Rebecca J. Compton

Paying attention to emotion: An fMRI investigation of cognitive and emotional Stroop tasks

In this research, we investigated the degree to which brain systems involved in ignoring emotionally salient information differ from those involved in ignoring nonemotional information. The design allowed examination of regional brain activity, using fMRI during color-word and emotional Stroop tasks. Twelve participants indicated the color of words while ignoring word meaning in conditions in which neutral words were contrasted to emotionally negative, emotionally positive, and incongruent color words. Dorsolateral frontal lobe activity was increased by both negative and incongruent color words, indicating a common system for maintaining an attentional set in the presence of salient distractors. In posterior regions of the brain, activity depended on the nature of the information to be ignored. Ignoring color-incongruent words increased left parietal activity and decreased parahippocampal gyrus activity, whereas ignoring negative emotional words increased bilateral occipito-temporal activity and decreased amygdala activity. The results indicate that emotion and attention are intimately related via a network of regions that monitor for salient information, maintain attention on the task, suppress irrelevant information, and select appropriate responses.

Ability to disengage attention predicts negative affect

This investigation addresses the hypothesis that negative affect is associated with decreased ability to shift attention to a new focus. Thirty-nine participants completed a covert attentional orienting task and then viewed a distressing film clip. Mood was measured by self-report at the beginning and end of the session. Correlations between attentional orienting performance and self-reported mood indicated that participants with greater response time costs on invalidly cued trials reported more negative affect in response to the film. These results support the hypothesis that negative affect is associated with a slowness to disengage attention.

Alpha power is influenced by performance errors

Error commission evokes changes in event-related potentials, autonomic nervous system activity, and behavior, presumably reflecting the operation of a cognitive control network. Here we test the hypothesis that errors lead to increased cortical arousal, measurable as changes in electroencephalogram (EEG) alpha band power. Participants performed a Stroop task while EEG was recorded. Following correct responses, alpha power increased and then decreased in a quadratic pattern, implying transient mental disengagement during the intertrial interval. This trend was absent following errors, which elicited significantly less alpha power than correct trials. Moreover, post-error alpha power was a better predictor of individual differences in post-error slowing than the error-related negativity (ERN), whereas the ERN was a better predictor of post-error accuracy than alpha power. These findings imply that changes in cortical arousal play a unique role in modulating post-error behavior.

Responding to threat: hemispheric asymmetries and interhemispheric division of input.

This investigation examined how hemispheric asymmetry and interhemispheric processing contribute to attentional biases toward emotional information. Participants (n = 88) named the color of lateralized squares presented concurrently with neutral, positive, or threatening words. A left-hemisphere advantage in color naming was reduced when distractors were emotional, suggesting right-hemisphere priming by emotional stimuli. Furthermore, the advantage of dividing the word and color across visual fields was increased for emotion words when they were frequently presented, indicating a strategic use of interhemispheric division of labor to reduce the distracting effect of emotional words. Finally, participants with high levels of anxious apprehension were most likely to make use of this interhemispheric processing strategy, supporting a processing efficiency theory of cognitive function in anxiety.

Error-Monitoring Ability Predicts Daily Stress Regulation

This study examined whether individual differences in error-related self-regulation predict emotion regulation in daily life, as suggested by a common-systems view of cognitive and emotional self-regulation. Participants (N = 47) completed a Stroop task, from which error-related brain potentials and behavioral measures of error correction were computed. Participants subsequently reported on daily stressors and anxiety over a 2-week period. As predicted by the common-systems view, a physiological marker of error monitoring and a behavioral measure of error correction predicted emotion regulation in daily life. Specifically, participants higher in cognitive control, as assessed neurally and behaviorally, were less reactive to stress in daily life. The results support the notion that cognitive control and emotion regulation depend on common or interacting systems.

Error Detection and Posterror Behavior in Depressed Undergraduates

This study examined the influence of depression on error-monitoring and behavioral compensation after errors, two important aspects of cognitive control. Undergraduates differing in self-reported depression levels completed a modified Stroop task while error-related scalp potentials were recorded. Behaviorally, participants with higher depression scores were disproportionately slower and less accurate after errors in a task condition that included negative emotional words. Physiological results indicated that the amplitudes of the error-related negativity (ERN) and error positivity (Pe), two indices of error detection, were not correlated with depression score. ERN amplitudes predicted behavioral slowdown after errors, but only among more depressed participants in the negative-word condition. Together, the results imply that depression is associated not with an error detection deficit, but rather with alterations in subsequent performance changes, once errors have been identified.

Practice makes a hemisphere perfect: The advantage of interhemispheric recruitment is eliminated with practice.

As task performance improves with practice, oftentimes fewer brain areas are recruited to aid in processing. However, relatively little research has investigated how practice affects interactions between brain regions. Given prior work indicating that interhemispheric division of processing is most advantageous when task demands are high, we predicted that interactions between the cerebral hemispheres would be less advantageous after practice than before practice. This hypothesis was confirmed by reanalysis of data from two previously published studies. Practice reduced (1) the degree to which interhemispheric interaction facilitated performance for two letter-matching tasks (Experiment 1), and (2) the extent to which interhemispheric interaction reduced interference in a global-local perception task (Experiment 2). These findings illustrate the dynamic nature of neural recruitment in response to changing task demands.

Anxiety and Error Monitoring: Increased Error Sensitivity or Altered Expectations?.

This study tested the prediction that the error-related negativity (ERN), a physiological measure of error monitoring, would be enhanced in anxious individuals, particularly in conditions with threatening cues. Participants made gender judgments about faces whose expressions were either happy, angry, or neutral. Replicating prior studies, midline scalp negativities were greater following errors than following correct responses. In addition, state anxiety interacted with facial expression to predict ERN amplitudes. Counter to predictions, participants high in state anxiety displayed smaller ERNs for angry-face blocks and larger ERNs for happy-face blocks, compared to less anxious participants. These results are inconsistent with the simple notion that anxiety enhances error sensitivity globally. Rather, we interpret the findings within an expectancy violation framework, in which anxious participants have altered expectations for success and failure in the context of happy and angry facial cues, with greater ERN amplitudes when expectations are violated.

Association between positive affect and attentional shifting

This investigation tested the hypothesis that individuals low in positive affect are slower to shift attention from one focus to another. Ninety-six participants completed a self-report mood questionnaire and a standard attentional orienting task. Results indicated a significant correlation between cue validity effects and self-reported positive affect, such that individuals low in positive affect were relatively faster to respond to validly-cued targets and slower to respond to invalidly-cued targets, compared to individuals high in positive affect. Negative affect, psychometrically separated from positive affect by a principal components analysis, was unrelated to attentional orienting but was correlated with generalized alerting effects of cues. The main results are interpreted as supporting decreased cognitive flexibility in states of low positive affect.

Cognitive control in the intertrial interval: Evidence from EEG alpha power

This study used electroencephalogram (EEG) power spectrum analyses to characterize neural activity during the intertrial interval, a period during which online cognitive adjustments in response to errors or conflict are thought to occur. EEG alpha power was quantified as an inverse index of cerebral activity during the period between each response and the next stimulus in a Stroop task. Alpha power was significantly reduced following error responses compared to correct responses, indicating greater cerebral activity following errors. Reduced alpha power was also observed following Stroop conflict trials compared to no-conflict trials, suggesting that conflict engages processes of mental adjustment. Finally, hemispheric differences in alpha power during the intertrial interval supported the complementary roles of the left and right hemispheres in behavioral activation and inhibition.