An ERP study including the face inversion effect and facial emotion processing

The present study aims to explore how familiarity modulates the neural processing of faces under different conditions: upright or inverted, neutral or emotional. To this purpose, 32 participants (25 female; age: M = 27.7 years, SD = 9.3) performed two face/emotion identification tasks during EEG recording. In the first task, to study facial processing, three different categories of facial stimuli were presented during a target detection task: famous familiar faces, faces of loved ones, and unfamiliar faces. To explore the face inversion effect according to each level of familiarity, these facial stimuli were also presented upside down. In the second task, to study emotional face processing, an emotional identification task on personally familiar and unfamiliar faces was conducted. The behavioural results showed an improved performance in the identification of facial expressions of emotion with the increase of facial familiarity, consistent with the previous literature. Regarding electrophysiological results, we found increased amplitudes of the P100, N170, and N250 for inverted compared to upright faces, independently of their degree of familiarity. Moreover, we did not find familiarity effects at the P100 and N170 time-windows, but we found that N250 amplitude was larger for personally familiar compared to unfamiliar faces. This result supports the reasoning that the facial familiarity increases the neural activity during the N250 time-window, which may be explained by the processing of additional information prompted by the viewing of our loved ones faces, in contrast to what happens with unfamiliar individuals.

Differential effects of faces and words in cognitive control in older adults with and without major depressive disorder: An emotional Stroop task study

Aging and major depressive disorders have been associated with impaired cognitive control. These deficits are also influenced by the affective valence and by the type of stimulus processed. Using an emotional Stroop task, the current study aims to examine cognitive control deficits and their association with emotion regulation in depression and the influence of the type of stimulus (words and faces) in this association. A total of 26 older patients with a major depressive disorder (MDD) (19 women; age range: 65-84 years) and 26 older healthy controls (18 women; age range: 65-80 years) participated in the study. The results showed that MDD individuals presented greater Stroop effects than their healthy controls and an absence of the conflict adaptation effect defined as a reduction of the influence of irrelevant stimulus dimensions after incongruent trials. Additionally, our results also showed that the processing of emotional words in depressed participants is more automatic than the processing of emotional faces. These findings suggest that older depressed individuals have greater difficulty in recognizing affective facial expressions than older healthy controls, while the over-learned behavior of word reading greatly reduces differences in the performance of the emotional Stroop task between groups (MDD and healthy controls).