Andero Uusberg

EEG alpha and cortical inhibition in affective attention.

Recent progress in cognitive neuroscience suggests that alpha activity may reflect selective cortical inhibition involved in signal amplification, rather than neural idling. Unfortunately, these theoretical advances remain largely ignored in affective neuroscience. To address this limitation the present paper proposes a novel research avenue aimed at using alpha to elucidate cortical inhibitory mechanisms involved in affective processes. The proposal is illustrated by developing inhibitory accounts of affective attention and affective tuning phenomena. The emergent predictions were tested using event-related perturbations from 73 students evaluating affective and nonaffective aspects of five types of emotional images. The results revealed that upper alpha power was increased by affective content in general and aversive stimuli in particular from 350 ms at posterior and from 575 ms at central sites. The evaluation task interacted with affective content only at a liberal statistical significance level in late posterior alpha. These results are generally in line with the proposed inhibitory accounts of affective attention and tuning, although the evidence is preliminary rather than conclusive. As confirmation of functional origins of alpha in affect remains beyond the scope of a single study, this paper aims to inspire further extrapolation of the inhibitory account of alpha within affective neuroscience.

Emotional modulation of attention affects time perception: evidence from event-related potentials

Emotional effects on human time perception are generally attributed to arousal speeding up or slowing down the internal clock. The aim of the present study is to investigate the less frequently considered role of attention as an alternative mediator of these effects with the help of event-related potentials (ERPs). Participants produced short intervals (0.9, 1.5, 2.7, and 3.3s) while viewing high arousal images with pleasant and unpleasant contents in comparison to neutral images. Behavioral results revealed that durations were overproduced for the 0.9s interval whereas, for 2.7 and 3.3s intervals, underproduction was observed. The effect of affective valence was present for the shorter durations and decreased as the target intervals became longer. More specifically, the durations for unpleasant images were less overproduced in the 0.9s intervals, and for the 1.5s trials, durations for unpleasant images were slightly underproduced, compared to pleasant images, which were overproduced. The analysis of different ERP components suggests possible attention processes related to the timing of affective images in addition to changes in pacemaker speed. Early Posterior Negativity (EPN) was larger for positive than for negative images, indicating valence-specific differences in activation of early attention mechanisms. Within the early P1 and the Late Positive Potential (LPP) components, both pleasant and unpleasant stimuli exhibited equal affective modulation. Contingent Negative Variation (CNV) remained independent of both timing performance and affective modulation. This pattern suggests that both pleasant and unpleasant stimuli enhanced arousal and captured attention, but the latter effect was more pronounced for pleasant stimuli. The valence-specificity of affective attention revealed by ERPs combined with behavioral timing results suggests that attention processes indeed contribute to emotion-induced temporal distortions, especially for longer target intervals.

Using distraction to regulate emotion: Insights from EEG theta dynamics

Distraction is a powerful and widely-used emotion regulation strategy. Although distraction regulates emotion sooner than other cognitive strategies (Thiruchselvam, Blechert, Sheppes, Rydstrom, & Gross, 2011), it is not yet clear whether it is capable of blocking the earliest stages of emotion generation. To address this issue, we capitalized on the excellent temporal resolution of EEG by focusing on occipital theta dynamics which were associated with distinct stages of visual processing of emotional stimuli. Individually defined theta band dynamics were extracted from a previously published EEG dataset (Thiruchselvam et al., 2011) in which participants attended to unpleasant (and neutral) images or regulated emotion using distraction and reappraisal. Results revealed two peaks within early theta power increase, both of which were increased by emotional stimuli. Distraction did not affect theta power during an early peak (150-350 ms), but did successfully decrease activity in a second peak (350-550 ms). These results suggest that although distraction acts relatively early in the emotion-generative trajectory, it does not block fast detection of emotional significance. Given that theta dynamics were uncorrelated with Late Positive Potential activity, the present results also encourage researchers to add the occipital theta to the growing toolkit of EEG-based measures of emotion regulation.

Personality cannot be predicted from the power of resting state EEG.

In the present study we asked whether it is possible to decode personality traits from resting state EEG data. EEG was recorded from a large sample of subjects (n = 289) who had answered questionnaires measuring personality trait scores of the five dimensions as well as the 10 subordinate aspects of the Big Five. Machine learning algorithms were used to build a classifier to predict each personality trait from power spectra of the resting state EEG data. The results indicate that the five dimensions as well as their subordinate aspects could not be predicted from the resting state EEG data. Finally, to demonstrate that this result is not due to systematic algorithmic or implementation mistakes the same methods were used to successfully classify whether the subject had eyes open or closed. These results indicate that the extraction of personality traits from the power spectra of resting state EEG is extremely noisy, if possible at all.

Links between self-reported and laboratory behavioral impulsivity.

A major problem in the research considering impulsivity is the lack of mutual understanding on how to measure and define impulsivity. Our study examined the relationship between self-reported impulsivity, behavioral excitatory and inhibitory processes and time perception. Impulsivity--fast, premature, thoughtless or disinhibited behavior--was assessed in 58 normal, healthy participants (30 men, mean age 21.9 years). Self-reported impulsivity as measured by Adaptive and Maladaptive Impulsivity Scale (AMIS) and behavioral excitatory and inhibitory processes as measured by Stop Signal Task were not directly related. Time perception, measured by the retrospective Time Estimation Task, was related to both. The length of the perceived time interval was positively correlated to AMIS Disinhibition subscale and negatively to several Stop Signal Task parameters. The longer subjects perceived the duration to last, the higher was their score on Disinhibition scale and the faster were their reactive responses in the Stop Signal Task. In summary our findings support the idea of cognitive tempo as a possible mechanism underlying impulsive behavior.

Unintentionality of affective attention across visual processing stages.

Affective attention involves bottom-up perceptual selection that prioritizes motivationally significant stimuli. To clarify the extent to which this process is automatic, we investigated the dependence of affective attention on the intention to process emotional meaning. Affective attention was manipulated by presenting affective images with variable arousal and intentionality by requiring participants to make affective and non-affective evaluations. Polytomous rather than binary decisions were required from the participants in order to elicit relatively deep emotional processing. The temporal dynamics of prioritized processing were assessed using early posterior negativity (EPN, 175–300 ms) as well as P3-like (P3, 300–500 ms) and slow wave (SW, 500–1500 ms) portions of the late positive potential. All analyzed components were differentially sensitive to stimulus categories suggesting that they indeed reflect distinct stages of motivational significance encoding. The intention to perceive emotional meaning had no effect on EPN, an additive effect on P3, and an interactive effect on SW. We concluded that affective attention went from completely unintentional during the EPN to partially unintentional during P3 and SW where top-down signals, respectively, complemented and modulated bottom-up differences in stimulus prioritization. The findings were interpreted in light of two-stage models of visual perception by associating the EPN with large-capacity initial relevance detection and the P3 as well as SW with capacity-limited consolidation and elaboration of affective stimuli.

Approach-avoidance activation without anterior asymmetry.

Occasionally, the expected effects of approach-avoidance motivation on anterior EEG alpha asymmetry fail to emerge, particularly in studies using affective picture stimuli. These null findings have been explained by insufficient motivational intensity of, and/or overshadowing interindividual variability within the responses to emotional pictures. These explanations were systematically tested using data from 70 students watching 5 types of affective pictures ranging from very pleasant to unpleasant. The stimulus categories reliably modulated self-reports as well as the amplitude of late positive potential, an ERP component reflecting orienting toward motivationally significant stimuli. The stimuli did not, however, induce expected asymmetry effects either for the sample or individual participants. Even while systematic stimulus-dependent individual differences emerged in self-reports as well as LPP amplitudes, the asymmetry variability was dominated by stimulus-independent interindividual variability. Taken together with previous findings, these results suggest that under some circumstances anterior asymmetry may not be an inevitable consequence of core affect. Instead, state asymmetry shifts may be overpowered by stable trait asymmetry differences and/or stimulus-independent yet situation-dependent interindividual variability, possibly caused by processes such as emotion regulation or anxious apprehension.

Identity and Self-Control: Linking Identity-Value and Process Models of Self-Control

Self-control is crucial for achieving academic and occupational success, financial security, and mental and physical health (Moffitt et al., 2011; Moffitt, Poulton, & Caspi, 2013). Although self-control may be defined in many ways, we view self-control as the adjudication of a conflict between two action impulses, one driven by a goal that is of shorter-term value and one driven by a goal that is of more enduring value (Duckworth & Gross, 2014). Successful self-control entails resolving this conflict in favor of the more enduringly valued goal (see Figure 1). Because self-control is thought to be more malleable than other important predictors of positive life outcomes, such as IQ and socioeconomic status, it has generated intense interest among scientists and policy-makers alike as a target for intervention (Duckworth & Seligman, 2005; Moffitt et al., 2011). To design effective interventions, however, researchers need a comprehensive yet parsimonious understanding of the psychological and neural mechanisms underlying self-control. One such model is the identity-value model (IVM; Berkman, Livingston, & Kahn, this issue). The IVM offers a thoughtful conceptualization of selfcontrol that draws on research in social and cognitive psychology and neuroscience to provide a framework both for understanding basic processes and for identifying interventions. For these reasons, we welcome the IVM and hope it will have a major impact on self-control research. In this commentary we first briefly review the IVM. We then describe the process model of self-control and indicate how the IVM can be contextualized within this broader framework. Finally, we show how integrating these approaches suggests promising new avenues for identity-based interventions.

Bending time: The role of affective appraisal in time perception.

Affective states are known to distort time perception, but it remains unclear why and how they do so. To test whether appraisal processes involved in affect may play a role in temporal distortions, we investigated bisection behavior during experimental events with varying appraisal values along three dimensions: goal relevance (high vs. low), goal type (approach vs. avoid), and goal congruence (conducive vs. obstructive). Forty female participants performed an incentive-compatible gambling task attempting to accumulate wins and avoid losses of small amounts of chocolate. On each trial, a prechoice stimulus first announced whether a win, a loss, or no change was available. Participants then made a choice that ostensibly determined the outcome of the trial, which was communicated by a postchoice stimulus. Participants also made temporal bisection decisions indicating whether the presentation durations of pre- and postchoice stimuli (which varied between 200, 320, 440, 560, 680, and 800 ms) were closer to a previously learned short (200 ms) or long (800 ms) standard. We analyzed appraisal effects on psychometric bisection point, response speed, and drift diffusion parameter variance using custom regression contrasts. Subjective durations were found to be lengthened by high goal relevance, conducive goal congruence, and approach goal type. Analysis of diffusion parameters suggested that these results reflected appraisal-related shifts in duration perception rather than in subsequent decision-making. These findings encourage further research into the possibility that temporal distortions are among the cognitive changes triggered by appraisal processes during affective states.

Attention biases in preoccupation with body image: an ERP study of the role of social comparison and automaticity when processing body size

Appearance-related attention biases are thought to contribute to body image disturbances. We investigated how preoccupation with body image is associated with attention biases to body size, focusing on the role of social comparison processes and automaticity. Thirty-six women varying on self-reported preoccupation compared their actual body size to size-modified images of either themselves or a figure-matched peer. Amplification of earlier (N170, P2) and later (P3, LPP) ERP components recorded under low vs. high concurrent working memory load were analyzed. Women with high preoccupation exhibited an earlier bias to larger bodies of both self and peer. During later processing stages, they exhibited a stronger bias to enlarged as well as reduced self-images and a lack of sensitivity to size-modifications of the peer-image. Working memory load did not affect these biases systematically. Current findings suggest that preoccupation with body image involves an earlier attention bias to weight increase cues and later over-engagement with own figure.