Although depressed mood is a normal occurrence in response to adversity in all individuals, what distinguishes those who are vulnerable to major depressive disorder (MDD) is their inability to effectively regulate negative mood when it arises. Investigating the neural underpinnings of adaptive emotion regulation and the extent to which such processes are compromised in MDD may be helpful in understanding the pathophysiology of depression. We report results from a functional magnetic resonance imaging study demonstrating left-lateralized activation in the prefrontal cortex (PFC) when downregulating negative affect in nondepressed individuals, whereas depressed individuals showed bilateral PFC activation. Furthermore, during an effortful affective reappraisal task, nondepressed individuals showed an inverse relationship between activation in left ventrolateral PFC and the amygdala that is mediated by the ventromedial PFC (VMPFC). No such relationship was found for depressed individuals, who instead show a positive association between VMPFC and amygdala. Pupil dilation data suggest that those depressed patients who expend more effort to reappraise negative stimuli are characterized by accentuated activation in the amygdala, insula, and thalamus, whereas nondepressed individuals exhibit the opposite pattern. These findings indicate that a key feature underlying the pathophysiology of major depression is the counterproductive engagement of right prefrontal cortex and the lack of engagement of left lateral-ventromedial prefrontal circuitry important for the downregulation of amygdala responses to negative stimuli.
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BACKGROUND: Two core characteristics of pathologic fear are its rapid onset and resistance to cognitive regulation. We hypothesized that activation of the amygdala early in the presentation of fear-relevant visual stimuli would distinguish phobics from nonphobics.
METHODS: Chronometry of amygdala activation to phobia-relevant pictures was assessed in 13 spider phobics and 14 nonphobics using functional magnetic resonance imaging (fMRI).
RESULTS: Blood oxygen level-dependent (BOLD) responses in the amygdala early in picture processing consistently differentiated between phobic and nonphobic subjects, as well as between phobogenic and nonphobogenic stimuli among phobics. Furthermore, amygdalar BOLD responses associated with timing but not magnitude of activation predicted affective responses to phobogenic stimuli. Computational modeling procedures were used to identify patterns of neural activation in the amygdala that could yield the observed BOLD data. These data suggest that phobic responses were characterized by strong but brief amygdala responses, whereas nonphobic responses were weaker and more sustained.
CONCLUSIONS: Results are discussed in the context of the amygdala's role in rapid threat detection and the vigilance-avoidance hypothesis of anxiety. These data highlight the importance of examining the neural substrates of the immediate impact of phobogenic stimuli for understanding pathological fear.
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The ability to share the other's feelings, known as empathy, has recently become the focus of social neuroscience studies. We review converging evidence that empathy with, for example, the pain of another person, activates part of the neural pain network of the empathizer, without first hand pain stimulation to the empathizer's body. The amplitude of empathic brain responses is modulated by the intensity of the displayed emotion, the appraisal of the situation, characteristics of the suffering person such as perceived fairness, and features of the empathizer such as gender or previous experience with pain-inflicting situations. Future studies in the field should address inter-individual differences in empathy, development and plasticity of the empathic brain over the life span, and the link between empathy, compassionate motivation, and prosocial behavior.
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In this article, we consider whether facial expressions of emotion relate in theoretically interesting ways to personal adjustment. We first consider the conceptual benefits of this line of inquiry. Then, to anticipate why brief samples of emotional behavior should relate to personal adjustment, we review evidence indicating that facial expressions of emotion correspond to intrapersonal processes and social outcomes. We then review studies showing that facial expressions relate in theoretically significant ways to adjustment after the death of a spouse, in long-term relationships, and in the context of chronic psychological disorders.
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Although individuals experience embarrassment as an unpleasant, negative emotion, the authors argue that expressions of embarrassment serve vital social functions, signaling the embarrassed individual's prosociality and fostering trust. Extending past research on embarrassment as a nonverbal apology and appeasement gesture, the authors demonstrate that observers recognize the expression of embarrassment as a signal of prosociality and commitment to social relationships. In turn, observers respond with affiliative behaviors toward the signaler, including greater trust and desire to affiliate with the embarrassed individual. Five studies tested these hypotheses and ruled out alternative explanations. Study 1 demonstrated that individuals who are more embarrassable also reported greater prosociality and behaved more generously than their less embarrassable counterparts. Results of Studies 2-5 revealed that observers rated embarrassed targets as being more prosocial and less antisocial relative to targets who displayed either a different emotion or no emotion. In addition, observers were more willing to give resources and express a desire to affiliate with these targets, and these effects were mediated by perceptions of the targets as prosocial.
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The LASS theory proposes that Language and Situated Simulation both play central roles in conceptual processing. Depending on stimuli and task conditions, different mixtures of language and simulation occur. When a word is processed in a conceptual task, it first activates other linguistic forms, such as word associates. More slowly, the word activates a situated simulation to represent its meaning in neural systems for perception, action, and mental states. An fMRI experiment tested the LASS account. In a first scanning session, participants performed the property generation task to provide a measure of conceptual processing. In a second scanning session a week later, participants performed two localizer tasks measuring word association and situated simulation. Conjunction analyses supported predictions of the LASS theory. Activations early in conceptual processing overlapped with activations for word association. Activations late in conceptual processing overlapped with activations for situation generation. These results, along with others in the literature, indicate that conceptual processing uses multiple representations, not one. Furthermore, researchers must be careful drawing conclusions about conceptual processing, given that different paradigms are likely to produce different mixtures of language and simulation. Whereas some paradigms produce high levels of linguistic processing and low levels of simulation, other paradigms produce the opposite pattern.
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Previous research indicates that drug motivational systems are instantiated in structures that process information related to incentive, motivational drive, memorial, motor/habit, craving, and cognitive control processing. The present research tests the hypothesis that activity in such systems will be powerfully affected by the combination of drug anticipation and drug withdrawal. Event-related fMRI was used to examine activation in response to a preinfusion warning cue in two experimental sessions that manipulated withdrawal status. Significant cue-induced effects were seen in the caudate, ventral anterior nucleus of the thalamus, the insula, subcallosal gyrus, nucleus accumbens, and anterior cingulate. These results suggest that withdrawal and nicotine anticipation produce (1) different motor preparatory and inhibitory response processing and (2) different craving related processing.
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This study examined neural activation during the experience of compassion, an emotion that orients people toward vulnerable others and prompts caregiving, and pride, a self-focused emotion that signals individual strength and heightened status. Functional magnetic resonance images (fMRI) were acquired as participants viewed 55 s continuous sequences of slides to induce either compassion or pride, presented in alternation with sequences of neutral slides. Emotion self-report data were collected after each slide condition within the fMRI scanner. Compassion induction was associated with activation in the midbrain periaqueductal gray (PAG), a region that is activated during pain and the perception of others’ pain, and that has been implicated in parental nurturance behaviors. Pride induction engaged the posterior medial cortex, a region that has been associated with self-referent processing. Self-reports of compassion experience were correlated with increased activation in a region near the PAG, and in the right inferior frontal gyrus (IFG). Self-reports of pride experience, in contrast, were correlated with reduced activation in the IFG and the anterior insula. These results provide preliminary evidence towards understanding the neural correlates of important interpersonal dimensions of compassion and pride. Caring (compassion) and self-focus (pride) may represent core appraisals that differentiate the response profiles of many emotions.
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Regional modulation of the level of cortical neurotransmitters in the brain would serve as a new functional brain mapping technique to interrogate the neurochemical actions of the brain. We investigated the utility of the application of low-intensity, pulsed sonication of focused ultrasound (FUS) to the brain to modulate the extracellular level of dopamine (DA) and serotonin (5-HT). FUS was delivered to the thalamic areas of rats, and extracellular DA and 5-HT were sampled from the frontal lobe using the microdialysis technique. The concentration changes of the sampled DA and 5-HT were measured through high-performance liquid chromatography. We observed a significant increase of the extracellular concentrations of DA and 5-HT in the FUS-treated group as compared with those in the unsonicated group. Our results provide the first direct evidence that FUS sonication alters the level of extracellular concentration of these monoamine neurotransmitters and has a potential modulatory effect on their local release, uptake, or degradation. Our findings suggest that the pulsed application of FUS offers new perspectives for a possible noninvasive modulation of neurotransmitters and may have diagnostic as well as therapeutic implications for DA/5-HT-mediated neurological and psychiatric disorders. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 232–240, 2011
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Attention to internal bodily sensations is a core feature of mindfulness meditation. Previous studies have not detected differences in interoceptive accuracy between meditators and nonmeditators on heartbeat detection and perception tasks. We compared differences in respiratory interoceptive accuracy between meditators and nonmeditators in the ability to detect and discriminate respiratory resistive loads and sustain accurate perception of respiratory tidal volume during nondistracted and distracted conditions. Groups did not differ in overall performance on the detection and discrimination tasks; however, meditators were more accurate in discriminating the resistive load with the lowest ceiling effect. Meditators were also more accurate during the nondistracted tracking task at a lag time of 1 s following the breath. Results provide initial support for the notion that meditators have greater respiratory interoceptive accuracy compared to nonmeditators.
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<p>Two hundred twenty-five chronic pain patients were studied following training in mindfulness meditation. Large and significant overall improvements were recorded post-intervention in physical and psychological status. These gains were maintained at follow-up in the majority of subjects. Follow-up times ranged from 2.5-48 months. Status on the McUill Melzack Pain Rating Index (PRI). however, tended to revert to preintervention levels following the intervention. Most subjects reported a high degree of adherence with the meditation techniques, maintenance of improved status over time, and a high degree of importance attributed to the training program. We conclude that such training can have long-term benefit for chronic pain patients.</p>
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Uncontrollable anxious thought characterizes a number of emotional disorders. Little is known, however, about the cognitive mechanisms that underlie the ability to control these thoughts. The present study investigated the extent to which two well-characterized executive control processes--working memory and inhibition--are engaged when an individual attempts to control worry. Participants completed a concurrent assessment of these processes while attempting to control personally-relevant worried and neutral thoughts. To examine the specificity of these effects to attempts to control worry, versus a residual "depletion" effect of having previously engaged in worry, a subset of participants completed the assessment without instructions to control their worried or neutral thoughts. Attempts to control worry engaged working memory and inhibition to a greater extent than did attempts to control neutral thought. This increased engagement was not explained solely by anxious affect, nor was it significantly associated with trait worry. Engagement did not differ by group, suggesting that executive control depletion by worry cannot be dismissed as an alternative explanation of these findings. These results highlight working memory and inhibition as potentially valuable constructs for deepening our understanding of the nature and treatment of worry and its control.
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High vs. low scorers on the Beck Depression Inventory (BDI) were compared on measures of resting EEG activation asymmetry from frontal and parietal brain regions. Depressed subjects showed greater relative right frontal activation compared with nondepressed subjects. Parietal asymmetry did not distinguish between the groups. These data support the hypothesis of right hemisphere hyperactivation in the frontal region of depressed individuals and are consistent with the growing body of literature which suggests that the left and right frontal regions may be differentially specialized for particular positive and negative affects.
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We assessed whether resting anterior asymmetry would discriminate individual differences in repressive-defensive coping styles. In 2 sessions, resting electroencephalogram was recorded from female adults during 8 60-s baselines. Subjects were classified as repressors or nonrepressors on the basis of scores on the Marlowe-Crowne Social Desirability Scale (MC), the State-Trait Anxiety Inventory (STAI), and the Beck Depression Inventory (BDI). In midfrontal and lateral frontal sites, repressors demonstrated relative left hemisphere activation when compared with other groups. The MC, but not the STAI or the BDI, contributed unique variance to frontal asymmetry. Relative left frontal activation may be linked to a self-enhancing regulatory style that promotes lowered risk for psychopathology.
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Individuals differ dramatically in the quality and intensity of their response to affectively evocative stimuli. On the basis of prior theory and research, we hypothesized that these individual differences are related to variation in activation of the left and right frontal brain regions. We recorded baseline brain electrical activity from subjects on two occasions 3 weeks apart. Immediately following the second recording, subjects were exposed to brief positive and negative emotional film clips. For subjects whose frontal asymmetry was stable across the 3-week period, greater left frontal activation was associated with reports of more intense positive affect in response to the positive films, whereas greater right frontal activation was associated with more intense reports of negative affect in response to the negative film clips. The methodological and theoretical implications of these data are discussed.
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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.
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The influence of approach and avoidance tendencies on affect, reasoning, and behavior has attracted substantial interest from researchers across various areas of psychology. Currently, frontal electroencephalographic (EEG) asymmetry in favor of left prefrontal regions is assumed to reflect the propensity to respond with approach-related tendencies. To test this hypothesis, we recorded resting EEG in 18 subjects, who separately performed a verbal memory task under three incentive conditions (neutral, reward, and punishment). Using a source-localization technique, we found that higher task-independent alpha2 (10.5-12 Hz) activity within left dorsolateral prefrontal and medial orbitofrontal regions was associated with stronger bias to respond to reward-related cues. Left prefrontal resting activity accounted for 54.8% of the variance in reward bias. These findings not only confirm that frontal EEG asymmetry modulates the propensity to engage in appetitively motivated behavior, but also provide anatomical details about the underlying brain systems.
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Examined whether certain features of infant temperament might be related to individual differences in the asymmetry of resting frontal activation. EEG was recorded from the left and right frontal and parietal scalp regions of 13 normal 10-month-old infants. Infant behavior was then observed during a brief period of maternal separation. Those infants who cried in response to maternal separation showed greater right frontal activation during the preceding baseline period compared with infants who did not cry. Frontal activation asymmetry may be a state-independent marker for individual differences in threshold of reactivity to stressful events and vulnerability to particular emotions.
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<p>It is well known that the eating patterns that restrain chronic dieters (restrained eaters) can be disinhibited by anxiety, which in turn has been associated with relative right frontal brain activity in independent electroencephalographic (EEG) studies. Combining these two lines of evidence, the authors tested the hypothesis that chronic restrained eating is associated with relative right frontal asymmetry. Resting anterior brain asymmetry and self-reported measures of anxiety and depression were collected in 23 restrained and 32 unrestrained eaters. As hypothesized, groups differed in tonic frontal activity, with restrained eaters showing more relative right frontal activity. Furthermore, relative right frontal activity was associated with greater self-reported restraint. Right-sided prefrontal asymmetry may thus represent a diathesis associated with increased vulnerability toward restrained eating.</p>
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