Figure 1.

Illustration of the different ERP components recorded in a face-oddball task, in which participants have to detect as quickly as possible the appearance of a target “emotional sad” face among a train of frequent neutral faces by clicking on a button. The P100 component, recorded around 100 ms, refers to the visual perceptive analysis of the stimulus, and can be modulated through attention by different mechanisms such as complexity or motivation. The N170 component is a bilateral occipito-temporal negativity, recorded around 170 ms that refers to the structural encoding of facial information in order to generate a representation of the observed face in short-term memory. The N2b/P3a is a bipolar complex, obtained by subtracting the activity recorded for frequent stimuli from the one obtained for targets, with a posterior negativity recorded around 250 ms, referring to the allocation of attentional resources, while the frontal P3a is more sensitive to stimulus novelty. This complex is functionally seen as the switch of attention needed to process something new appearing in the environment. Finally, the P3b component is a parietal activity indexing pre-motor response stages that shows that the facial representation created in short-term memory for frequent faces has been updated, so that a behavioral motor response may be prepared.

Note: Adapted with permission from Maurage et al⁹⁴ © 2009 Canadian Medical Association and Maurage et al. Electrophysiological correlates of the disrupted processing of anger in alcoholism. Int J Psychophysiol. 2008:70(1):50–62.⁹⁵ Copyright © 2008 Elsevier Inc.

Abbreviation: ERP, event-related potentials.