The relation between electroencephalogram asymmetry and attention biases to threat at baseline and under stress.

Electroencephalogram (EEG) asymmetry in the alpha frequency band has been implicated in emotion processing and broad approach-withdrawal motivation systems. Questions remain regarding the cognitive mechanisms that may help elucidate the observed links between EEG asymmetry and patterns of socioemotional functioning. The current study observed frontal EEG asymmetry patterns at rest and under social threat among young adults (N=45, M=21.1 years). Asymmetries were, in turn, associated with performance on an emotion-face dot-probe attention bias task. Attention biases to threat have been implicated as potential causal mechanisms in anxiety and social withdrawal. Frontal EEG asymmetry at baseline did not predict attention bias patterns to angry or happy faces. However, increases in right frontal alpha asymmetry from baseline to the stressful speech condition were associated with vigilance to angry faces and avoidance of happy faces. The findings may reflect individual differences in the pattern of response (approach or withdrawal) with the introduction of a mild stressor. Comparison analyses with frontal beta asymmetry and parietal alpha asymmetry did not find similar patterns. Thus, the data may reflect the unique role of frontal regions, particularly the dorsolateral prefrontal cortex, in cognitive control and threat detection, coupled with ruminative processes associated with alpha activity.