Adolescents' propensity for risk-taking and reward-seeking behaviors suggests a heightened sensitivity for reward, reflected by greater feedback-related activity changes in reward circuitry (e.g., nucleus accumbens), and/or a lower sensitivity to potential harm reflected by weaker feedback-related activity changes in avoidance circuitry (e.g., amygdala) relative to adults. Responses of nucleus accumbens and amygdala to valenced outcomes (reward receipt and reward omission) were assayed using an event-related functional magnetic resonance imaging procedure paired with a monetary reward task in 14 adults and 16 adolescents. Bilateral amygdala and nucleus accumbens showed significantly greater activation when winning than when failing to win in both groups. Group comparisons revealed stronger activation of left nucleus accumbens by adolescents, and of left amygdala by adults. When examining responses to reward receipts and to reward omissions separately, the most robust group difference was within the amygdala during reward omission. The reduction of the fMRI BOLD signal in the amygdala in response to reward omission was larger for adults than for adolescents. Correlations showed a close link between negative emotion and amygdala decreased BOLD signal in adults, and between positive emotion and nucleus accumbens activation in adolescents. Overall, these findings support the notion that the signal differences between positive and negative outcomes involve the nucleus accumbens more in adolescents than in adults, and the amygdala more in adults than in adolescents. These developmental differences, if replicated, may have important implications for the development of early-onset disorders of emotion and motivation.
Introduction: Anxiety disorders in adults involve aberrant processing of emotional information that is hypothesized to reflect perturbations in the amygdala. This study examines the relationship between face-emotion recognition and anxiety in a sample of children and adolescents participating in a brain-imaging study of amygdala structure and function. Methods: This study recruited 15 children and adolescents with ongoing anxiety disorders and 11 psychiatrically healthy comparisons group-matched on age, gender, and IQ. Face-emotion recognition was assessed using the Diagnostic Analysis of Nonverbal Accuracy Scale (DANVA). Results: Children and adolescents with anxiety disorders exhibited significantly poorer performance on the face-emotion recognition task compared to healthy controls (z = 2.2; p < 0.05). This difference was found only for expressions posed by adults but not children. Discussion: Reduced accuracy on a face-emotion recognition test is consistent with perturbed amygdala function in pediatric anxiety disorders. Conclusion: As this study was conducted in a sample undergoing a neuroimaging investigation of amygdala integrity, future analyses will examine associations among amygdala function, clinical anxiety, and face-recognition abilities.
We suggest that the core feature of bipolar disorder (BPD) is marked state fluctuations. The pathophysiology of switches into depressed, irritable, and extreme positive valence states requires study, with the latter deserving particular focus because it represents a pathognomonic feature of BPD in both adults and children. Hypotheses regarding the pathophysiology of pediatric BPD must account for these marked state fluctuations as well as for specific developmental aspects of the illness. These developmental aspects include marked irritability (in addition to euphoria and depression) and very rapid cycles, along with high rates of attention-deficit/hyperactivity disorder. We review research on neural mechanisms underlying positive valence states and state regulation, focusing on those data relevant to BPD and to development. Researchers are beginning to explore the response of manic patients and control subjects to positive affective stimuli, and considerable research in both nonhuman primates and humans has focused on the cortico–limbic–striatal circuits mediating responses to rewarding stimuli. In control subjects, positive affect affects cognition, and data indicate that prefrontal electroencephalogram asymmetry may differ between control subjects with consistently positive affect and those with more negative affect; however, this latter generalization may not apply to adolescents. With regard to the pathophysiology of state switching in pediatric BPD, data in control subjects indicating that attention regulation plays a role in emotion regulation may be germane. In addition, research detailing physiologic and psychological responses to negative emotional stimuli in bipolar patients and control subjects may increase our understanding of the mechanisms underlying both irritability and rapid cycling seen in children with BPD. Potential foci for research on the pathophysiology of pediatric BPD include reactivity to standardized positive and negative emotional stimuli, and the interaction between emotion regulation and attentional processes.
Background. Many changes in social behavior take place during adolescence. Sexuality and romantic interests emerge during this time, and adolescents spend more time with peers and less time with parents and family. While such changes in social behavior have been well documented in the literature, relatively few neurophysiological explanations for these behavioral changes have been presented. Method. In this article we selectively review studies documenting ( a ) the neuronal circuits that are dedicated to the processing of social information; ( b ) the changes in social behavior that take place during adolescence; ( c ) developmental alterations in the adolescent brain; and ( d ) links between the emergence of mood and anxiety disorders in adolescence and changes in brain physiology occurring at that time. Results. The convergence of evidence from this review indicates a relationship between development of brain physiology and developmental changes in social behavior. Specifically, the surge of gonadal steroids at puberty induces changes within the limbic system that alters the emotional attributions applied to social stimuli while the gradual maturation of the prefrontal cortex enables increasingly complex and controlled responses to social information. Conclusions. Observed alterations in adolescent social behavior reflect developmental changes in the brain social information processing network. We further speculate that dysregulation of the social information processing network in this critical period may contribute to the onset of mood and anxiety disorders during adolescence.
Objective: Little is known about neuropsychological and social-cognitive function in patients with pediatric bipolar disorder. Identification of specific deficits and strengths that characterize pediatric bipolar disorder would facilitate advances in diagnosis, treatment, and research on pathophysiology. The purpose of this study was to test the hypothesis that youths with bipolar disorder would perform more poorly than matched healthy comparison subjects on measures of social cognition, motor inhibition, and response flexibility.Method: Forty outpatients with pediatric bipolar disorder and 22 comparison subjects ( no differences in age, gender, and IQ) completed measures of social cognition ( the pragmatic judgment subtest of the Comprehensive Assessment of Spoken Language, facial expression recognition subtests of the Diagnostic Analysis of Nonverbal Accuracy Scale, the oral expression subtest of the Test of Language Competence), inhibition and response flexibility stop and stop-change tasks), and motor inhibition ( continuous performance tasks).Results: Pediatric bipolar disorder patients performed more poorly than comparison subjects on social-cognitive measures ( pragmatic judgment of language, facial expression recognition) and on a task requiring response flexibility. These deficits were present in euthymic patients. Differences between patients and comparison subjects could not be attributed to comorbid attention deficit hyperactivity disorder.Conclusions: Findings of impaired social cognition and response flexibility in youths with pediatric bipolar disorder suggest continuity between pediatric bipolar disorder and adult bipolar disorder. These findings provide a foundation for neurocognitive research designed to identify the neural mechanisms underlying these deficits.
Objective To test the hypothesis that patients with pediatric bipolar disorder (PBPD) would demonstrate impairment relative to diagnosis-free controls of comparable age, gender, and IQ on measures of memory functioning. Method The authors administered a battery of verbal and visuospatial memory tests to 35 outpatients with PBPD and 20 healthy controls who participated as volunteers in this study. Groups did not differ on age, gender, or IQ. Results Consistent with findings in adults with BPD, patients with PBPD performed more poorly than controls on measures of verbal learning/memory and delayed facial recognition memory. Impaired memory was particularly evident in patients with comorbid PBPD/attention-deficit/hyperactivity disorder or acute mood symptoms. Conclusions These findings suggest that deficits in verbal learning and memory, as well as some aspects of visuospatial memory, characterize patients with narrow phenotype PBPD. Further research is needed, however, to clarify the roles of comorbid attention-deficit/hyperactivity disorder and acute mood state in the emergence of these deficits. Given the apparent continuity in memory dysfunction between adult BPD and narrow phenotype PBPD, research aimed at elucidating underlying neural mechanisms for this set of deficits is warranted.
Fear conditioning represents the process by which a neutral stimulus comes to evoke fear following its repeated pairing with an aversive stimulus. Although fear conditioning has long been considered a central pathogenic mechanism in anxiety disorders, studies employing lab-based conditioning paradigms provide inconsistent support for this idea. A quantitative review of 20 such studies, representing fear-learning scores for 453 anxiety patients and 455 healthy controls, was conducted to verify the aggregated result of this literature and to assess the moderating influences of study characteristics. Results point to modest increases in both acquisition of fear learning and conditioned responding during extinction among anxiety patients. Importantly, these patient-control differences are not apparent when looking at discrimination studies alone and primarily emerge from studies employing simple, single-cue paradigms where only danger cues are presented and no inhibition of fear to safety cues is required.
Biased attention to threat represents a key feature of anxiety disorders. This bias is altered by therapeutic or stressful experiences, suggesting that the bias is plastic. Charting on-line behavioral and neurophysiological changes in attention bias may generate insights on the nature of such plasticity. We used an attention-orientation task with threat cites to examine bow healthy individuals alter their response over time to such cites. In Experiments 1 through 3, we established that healthy individuals demonstrate an increased attention bias away from threat over time. For Experiment 3, we used functional magnetic resonance imaging to determine the neural bases for this phenomenon. Gradually increasing attention bias away from threat is associated with increased activation in the occipitotemporal cortex. Examination of plasticity of attention bias with individuals at risk for anxiety disorders way reveal how threatening stimuli come to be categorized differently in this population over time.
We examined neural activations during decision-making using fMRI paired with the wheel of fortune task, a newly developed two-choice decision-making task with probabilistic monetary gains. In particular, we assessed the impact of high-reward/risk events relative to low-reward/risk events on neural activations during choice selection and during reward anticipation. Seventeen healthy adults completed the study. We found, in line with predictions, that (i) the selection phase predominantly recruited regions involved in visuo-spatial attention (occipito-parietal pathway), conflict (anterior cingulate), manipulation of quantities (parietal cortex), and preparation for action (premotor area), whereas the anticipation phase prominently recruited regions engaged in reward processes (ventral striatum); and (ii) high-reward/risk conditions relative to low-reward/risk conditions were associated with a greater neural response in ventral striatum during selection, though not during anticipation. Following an a priori ROI analysis focused on orbitofrontal cortex, we observed orbitofrontal cortex activation (BA 11 and 47) during selection (particularly to high-risk/reward options), and to a more limited degree, during anticipation. These findings support the notion that (1) distinct, although overlapping, pathways subserve the processes of selection and anticipation in a two-choice task of probabilistic monetary reward; (2) taking a risk and awaiting the consequence of a risky decision seem to affect neural activity differently in selection and anticipation; and thus (3) common structures, including the ventral striatum, are modulated differently by risk/reward during selection and anticipation.