Benoit Brisson

The relation between attentional control and visual working memory (vWM) has previously been studied with transcranial magnetic stimulation (TMS). For example, it has been shown that rhythmic TMS (rhTMS) can enhance attentional control and, consequently, vWM performance, by boosting prefrontal theta rhythm power. However, it remains unclear if the rhTMS protocol used to improve attentional control for neutral valence distractors can do the same for emotional distractors. Moreover, attentional control can be applied in different ways, either by amplifying relevant stimulus representation or by inhibiting distractor processing. In this study, we used rhTMS to increase theta power over the left dorsolateral prefrontal cortex in 19 healthy participants during a visual change-detection task. Auditory distractors with neutral and angry prosodies were heard during the task. Electroencephalography was used to measure theta power, contralateral delay activity, which indexes visual item maintenance, and the auditory P2, which indexes distractor processing. rhTMS boosted theta power and improved vWM accuracy compared to the sham condition. Theta boost was associated with lower emotional distractor processing, but not better maintenance. Our results indicate that the mechanism for attentional control of emotional auditory distractors in the vWM context is based on inhibition rather than amplification of relevant items.

Apparent race of a face impacts processing efficiency, typically leading to an own-race advantage. For instance, own-race facial expressions are more accurately recognized, and their intensity better appraised, compared to other-race faces. Furthermore, these effects appear susceptible to implicit bias. Here, we aimed to better understand impacts of race and implicit racial bias on facial expression processing by looking at automatic and nonautomatic expression processing stages. To this end, scalp electroencephalography was recorded off a group of White participants while they completed a psychological refractory period dual-task paradigm in which they viewed neutral or fearful White (i.e. own-race) and Black (i.e. other-race) faces. Results showed that, irrespective of race, early perceptual expression processing indexed by the N170 event-related potential was independent of central attention resources and racial attitudes. On the other hand, later emotional content evaluation indexed by the late positive potential (LPP) was dependent on central resources. Furthermore, negative attitudes toward Black individuals amplified LPP emotional response to White (vs. Black) faces irrespective of central attention resources. Thus, it seems it is racial bias, more than race per se, that impacts facial expression processing, but this effect only manifests itself during later semantic processing of facial expression content.

Top–down processes allow the selection and prioritization of information by limiting attentional capture by distractors, and these mechanisms depend on task demands such as working memory (WM) load. However, bottom–up processes give salient stimuli a stronger neuronal representation and provoke attentional capture. The aim of this study was to examine the effect of salient nociceptive stimuli on WM while manipulating task demands. Twenty-one healthy participants performed a change detection task during which they had to determine whether 2 successive visual arrays were different or the same. Task demands were modulated by manipulating the WM load (set size included 2 or 4 objects to recall) and by the correspondence between the 2 successive visual arrays (change vs no change). Innocuous stimuli (control) or nociceptive stimuli (distractors) were delivered during the delay period between the 2 visual arrays. Contralateral delay activity and laser-evoked potentials were recorded to examine neural markers of visual WM and nociceptive processes. Nociceptive stimuli decreased WM performance depending on task demands (all P < 0.05). Moreover, compared with control stimuli, nociceptive stimuli abolished the increase in contralateral delay activity amplitude for set size 4 vs set size 2 (P = 0.04). Consistent with these results, laser-evoked potential amplitude was not decreased when task demands were high (P = 0.5). These findings indicate that WM may shield cognition from nociceptive stimuli, but nociceptive stimuli disrupt WM and alter task performance when cognitive resources become insufficient to process all task-relevant information.

Human behavior is framed by several social structures. In the present study, we focus on two of the most important determinants of social structures: social norms and political orientation. Social norms are implicit models of shared expectations about how people should behave in different social contexts. Although humans are very sensitive to violations in social norms, there are important individual differences in our sensitivity to these violations. The second concept this study focuses on is political orientation that is define by a continuum from left (liberal) to right (conservative). Individual political orientation has been found to be related to various individual traits, such as cognitive style or sensitivity to negative stimuli. Here, we propose to study the relation between sensitivity to social norm violation and political orientation. Participants completed a task presenting scenarios with different degrees of social norm violation and a questionnaire to measure their political opinions on economic and identity issues. Using hierarchical regressions, we show that individual differences in sensitivity to social norm violation are partly explained by political orientation, and more precisely by the identity axis. The more individuals have right-oriented political opinions, the more they are sensitive to social norm violation, even when multiple demographics variables are considered. Our results suggest that political orientation, especially according to identity issues, is a significant factor of individual differences in social norm processing.

When two tasks, Task 1 and Task 2, are conducted in close temporal proximity and a separate speeded response is required for each target (T1 and T2), T2 report performance decreases as a function of its temporal proximity to T1. This so-called psychological refractory period (PRP) effect on T2 processing is largely assumed to reflect interference from T1 response selection on T2 response selection. However, interference on early perceptual processing of T2 has been observed in a modified paradigm, which required changes in visual-spatial attention, sensory modality, task modality, and response modality across targets. The goal of the present study was to investigate the possibility of early perceptual interference by systematically and iteratively removing each of these possible non perceptual confounds, in a series of four experiments. To assess T2 visual memory consolidation success, T2 was presented for a varying duration and immediately masked. T2 report accuracy, which was taken as a measure of perceptual—encoding or consolidation—success, decreased across all experimental control conditions as T1–T2 onset proximity increased. We argue that our results, in light of previous studies, show that central processing of a first target, responsible for the classical PRP effect, also interferes with early perceptual processing of a second target. We end with a discussion of broader implications for psychological refractory period and attentional blink effects.

Rapid and accurate processing of potential social threats is paramount to social thriving, and provides a clear evolutionary advantage. Though automatic processing of facial expressions has been assumed for some time, some researchers now question the extent to which this is the case. Here, we provide electrophysiological data from a psychological refractory period (PRP) dual-task paradigm in which participants had to decide whether a target face exhibited a neutral or fearful expression, as overlap with a concurrent auditory tone categorization task was experimentally manipulated. Specifically, we focused on four event-related potentials (ERP) linked to emotional face processing, covering distinct processing stages and topography: the early posterior negativity (EPN), early frontal positivity (EFP), late positive potential (LPP), and also the face-sensitive N170. As expected, there was an emotion modulation of each ERP. Most importantly, there was a significant attenuation of this emotional response proportional to the degree of task overlap for each component, except the N170. In fact, when the central overlap was greatest, this emotion-specific amplitude was statistically null for the EFP and LPP, and only marginally different from zero for the EPN. N170 emotion modulation was, on the other hand, unaffected by central overlap. Thus, our results show that emotion-specific ERPs for three out of four processing stages—i.e., perceptual encoding (EPN), emotion detection (EFP), or content evaluation (LPP)—are attenuated and even eliminated by central resource scarcity. Models assuming automatic processing should be revised to account for these results.

There is an ongoing debate in the literature about whether facial emotion perception is carried automatically-that is, without effort or attentional resources. While it is generally accepted that spatial attention is necessary for the perception of emotional facial expressions, the picture is less clear for central attention. Using the bubbles method, we provide results that were obtained by measuring the effect of the psychological refractory period on diagnostic information for the basic facial expressions. Based on previous findings that linked spatial attention with processing of the eyes and of high spatial frequencies in the visual periphery, we hypothesized that reliance on the eyes might decrease when central resources were monopolized by a difficult prioritized auditory task. Central load led to a marked decrease in left eye utilization that was generalized across emotions; on the contrary, utilization of the mouth was unaffected by central load. Thus, processing of the left eye might be nonautomatic, and processing of the mouth might be automatic. Interestingly, we also observed a reduction in reliance on the left side of the face under central load that was accompanied by a commensurate increase in reliance on the right side of the face. We end with a discussion of how hemispheric asymmetries might account for these peculiar findings.

In asymptomatic multiple-concussion athletes, studies evidenced long-term impairments in psychomotor speed, motor sequence learning, and cognitive control processes, as indexed by the Error Negativity (Ne), also commonly referred to as the Error-related Negativity (ERN). In healthy controls, motor sequence learning during a Serial Reaction Time (SRT) task is associated with an increase in Ne/ERN amplitude. The objective of this paper is to investigate whether concussion effects on cognitive control are associated with sequence learning changes in asymptomatic multi-concussion athletes. Thirty-seven athletes (18 nonconcussed; 19 concussed) completed a SRT task during which continuous electroencephalographic (EEG) activity was recorded. Ne/ERN amplitude modulation from early to late learning blocks of the task was measured. Median reaction times (RTs) were computed to assess psychomotor speed and motor sequence learning. Psychomotor speed was significantly reduced in concussed athletes. Accentuated Ne/ERN amplitude from early to late learning blocks significantly correlated with motor sequence learning in nonconcussed athletes. In contrast, Ne/ERN amplitude was found to decrease significantly with task progression in concussed athletes who nonetheless achieved normal motor sequence learning. Multiple concussions detrimentally affect psychomotor speed. Unlike nonconcussed athletes, motor sequence learning in multi-concussion athletes was not associated with Ne/ERN amplitude modulation, indicating that cognitive control processes do not centrally contribute to learning of a motor sequence after repeated concussions.