Andrew J. Tomarken

Individual differences in anterior brain asymmetry and fundamental dimensions of emotion.

This research assessed whether individual differences in anterior brain asymmetry are linked to differences in basic dimensions of emotion. In each of 2 experimental sessions, separated by 3 weeks, resting electroencephalogram (EEG) activity was recorded from female adults during 8 60-s baselines. Mean alpha power asymmetry across both sessions was extracted in mid-frontal and anterior temporal sites. Across both regions, groups demonstrating stable and extreme relative left anterior activation reported increased generalized positive affect (PA) and decreased generalized negative affect (NA) compared with groups demonstrating stable and extreme relative right anterior activation. Additional correlational analyses revealed robust relations between anterior asymmetry and PA and NA, particularly among subjects who demonstrated stable patterns of EEG activation over time. Anterior asymmetry was unrelated to individual differences in generalized reactivity.

Resting Frontal Brain Asymmetry Predicts Affective Responses to Films

This article assessed whether resting electroencephalographic (EEG) asymmetry in anterior regions of the brain can predict affective responses to emotion elicitors. Baseline EEG was recorded from 32 female adults, after which Ss viewed film clips preselected to elicit positive or negative affect. Resting alpha power asymmetry in the frontal region significantly predicted self-reported global negative affect in response to clips and predicted the difference between global positive and negative affect. Analyses of discrete emotions revealed a strong relation between frontal asymmetry and fear responses to films. Effects were independent of Ss mood ratings at the time at which baseline EEG was measured. Resting anterior asymmetry may be a state-independent index of the individuals predisposition to respond affectively.

While a phobic waits: regional brain electrical and autonomic activity in social phobics during anticipation of public speaking

BACKGROUND Recent studies have highlighted the role of right-sided anterior temporal and prefrontal activation during anxiety, yet no study has been performed with social phobics that assesses regional brain and autonomic function. This study compared electroencephalograms (EEGs) and autonomic activity in social phobics and controls while they anticipated making a public speech. METHODS Electroencephalograms from 14 scalp locations, heart rate, and blood pressure were recorded while 18 DSM-IV social phobics and 10 controls anticipated making a public speech, as well as immediately after the speech was made. Self-reports of anxiety and affect were also obtained. RESULTS Phobics showed a significantly greater increase in anxiety and negative affect during the anticipation condition compared with controls. Heart rate was elevated in the phobics relative to the controls in most conditions. Phobics showed a marked increase in right-sided activation in the anterior temporal and lateral prefrontal scalp regions. These heart rate and EEG changes together accounted for > 48% of the variance in the increase in negative affect during the anticipation phase. CONCLUSIONS These findings support the hypothesis of right-sided anterior cortical activation during anxiety and indicate that the combination of EEG and heart rate changes during anticipation account for substantial variance in reported negative affect.

Fear-Relevant Selective Associations and Covariation Bias

Three experiments used an illusory correlation paradigm to assess the effects of fear on the perception of the covariation between fear-relevant stimuli and shock. In Experiment 1, high- and low-fear women were exposed to 72 trials during each of which a fear-relevant (snake or spider) or fear-irrelevant (mushroom and flower) slide was followed by a shock, a tone, or nothing. Although the relation between slide types and outcomes was random, high-fear subjects markedly overestimated the contingency between feared slides and shock. Experiment 2 showed that this bias was due to the aversive, rather than more generally salient, features of shock. Low-fear subjects demonstrated biases equivalent to those of high-fear subjects only when the base rate of shock was increased from 33% to 50% in Experiment 3. It is concluded that fear may be linked to biases that serve to confirm fear. The relevance of the present findings to preparedness theory is also discussed.

Individual differences in repressive-defensiveness predict basal salivary cortisol levels.

Prior studies assessing the relation between negative affective traits and cortisol have yielded inconsistent results. Two studies assessed the relation between individual differences in repressive-defensiveness and basal salivary cortisol levels. Experiment 1 assessed midafternoon salivary cortisol levels in men classified as repressors, high-anxious, or low-anxious. In Experiment 2, more rigorous controls were applied as salivary cortisol levels in women and men were assessed at 3 times of day on 3 separate days. In both studies, as hypothesized, repressors and high-anxious participants demonstrated higher basal cortisol levels than low-anxious participants. These findings suggest that both heightened distress and the inhibition of distress may be independently linked to relative elevations in cortisol. Also discussed is the possible mediational role of individual differences in responsivity to, or mobilization for, uncertainty or change.

Frontal brain asymmetry and immune function

The relation between brain activity and the immune system was evaluated by assessing immune responses in 20 healthy women who manifested extreme differences in the asymmetry of frontal cortex activation. One group showed extreme and stable left frontal activation; the other group showed extreme and stable right frontal activation. As predicted, women with extreme right frontal activation had significantly lower levels of natural killer cell activity (at effector:target cell ratios of 33:1 and 11:1) than did left frontally activated individuals. This difference did not extend to two other immune measures, lymphocyte proliferation and T-cell subsets. However, higher immunoglobulin levels of the M class were observed in the right frontal group. In this study, the immune patterns could not be accounted for by plasma cortisol levels, anxiety- and depression-related symptomatology, or recent health histories. These findings support the hypothesis that there is a specific association between frontal brain asymmetry and certain immune responses.

Effects of parental involvement in behavioral weight loss therapy for preadolescents

To examine the effects of parental involvement and family environment on weight loss in obese preadolescents, 40 dyads, consisting of an overweight parent and an overweight 9- to 13-year-old child, were assigned to parent-plus-child (n=16) or child-only (n=15) behavioral treatment groups or a waiting list control group (n=9). While children and parents in both treatment groups received complete written lessons, only children and parents in the parent-plus-child group also attended treatment sessions. Children in both treatment groups lost a significant amount of weight during treatment and maintained their losses through the 1-year follow-up period. In contrast, children in the control group gained a significant amount of weight by the 3-month follow-up. Dyads in the parent-plus-child group showed lower attrition, equivalent child weight reduction and maintenance, and better parental weight loss maintenance than dyads in the child-only group. These results and others obtained via self-report measures and intradyad correlations of weight change indicate that the family environment may play a very important role in treatment outcome achieved by behavioral weight loss therapy for preadolescents.

Resting frontal brain activity: linkages to maternal depression and socio-economic status among adolescents

We tested the prediction that resting frontal brain asymmetry would be a marker of vulnerability for depression among adolescents. Baseline electroencephalographic (EEG) activity was recorded from 12 to 14-year-old adolescents whose mothers had a history of depression (high risk group) and whose mothers were lifetime-free of axis I psychopathology (low risk group). High risk adolescents demonstrated the hypothesized pattern of relative left frontal hypo-activity on alpha-band measures. Such effects were specific to the mid-frontal region and generally consistent across reference montages. Socio-economic status (SES) also predicted alpha asymmetry. When the effects of SES and risk status were jointly assessed, SES contributed unique variance to the prediction of frontal brain asymmetry. The implications of the observed relations among maternal depression, SES, and frontal brain asymmetry are discussed.

Task‐dependent changes in frontal brain asymmetry: Effects of incentive cues, outcome expectancies, and motor responses

The current study was designed to clarify the psychological functions most closely associated with frontal brain asymmetry. Electroencephalography (EEG) was recorded from 60 participants while they performed a delayed reaction time (RT) task that included manipulations of incentive, expectancy, and response. Significant alpha asymmetry effects were reflected in topographic differences across anterior EEG sites. Variations in monetary incentives resulted in parametric changes in anterior frontal alpha asymmetry. Manipulations of outcome expectancies were related to mid-frontal EEG changes that differed for men and women. Varied response requirements were related to central asymmetry patterns. Taken together, the findings suggest that regionally specific patterns of frontal asymmetry are functionally related to particular aspects of approach-withdrawal tendencies involved in the temporal guidance and regulation of goal-directed behavior.

The effects of safety behaviors on health anxiety: An experimental investigation

The present study examined the extent to which safety behaviors exacerbate symptoms of hypochondriasis (severe health anxiety). Participants were randomized into a safety behavior (n=30) or control condition (n=30). After a baseline period, participants in the safety behavior condition spent one week actively engaging in a clinically representative array of health-related safety behaviors on a daily basis, followed by a second week-long baseline period. Participants in the control condition monitored their normal use of safety behaviors. Compared to control participants, those in the safety behavior condition reported significantly greater increases in health anxiety, hypochondriacal beliefs, contamination fear, and avoidant responses to health-related behavioral tasks after the safety behavior manipulation. In contrast, general anxiety symptoms did not significantly differ between the two groups as a function of the manipulation. Mediational analyses were consistent with the hypothesis that changes in the frequency of health-related thoughts mediated the effects of the experimental manipulation on health anxiety. These findings suggest that safety behaviors are associated with increases in health anxiety, perhaps by fostering catastrophic thoughts about health. The implications of these findings for the conceptualization of hypochondriasis as an anxiety disorder are discussed.