First impressions on face trustworthiness across ages: Evidence from a cross-sectional study.

The present study aimed to explore how the sense of trustworthiness is influenced by age and gender. Participants were to judge computer-generated faces for trustworthiness in two different experimental conditions according to the orientation of the virtual stimuli: canonical (i.e. upright) and inverted (i.e. upside down). Experimental stimuli were presented very briefly and were specifically selected to look: trustworthy, untrustworthy or neutral. The results showed that the tendency to evaluate faces as trustworthy was modulated by both age and gender. In particular, young participants were more prone to judge faces as trustworthy than adult, elderly and child participants. In turn, males were more prone to evaluate faces as trustworthy than females, but this difference was not found among children.

" The times they aren't a-changin' " rTMS does not affect basic mechanisms of temporal discrimination: a pilot study with ERPs.

In time processing, the role of different cortical areas is still under investigation. Event-related potentials (ERPs) represent valuable indices of neural timing mechanisms in the millisecond-to-second domain. We used an interference approach by repetitive TMS (rTMS) on ERPs and behavioral performance to investigate the role of different cortical areas in processing basic temporal information. Ten healthy volunteers were requested to decide whether time intervals between two tones (S1-S2, probe interval) were shorter (800ms), equal to, or longer (1200ms) than a previously listened 1000-ms interval (target interval) and press different buttons accordingly. This task was performed at the baseline and immediately after a 15-min-long train of 1-Hz rTMS delivered over the supplementary motor area, right posterior parietal cortex, right superior temporal gyrus, or an occipital control area. Task accuracy, reaction time, and ERPs during (contingent negative variation, CNV) and after the presentation of probe intervals were analyzed. At the baseline, CNV amplitude was modulated by the duration of the probe interval. RTMS had no significant effect on behavioral or ERP measures. These preliminary data suggest that stimulated cortical areas are less crucially involved than other brain regions (e.g. subcortical structures) in the explicit discrimination of auditory time intervals in the range of hundreds of milliseconds.

Fearful expressions enhance recognition memory: electrophysiological evidence.

Facial expressions play a key role in affective and social behavior. However, the temporal dynamics of the brain responses to emotional faces remain still unclear, in particular an open question is at what stage of face processing expressions might influence encoding and recognition memory. To try and answer this question we recorded the event-related potentials (ERPs) elicited in an old/new recognition task. A novel aspect of the present design was that whereas faces were presented during the study phase with either a happy, fearful or neutral expression, they were always neutral during the memory retrieval task. The ERP results showed three main findings: An enhanced early fronto-central positivity for faces encoded as fearful, both during the study and the retrieval phase. During encoding subsequent memory (Dm effect) was influenced by emotion. At retrieval the early components P100 and N170 were modulated by the emotional expression of the face at the encoding phase. Finally, the later ERP components related to recognition memory were modulated by the previously encoded facial expressions. Overall, these results suggest that face recognition is modulated by top-down influences from brain areas associated with emotional memory, enhancing encoding and retrieval in particular for fearful emotional expressions.

When memory meets beauty: Insights from event-related potentials.

Facial attractiveness plays a key role in human social and affective behavior. To study the time course of the neural processing of attractiveness and its influence on recognition memory we investigated the event-related potentials (ERPs) elicited in an old/new recognition task in response to faces with a neutral expression that, at encoding, were rated for their attractiveness. Highly attractive faces elicited a specific early positive-going component on frontal sites; in addition, with respect to less attractive faces, they elicited larger later components related to structural encoding and recognition memory. All in all, our results show that facial attractiveness, independently from facial expression, modulates face processing throughout all stages from encoding to retrieval.