Anxiety and defensiveness: individual differences in affective startle modulation

Anxious individuals selectively attend to threatening information, and defensiveness may influence the experience and expression of anxiety. Fifty-eight undergraduates scoring high and low on measures of anxiety and defensiveness viewed pleasant, neutral, and unpleasant pictures. Acoustic startle probes were presented 60, 240, or 2,000 ms after picture onset. At 60 ms and 240 ms, repressors (low anxiety, high defensiveness) showed weaker blinks during both pleasant and unpleasant compared to neutral pictures, suggesting enhanced early attention to affective stimuli, regardless of valence. At 2,000 ms, high-anxious but not low anxious participants showed potentiated startle responses during unpleasant compared to pleasant pictures. Although this result replicated previous research on anxiety and valence modulation of startle, exploratory analyses suggested that the valence effect was restricted to trait anxious individuals tending toward a defensive coping style. Across probe conditions, defensiveness was associated with heightened startle reactivity independent of self-reported anxiety and foreground stimulus characteristics.

Affective ratings and startle modulation in people with nonclinical depression

This study tested predictions based on the emotion context insensitivity (ECI) hypothesis of Rottenberg, Gross, and Gotlib (2005) that a nonclinical sample of people with depressive symptoms would show reduced responses to both positive and negative stimuli relative to people without depression and would show an enhanced response to novelty. Seventy individuals completed diagnostic questionnaires, made ratings of 21 affectively valenced pictures, and then viewed the same 21 pictures and 21 novel pictures while startle blink responses were recorded from electromyographic activity of the orbicularis oculi. People with scores on the Beck Depression Inventory (BDI; Beck, Ward, Mendelson, Mock, & Erbaugh, 1961) indicative of depression demonstrated a lack of affective startle modulation compared to the nondepression group. For all participants, the startle response was larger for novel pictures than for previously viewed pictures, but scores on the BDI were not related to response to novelty. Taken together, the results suggest that nonclinical depression is associated with a lack of affective modulation of startle, as has been shown for clinical depression.     

Age-related affective modulation of the startle eyeblink response: older adults startle most when viewing positive pictures

Previous studies reveal age by valence interactions in attention and memory, such that older adults focus relatively more on positive and relatively less on negative stimuli than younger adults. In the current study, eyeblink startle response was used to measure differences in emotional reactivity to images that were equally arousing to both age groups. Viewing positive and negative pictures from the International Affective Picture System had opposite effects on startle modulation for older and younger adults. Younger adults showed the typical startle blink pattern, with potentiated startle when viewing negative pictures compared to positive pictures. Older adults, on the other hand, showed the opposite pattern, with potentiated startle when viewing positive pictures compared to viewing negative and neutral pictures. Potential underlying mechanisms for this interaction are evaluated. This pattern suggests that, compared with younger adults, older adults are more likely to spontaneously suppress responses to negative stimuli and process positive stimuli more deeply.     

The neuropsychological profile in unipolar depression

There is a wealth of empirical data pertaining to the issue of neuropsychological impairment in depression. However, a coherent and comprehensive framework for understanding the disorder remains elusive. This review will briefly consider some of the important issues on which recent research has focused. It would be premature to derive firm conclusions in an area characterized by considerable confusion, so the aim of this review is to highlight the key areas that must be addressed. Three distinct questions are considered. The first concerns the neuropsychological specificity of the deficits associated with depression; whether they represent selective deficits or a more general profile of impairment. The second question is to determine how cognitive deficits might relate to clinical and demographic factors, including symptom severity, hospitalization, medication and ageing. Finally, a comprehensive theory of depression must also relate impairments to neuropathology, and evidence is now available from imaging studies that have attempted to elucidate neural substrates of neuropsychological deficits.     

Individual differences in rate of affect change: studies in affective chronometry

Three studies explored individual differences in rate of affect change. Participants watched affect-inducing videos and reported their affect twice in 20 min. Individual differences in rate of affect change emerged independently of initial affect intensity and stress appraisals, revealing 2 affect-change profiles. Positive affect augmenters (extraverts, emotionally stable participants, and those with high negative mood regulation expectancies) showed slow rates of positive and rapid rates of negative affect decay. Negative affect augmenters (introverts, neurotics, and participants with low negative mood regulation expectancies) showed slow rates of negative and rapid rates of positive affect decay. These findings expand the literature on affective style, have adaptational implications, and highlight future research directions.     

Dimensions of perfectionism in unipolar depression

We tested the hypothesis that self-oriented perfectionism, other-oriented perfectionism, and socially prescribed perfectionism are related differentially to unipolar depression. The Multidimensional Perfectionism Scale was administered along with measures of depression and anxiety to 22 depressed patients, 22 matched normal control subjects, and 13 anxiety patients. It was found that the depressed patients had higher levels of self-oriented perfectionism than did either the psychiatric or normal control subjects. In addition, depressed patients and anxious patients reported higher levels of socially prescribed perfectionism than did the normal control subjects. The results suggest that various dimensions of perfectionism may play an important role in clinical depression.     

Trait emotions and affective modulation of the startle eyeblink: on the unique relationship of trait anger

We examined relationships among individual differences in trait emotions and the emotion-modulated startle-eyeblink response. In particular, we examined the extent to which trait anger, which is negative in valence, would be associated with a pattern of approach motivation in startle eyeblink responses to appetitive stimuli. Self-reported trait emotions were compared with emotion-modulated startle eyeblink responses to auditory probes during appetitive, aversive, and neutral pictures. Results revealed that trait anger, enjoyment, and surprise were each associated with greater blink inhibition to appetitive pictures, indicating an approach motivational response. No other trait emotions were associated with startle eyeblink responses to appetitive or aversive pictures. These results support the idea that trait anger, although experienced as a negative emotion, is associated with an approach-related motivational response to appetitive stimuli at basic, reflexive levels of processing.     

Phasic affective modulation of creativity

Thus far, it has been shown that positive compared to negative mood increases creativity, for instance, as measured by performance in the remote associate task, where participants are asked to find the common remote associate for three clue words (e.g., RABBIT CLOUD MILK solution word WHITE). The present experiments show that very brief variations in affect, lasting for only a few seconds and changing from trial to trial within participants, are sufficient to modulate creativity in that task, presumably by modulating the breadth of semantic spread. Using word valence of remote associates themselves (Experiment 1), and consonant and dissonant chords (Experiment 2) as affect inductions, it was observed that brief positive compared to negative affect increased creative performance. This evidence extends the affect-modulation hypothesis to a temporal micro-level.     

Affective individual differences and startle reflex modulation

Potentiation of startle has been demonstrated in experimentally produced aversive emotional states, and clinical reports suggest that potentiated startle may be associated with fear or anxiety. To test the generalizability of startle potentiation across a variety of emotional states as well as its sensitivity to individual differences in fearfulness, the acoustic startle response of 17 high- and 15 low-fear adult subjects was assessed during fear, anger, joy, sadness, pleasant relaxation, and neutral imagery. Startle responses were larger in all aversive affective states than during pleasant imagery. This effect was enhanced among high fear subjects, although followup testing indicated that other affective individual differences (depression and anger) may also be related to increased potentiation of startle in negative affect. Startle latency was reduced during high- rather than low-arousal imagery but was unaffected by emotional valence.     

Comorbidity of unipolar depression: I. Major depression with dysthymia

The degree of current and lifetime comorbidity between major depressive disorder (MDD) and dysthymia (DY) was examined in large community samples of older adolescents (n = 1,710) and adults (n = 2,060). DY was highly comorbid with MDD (lifetime odds ratio of 3.4 for adolescents and 1.6 for adults) and was more likely to precede than to follow MDD, especially in persons who became depressed early in life. MDD was by far the more frequent form of depression: Approximately 80% of the depressed persons experienced only MDD, 10% experienced only DY, and 10% experienced both MDD and DY. The large number of persons who had became depressed twice experienced MDD in the 2nd episode, regardless of the nature of the 1st depression. History of depression was associated with a greater probability for other mental disorders in both adolescents and adults; however, the rates of comorbidity for MDD did not differ from rates for DY or for both MDD and DY.     

Load-dependent modulation of affective picture processing

Because of the biological significance of emotional stimuli, their processing is considered largely automatic. In the study reported herein, we tested the alternative hypothesis—namely, that the processing of emotional stimuli requires some level of attention. Our experiments utilized highly negative and arousing visual stimuli comprising mutilated bodies. All experiments employed a single task, which consisted of determining whether two peripheral bars were like oriented or not, thereby eliminating potential task-difference confounds that may have contaminated prior studies. Our results revealed that task-irrelevant unpleasant images slowed reaction time during the performance of the main task. Such interference was modulated by task difficulty as well as by alcohol consumption, showing that the processing of emotional visual stimuli is not immune to attentional manipulations. These results suggest that it is essential to utilize attentional manipulations that more fully consume attentional resources in order to demonstrate that the processing of emotional stimuli is resource limited.     

Modeling unipolar depression as a chaotic process

This study inspected the deterministic structure of unipolar depression. Two women self-monitored sadness hourly 10 times a day for 6 months. One woman had a recurrent history of unipolar depression, and the other did not. Data were analyzed by visual inspection, examination of the Fourier transforms of the time plots, and the correlation dimension. Results suggested that in addition to a strong periodic component that existed only within the depressed subject's mood time series, a low-dimensional chaotic process might have been operating. In the nondepressed control subject, no such periodicity or process could be identified. The findings support maladaptive deterministic theories of mood disorders and have implications for the assessment of unipolar depression.     

Automatic and effortful information processing in unipolar major depression

The present study investigated attentional dysfunction in patients with recurrent unipolar major depression in a visual search paradigm. The attentional aspects of automatic and effortful information processing were examined. The general hypothesis was that patients with unipolar major depression would have more problems with tasks that require effortful information processing than with tasks that require only automatic information processing. A task requiring effortful processing attracts attention, is more demanding, and is instruction-driven. A task that is automatically processed does not invoke attention, is less demanding, and is stimulus-driven. The results showed that the patient group needed significantly longer reaction times on the tasks requiring more effortful information processing than the control group, but there were no significant differences between groups on tasks requiring automatic information processing. Thus it seems as if the depressed patients show an impaired profile as a function of the degree of effort a task requires.     

Generation of stress in the course of unipolar depression.

The effect of stressful events on depression has been amply demonstrated, but the opposite relation is also important. I examined event occurrence over 1 year in 14 women with unipolar depression who were compared with demographically matched groups of women with bipolar disorder (n = 11), chronic medical illness (n = 13), or no illness or disorder (n = 22). Interview assessments of life events, severity, and independence of occurrence confirmed the hypothesis that unipolar women were exposed to more stress than the normal women, had significantly more interpersonal event stress than all others, and tended to have more dependent events than the others. The implication is that unipolar women by their symptoms, behaviors, characteristics, and social context generate stressful conditions, primarily interpersonal, that have the potential for contributing to the cycle of symptoms and stress that create chronic or intermittent depression.     

Stress modulation of cognitive and affective processes

This review summarizes the major discussion points of a symposium on stress modulation of cognitive and affective processes, which was held during the 2010 workshop on the neurobiology of stress (Boulder, CO, USA). The four discussants addressed a number of specific cognitive and affective factors that are modulated by exposure to acute or repeated stress. Dr David Morilak discussed the effects of various repeated stress situations on cognitive flexibility, as assessed with a rodent model of attentional set-shifting task, and how performance on slightly different aspects of this test is modulated by different prefrontal regions through monoaminergic neurotransmission. Dr Serge Campeau summarized the findings of several studies exploring a number of factors and brain regions that regulate habituation of various autonomic and neuroendocrine responses to repeated audiogenic stress exposures. Dr Kerry Ressler discussed a body of work exploring the modulation and extinction of fear memories in rodents and humans, especially focusing on the role of key neurotransmitter systems including excitatory amino acids and brain-derived neurotrophic factor. Dr Israel Liberzon presented recent results on human decision-making processes in response to exogenous glucocorticoid hormone administration. Overall, these discussions are casting a wider framework on the cognitive/affective processes that are distinctly regulated by the experience of stress and some of the brain regions and neurotransmitter systems associated with these effects.