Elevated Amygdala Activity Research Articles

Risky decision-making strategies mediate the relationship between amygdala activity and real-world financial savings among individuals from lower income households: A pilot study

Lower financial savings among individuals experiencing adverse social determinants of health (SDoH) increases vulnerabilities during times of crisis. SDoH including low socioeconomic status (low-SES) influence cognitive abilities as well as health and life outcomes that may perpetuate poverty and disparities. Despite evidence suggesting a role for financial growth in minimizing SDoH-related disparities and vulnerabilities, neurobiological mechanisms linked with financial behavior remain to be elucidated. As such, we examined the relationships between brain activity during decision-making (DM), laboratory-based task performance, and money savings behavior. Participants (N = 24, 14 females) from low-SES households (income<$20,000/year) underwent fMRI scanning while performing the Balloon Analogue Risk Task (BART), a DM paradigm probing risky- and strategic-DM processes. Participants also completed self-report instruments characterizing relevant personality characteristics and then engaged in a community outreach financial program where amount of money saved was tracked over a 6-month period. Regarding BART-related brain activity, we observed expected activity in regions implicated in reward and emotional processing including the amygdala. Regarding brain-behavior relationships, we found that laboratory-based BART performance mediated the impact of amygdala activity on real-world behavior. That is, elevated amygdala activity was linked with BART strategic-DM which, in turn, was linked with more money saved after 6 months. In exploratory analyses, this mediation was moderated by emotion-related personality characteristics such that, only individuals reporting lower alexithymia demonstrated a relationship between amygdala activity and savings. These outcomes suggest that DM-related amygdala activity and/or emotion-related personality characteristics may provide utility as an endophenotypic marker of individual’s financial savings behavior.

Journal Digest: Amygdala and ‘Broken Heart’ Syndrome; Digital Intervention and Paranoia Symptoms; Snoring in Children and Brain Development; Impaired Self-Control and Binge Eating Behavior; HS Football and Midlife Mental Health Problems

Journal Digest: Amygdala and ‘Broken Heart’ Syndrome; Digital Intervention and Paranoia Symptoms; Snoring in Children and Brain Development; Impaired Self-Control and Binge Eating Behavior; HS Football and Midlife Mental Health Problems

Elevated Amygdala Activity in Young Adults With Familial Risk for Depression: A Potential Marker of Low Resilience

BackgroundAmygdala overactivity has been frequently observed in patients with depression, as well as in nondepressed relatives of patients with depression. A remaining unanswered question is whether elevated amygdala activity in those with familial risk for depression is related to the presence of subthreshold symptoms or to a trait-level vulnerability for illness. MethodsTo examine this question, functional magnetic resonance imaging data were collected in nondepressed young adults with (family history [FH+]) (n = 27) or without (FH−) (n = 45) a first-degree relative with a history of depression while they viewed images of “looming” or withdrawing stimuli (faces and cars) that varied in salience by virtue of their apparent proximity to the subject. Activation of the amygdala and 2 other regions known to exhibit responses to looming stimuli, the dorsal intraparietal sulcus (DIPS) and ventral premotor cortex (PMv), were measured, as well as levels of resilience, anxiety, and psychotic and depressive symptoms. ResultsCompared with the FH− group, the FH+ group exhibited significantly greater responses of the amygdala, but not the dorsal intraparietal sulcus or ventral premotor cortex, to looming face stimuli. Moreover, amygdala responses in the FH+ group were negatively correlated with levels of resilience and unrelated to levels of subthreshold symptoms of psychopathology. ConclusionsThese findings indicate that elevated amygdala activity in nondepressed young adults with a familial history of depression is more closely linked to poor resilience than to current symptom state.

Sex-dependent associations between maternal prenatal cortisol and child callous-unemotional traits: Findings from the Wirral Child Health and Development Study

BackgroundElevated maternal glucocorticoids during pregnancy may impact on fetal development in a sex-dependent way, leading to increased amygdala activation and increased risk for internalising disorders in females. Based on evidence implicating reduced amygdala activation in callous-unemotional (CU) traits, we predicted that elevated maternal cortisol in pregnancy would be associated with lower CU traits and elevated anxious-depressed symptoms, only in girls. MethodsParticipants were 225 members of a stratified subsample within an epidemiological longitudinal cohort (WCHADS). Salivary cortisol was measured over two days at 32 weeks gestation (on waking, 30-min post-waking and during the evening) and the log of the area under the curve (LogAUC) was calculated as an index of diurnal cortisol. Mothers reported on child CU traits and anxious-depressed symptoms at 2.5, 3.5 and 5.0 years of age. ResultsAs predicted there was a sex of child by cortisol interaction (p < .001) whereby elevated maternal cortisol was associated with lower child CU traits, explaining 25% of the variance, in girls, but not in boys. This effect remained when controlling for relevant confounders and anxious-depressed symptoms. By contrast, elevated maternal cortisol did not predict higher anxious-depressed symptoms in girls. ConclusionsThe study adds to growing evidence for sex-dependent effects of elevated maternal cortisol during pregnancy on early child psychopathology, consistent with mediation by elevated amygdala activation. The conditions under which, in girls, this is associated with heightened responsiveness to others’ distress characteristic of low CU traits, or with increased affective symptoms, require further study.

Association of Neuroimaging Measures of Emotion Processing and Regulation Neural Circuitries With Symptoms of Bipolar Disorder in Offspring at Risk for Bipolar Disorder

Bipolar disorder (BD) is difficult to distinguish from other psychiatric disorders. Neuroimaging studies can identify objective markers of BD risk. To identify neuroimaging measures in emotion processing and regulation neural circuitries and their associations with symptoms specific to youth at risk for BD. This cross-sectional (August 1, 2011, to July 31, 2017) and longitudinal (February 1, 2013, to November 30, 2017) neuroimaging study performed at the University of Pittsburgh Medical Center compared a sample of 31 offspring of parents with BD (OBP) with 28 offspring of comparison parents with non-BD psychopathologies (OCP) and 21 offspring of healthy parents (OHP); OBP, OCP, and OHP were recruited from the Bipolar Offspring Study and the Longitudinal Assessment of Manic Symptoms Study. Group differences in activity and functional connectivity during emotional face processing and n-back task performance in amygdala, dorsolateral and ventrolateral prefrontal cortices (PFC), caudal anterior cingulate cortices (cACC), and rostral anterior cingulate cortices (rACC) neuroimaging measures showing between-group differences and symptom severity (anxiety, affective lability, depression, mania). We hypothesized that elevated amygdala activity and/or lower PFC activity and abnormal amygdala to PFC functional connectivity would distinguish OBP from OCP and OHP, and magnitudes of these abnormalities would positively correlate with elevated symptom severity. We explored associations between changes in neuroimaging and symptom measures over follow-up (mean [SD], 2.9 [1.4] years) in a subset of participants (n = 30). Eighty participants were included (mean [SD] age, 14.2 (2.1) years; 35 female). Twelve neuroimaging measures explained 51% of the variance in the results of neuroimaging measures overall. Of the 12, 9 showed significant main associations of the group; however, after post hoc analyses and Bonferroni corrections, only 7 showed statistically significant associations between groups (corrected P < .05 for all). Of the 7, 2 showed significant relationships with symptoms. Offspring of parents with BD had greater right rACC activity when regulating attention to happy faces vs OCP (mean [SD] difference, 0.744 [0.249]; 95% CI, 0.134-1.354; P = .01), which positively correlated with affective lability severity (ρ = 0.304; uncorrected P = .006). Offspring of parents with BD had greater amygdala to left cACC functional connectivity when regulating attention to fearful faces vs OCP (mean [SD] difference, 0.493 [0.169]; 95% CI, 0.079-0.908; P = .01). Increases in this measure positively correlated with increases in affective lability over follow-up (r = 0.541; P = .003). Greater anterior cingulate cortex activity and functional connectivity during emotion regulation tasks may be specific markers of BD risk. These findings highlight potential neural targets to aid earlier identification of and guide new treatment developments for BD.

Negative Autobiographical Memory in Depression Reflects Elevated Amygdala-Hippocampal Reactivity and Hippocampally Associated Emotion Regulation

BackgroundDysregulated autobiographical recall is observed in major depressive disorder (MDD). However, it is unknown whether people with MDD show abnormalities in memory-, emotion-, and control-related brain systems during reactivity to and regulation of negative autobiographical memories. MethodsWe used functional magnetic resonance imaging to identify neural mechanisms underlying MDD-related emotional responses to negative autobiographical memories and the ability to downregulate these responses using a cognitive regulatory strategy known as reappraisal. We compared currently depressed, medication-free patients with MDD (n = 29) with control participants with no history of depression (n = 23). ResultsRelative to healthy control participants, medication-free MDD patients reported greater negative emotion during recall but relatively intact downregulation success. They also showed elevated amygdala activity and greater amygdala-hippocampal connectivity. This connectivity mediated the effect of MDD on negative emotional experience. When reappraising memories (vs. recalling from an immersed perspective), the MDD and control groups showed comparable recruitment of the prefrontal, parietal, and temporal cortices, and comparable downregulation of the amygdala and anterior hippocampus. However, MDD patients showed greater downregulation of the posterior hippocampus, and the extent of this downregulation predicted successful reduction of negative affect in MDD patients only. ConclusionsThese data suggest amygdala-hippocampal connectivity and posterior hippocampal downregulation as brain mechanisms related to elevated emotional reactivity and atypical emotion regulation in MDD.

Veterans with PTSD demonstrate amygdala hyperactivity while viewing threatening faces: A MEG study

Posttraumatic stress disorder (PTSD) is a major psychiatric disorder that is prevalent in combat veterans. Previous neuroimaging studies have found elevated amygdala activity in PTSD in response to threatening stimuli, but previous work has lacked the temporal specificity to study fast bottom-up fear responses involving the amygdala. Forty-four combat veterans, 28 with PTSD and 16 without, completed psychological testing and then a face-processing task during magnetoencephalography (MEG). The resulting MEG data were pre-processed, transformed into the time-frequency domain, and then imaged using a beamforming approach. We found that veterans with PTSD exhibited significantly stronger oscillatory activity from 50 to 450 ms in the left amygdala compared to veterans without PTSD while processing threatening faces. This group difference was not present while viewing neutral faces. The current study shows that amygdala hyperactivity in response to threatening cues begins quickly in PTSD, which makes theoretical sense as an adaptive bottom-up fear response.

The Limbic System in Youth Depression: Brain Structural and Functional Alterations in Adolescent In-patients with Severe Depression.

Adolescent-onset major depressive disorder (MDD) is associated with an increased risk of recurrent depressive episodes, suicidal behaviors, and psychiatric morbidity throughout the lifespan. The objective of the present study was to investigate brain structural and functional changes in adolescent patients with MDD. Furthermore, we aimed to clarify the influence of early-life stress on brain function and structure. The study investigated adolescent patients with severe MDD (n=20, mean age=16.0, range=15-18 years) and a control sample of matched healthy adolescents (n=21, mean age=16.6, range=15-18 years). Functional MRI data were obtained using a face-matching paradigm to investigate emotion processing. Structural MRI data were analyzed using voxel-based morphometry (VBM). In line with previous studies on adult MDD, adolescent patients showed elevated amygdala activity to negative and reduced amygdala activity to positive emotional stimuli. Furthermore, MDD patients showed smaller hippocampal volumes compared to healthy adolescents. Higher levels of childhood maltreatment were associated with smaller hippocampal volumes in both depressed patients and healthy controls, whereby no associations between amygdala reactivity and childhood maltreatment were found. Our results suggest that hippocampal alterations in youth MDD patients may at least partly be traced back to higher occurrence of early-life adverse experiences. Regarding the strong morphometric impact of childhood maltreatment and its distinctly elevated prevalence in MDD populations, this study provides an alternative explanation for frequently observed limbic structural abnormalities in depressed patients.

Input from the medial geniculate nucleus modulates amygdala encoding of fear memory discrimination.

Generalization of fear can involve abnormal responding to cues that signal safety and is common in people diagnosed with post-traumatic stress disorder. Differential auditory fear conditioning can be used as a tool to measure changes in fear discrimination and generalization. Most prior work in this area has focused on elevated amygdala activity as a critical component underlying generalization. The amygdala receives input from auditory cortex as well as the medial geniculate nucleus (MgN) of the thalamus, and these synapses undergo plastic changes in response to fear conditioning and are major contributors to the formation of memory related to both safe and threatening cues. The requirement for MgN protein synthesis during auditory discrimination and generalization, as well as the role of MgN plasticity in amygdala encoding of discrimination or generalization, have not been directly tested. GluR1 and GluR2 containing AMPA receptors are found at synapses throughout the amygdala and their expression is persistently up-regulated after learning. Some of these receptors are postsynaptic to terminals from MgN neurons. We found that protein synthesis-dependent plasticity in MgN is necessary for elevated freezing to both aversive and safe auditory cues, and that this is accompanied by changes in the expressions of AMPA receptor and synaptic scaffolding proteins (e.g., SHANK) at amygdala synapses. This work contributes to understanding the neural mechanisms underlying increased fear to safety signals after stress.

Amygdala Activity May Predict Future Cardiovascular Events

Back to table of contents Previous article Next article Clinical and Research NewsFull AccessAmygdala Activity May Predict Future Cardiovascular EventsAaron LevinAaron LevinSearch for more papers by this authorPublished Online:20 Apr 2017https://doi.org/10.1176/appi.pn.2017.3b8AbstractResearchers find a biological link between effects of stress on the amygdala and later cardiovascular events.Higher emotional stress as measured by resting metabolic activity of the amygdala is associated with greater risk of subsequent cardiovascular disease events, according to a study published online January 11 in The Lancet. The findings “provide novel insights into the mechanism through which emotional stressors can lead to cardiovascular disease,” wrote researchers led by Ahmed Tawakol, M.D., an associate professor of medicine at Massachusetts General Hospital and Harvard Medical School.Tawakol and colleagues hypothesized that activity in the amygdala in response to stress increases arterial inflammation both directly and by way of activity in bone marrow.“What is novel here is the bridging of multiple areas of research,” said Peter Gianaros, Ph.D., a professor of psychology and psychiatry and director of the Behavioral Neurophysiology Lab at the University of Pittsburgh. Gianaros has also studied the relationship between the amygdala and cardiovascular disease but was not involved with Tawakol’s study.“It builds on threads of prior research that pointed in this direction and makes strong connections with research on the neurobiology of stress as well as with clinical cardiology,” said Gianaros. “Now we have the proof of concept and a vision of the future.”The amygdala is known to be a key component of the brain’s stress network. Past studies in mice suggested that amygdala activity in response to stress accelerates cytokine production and atherosclerosis, but whether the same was true of humans was unknown.Tawakol and colleagues examined data originally derived from cancer screening imaging studies of 293 patients. Using positron emission tomography/computed tomography (PET/CT) scans, they analyzed activity in the amygdala and in bone marrow, as well as arterial inflammation.During the median follow-up of 3.7 years, 22 patients experienced a cardiovascular disease event—including heart attacks, strokes, angina, or other events. Each increase of one standard deviation in resting amygdala activity predicted a 1.6 risk of a cardiovascular event. The results were significant even after adjusting for established cardiovascular risk factors.Greater amygdala activity was also associated with increased bone marrow activity, which the authors said led to increased arterial inflammation followed by cardiovascular disease events.“[T]he brain’s salience network, bone marrow, and arterial inflammation together form an axis that could accelerate the development of cardiovascular disease,” concluded Tawakol and colleagues. “Furthermore, our findings raise the possibility that efforts to attenuate psychosocial stress could produce benefits that extend beyond an improved sense of psychological well-being and could beneficially impact the atherosclerotic milieu.”Clinicians might eventually screen for and treat chronic stress just as they do for other cardiovascular risk factors, they suggested.Realistically, clinical applications are still well down the road, and much needs to be done to move the field forward, said Gianaros.“We’ll need to set norms and thresholds for amygdala activity and see cost reductions in the methods used to assess it,” he said. For instance, it would be helpful to know more about what factors contribute to elevated amygdala activity, how people vary in their appraisal of stressors, and whether the amygdala sensitizes individuals to stressors in the environment or if the increased activity is a result of repeated stressors, he said.“This rigorous study is a good example of how multidisciplinary work can lead to potential breakthroughs or make connections that don’t happen when working in silos,” said Gianaros. ■An abstract of “Relation between resting amygdalar activity and cardiovascular events: a longitudinal and cohort study” can be accessed here. ISSUES NewArchived

Brain mechanisms of anxiety's effects on cognitive control in major depressive disorder.

Adults with major depressive disorder (MDD) demonstrate increased susceptibility to interfering effects of anxiety on cognitive control; although under certain conditions adults with MDD are able to compensate for these effects. The brain mechanisms that may facilitate the ability to compensate for anxiety either via the recruitment of additional cognitive resources or via the regulation of interference from anxiety remain largely unknown. To clarify these mechanisms, we examined the effects of anxiety on brain activity and amygdala-prefrontal functional connectivity in adults diagnosed with MDD. A total of 22 unmedicated adults with MDD and 18 healthy controls (HCs) performed the Tower of London task under conditions designed to induce anxiety, while undergoing a functional magnetic resonance imaging assessment. During the easy condition, the MDD group demonstrated equivalent planning accuracy, longer planning times, elevated amygdala activity and left rostrolateral prefrontal cortex (RLPFC) hyperactivity relative to HCs. Anxiety mediated observed group differences in planning times, as well as differences in amygdala activation, which subsequently mediated observed differences in RLPFC activation. During the easy condition, the MDD group also demonstrated increased negative amygdala-dorsolateral prefrontal cortex (DLPFC) connectivity which correlated with improved planning accuracy. During the hard condition, HCs demonstrated greater DLPFC activation and stronger negative amygdala-DLPFC connectivity, which was unrelated to planning accuracy. Our results suggest that persons with MDD compensate for anxiety-related limbic activation during low-load cognitive tasks by recruiting additional RLPFC activation and through increased inhibitory amygdala-DLPFC communication. Targeting these neural mechanisms directly may improve cognitive functioning in MDD.

Distinct frontal and amygdala correlates of change detection for facial identity and expression.

Recruitment of ‘top-down’ frontal attentional mechanisms is held to support detection of changes in task-relevant stimuli. Fluctuations in intrinsic frontal activity have been shown to impact task performance more generally. Meanwhile, the amygdala has been implicated in ‘bottom-up’ attentional capture by threat. Here, 22 adult human participants took part in a functional magnetic resonance change detection study aimed at investigating the correlates of successful (vs failed) detection of changes in facial identity vs expression. For identity changes, we expected prefrontal recruitment to differentiate ‘hit’ from ‘miss’ trials, in line with previous reports. Meanwhile, we postulated that a different mechanism would support detection of emotionally salient changes. Specifically, elevated amygdala activation was predicted to be associated with successful detection of threat-related changes in expression, over-riding the influence of fluctuations in top-down attention. Our findings revealed that fusiform activity tracked change detection across conditions. Ventrolateral prefrontal cortical activity was uniquely linked to detection of changes in identity not expression, and amygdala activity to detection of changes from neutral to fearful expressions. These results are consistent with distinct mechanisms supporting detection of changes in face identity vs expression, the former potentially reflecting top-down attention, the latter bottom-up attentional capture by stimulus emotional salience.

Elevated amygdala activity during reappraisal anticipation predicts anxiety in avoidant personality disorder

BackgroundAvoidant personality disorder is characterized by pervasive anxiety, fear of criticism, disapproval, and rejection, particularly in anticipation of exposure to social situations. An important but underexplored question concerns whether anxiety in avoidant patients is associated with an impaired ability to engage emotion regulatory strategies in anticipation of and during appraisal of negative social stimuli. MethodsWe examined the use of an adaptive emotion regulation strategy, cognitive reappraisal, in avoidant patients. In addition to assessing individual differences in state and trait anxiety levels, self-reported affect as well as measures of neural activity were compared between 17 avoidant patients and 21 healthy control participants both in anticipation of and during performance of a reappraisal task. ResultsAvoidant patients showed greater state and trait-related anxiety relative to healthy participants. In addition, relative to healthy participants, avoidant patients showed pronounced amygdala hyper-reactivity during reappraisal anticipation, and this hyper-reactivity effect was positively associated with increasing self-reported anxiety levels. LimitationsOur finding of exaggerated amygdala activity during reappraisal anticipation could reflect anxiety about the impending need to reappraise, anxiety about the certainty of an upcoming negative image, or anxiety relating to anticipated scrutiny of task responses by the experimenters. While we believe that all of these possibilities are consistent with the phenomenology of avoidant personality disorder, future research may clarify this ambiguity. ConclusionsThese results suggest that amygdala reactivity in anticipation of receiving negative social information may represent a key component of the neural mechanisms underlying the heightened anxiety present in avoidant patients.

Amygdala perfusion is predicted by its functional connectivity with the ventromedial prefrontal cortex and negative affect.

BackgroundPrevious studies have shown that the activity of the amygdala is elevated in people experiencing clinical and subclinical levels of anxiety and depression (negative affect). It has been proposed that a reduction in inhibitory input to the amygdala from the prefrontal cortex and resultant over-activity of the amygdala underlies this association. Prior studies have found relationships between negative affect and 1) amygdala over-activity and 2) reduced amygdala-prefrontal connectivity. However, it is not known whether elevated amygdala activity is associated with decreased amygdala-prefrontal connectivity during negative affect states.MethodsHere we used resting-state arterial spin labeling (ASL) and blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) in combination to test this model, measuring the activity (regional cerebral blood flow, rCBF) and functional connectivity (correlated fluctuations in the BOLD signal) of one subregion of the amygdala with strong connections with the prefrontal cortex, the basolateral nucleus (BLA), and subsyndromal anxiety levels in 38 healthy subjects.ResultsBLA rCBF was strongly correlated with anxiety levels. Moreover, both BLA rCBF and anxiety were inversely correlated with the strength of the functional coupling of the BLA with the caudal ventromedial prefrontal cortex. Lastly, BLA perfusion was found to be a mediator of the relationship between BLA-prefrontal connectivity and anxiety.ConclusionsThese results show that both perfusion of the BLA and a measure of its functional coupling with the prefrontal cortex directly index anxiety levels in healthy subjects, and that low BLA-prefrontal connectivity may lead to increased BLA activity and resulting anxiety. Thus, these data provide key evidence for an often-cited circuitry model of negative affect, using a novel, multi-modal imaging approach.

Heterogeneity of amygdala response in major depressive disorder: the impact of lifetime subthreshold mania

Patients with major depressive disorder (MDD) present with highly heterogeneous symptom profiles. We aimed to examine whether individual differences in amygdala activity to emotionally salient stimuli were related to heterogeneity in lifetime levels of depressive and subthreshold manic symptoms among adults with MDD. We compared age- and gender-matched adults with MDD (n = 26) with healthy controls (HC, n = 28). While undergoing functional magnetic resonance imaging, participants performed an implicit emotional faces task: they labeled a color flash superimposed upon initially neutral faces that dynamically morphed into one of four emotions (angry, fearful, sad, happy). Region of interest analyses examined group differences in amygdala activity. For conditions in which adults with MDD displayed abnormal amygdala activity versus HC, within-group analyses examined amygdala activity as a function of scores on a continuous measure of lifetime depression-related and mania-related pathology. Adults with MDD showed significantly greater right-sided amygdala activity to angry and happy conditions than HC (p < 0.05, corrected). Multiple regression analyses revealed that greater right-amygdala activity to the happy condition in adults with MDD was associated with higher levels of subthreshold manic symptoms experienced across the lifespan (p = 0.002). Among depressed adults with MDD, lifetime features of subthreshold mania were associated with abnormally elevated amygdala activity to emerging happy faces. These findings are a first step toward identifying biomarkers that reflect individual differences in neural mechanisms in MDD, and challenge conventional mood disorder diagnostic boundaries by suggesting that some adults with MDD are characterized by pathophysiological processes that overlap with bipolar disorder.

Elevated amygdala activity to negative faces in young adults with early onset major depressive disorder

Abnormalities in amygdala activity have been implicated in adolescents and older adults with major depressive disorder (MDD), but few studies have focused on young adults with early-onset MDD. In this study, we measured amygdala activity in 27 young adults with early-onset MDD and 25 healthy controls (HC) using functional magnetic resonance imaging (fMRI) with an emotional processing task. Both groups showed significant bilateral activation within the amygdala to threat-related facial expressions. In the matching face task, the activations of the left amygdala, thalamus, prefrontal and temporal cortex were significantly greater while the activation of the right prefrontal was significantly lower for the MDD group compared with the HC group. For the MDD group, there was a significant positive correlation between the activity of the amygdala and scores on the Chinese version of the Center for Epidemiologic Studies Depression Scale. Overall, our findings suggest that young adults with early-onset MDD may be characterized by abnormalities in nodes along the fronto-limbic pathways when facing threat-related facial expression.

There's that scary picture: Attention bias to threatening scenes in Williams syndrome

There is increasing evidence that Williams syndrome (WS) is associated with elevated anxiety that is non-social in nature, including generalised anxiety and fears. To date very little research has examined the cognitive processes associated with this anxiety. In the present research, attentional bias for non-social threatening images in WS was examined using a dot-probe paradigm. Participants were 16 individuals with WS aged between 13 and 34 years and two groups of typically developing controls matched to the WS group on chronological age and attentional control ability, respectively. The WS group exhibited a significant attention bias towards threatening images. In contrast, no bias was found for group matched on attentional control and a slight bias away from threat was found in the chronological age matched group. The results are contrasted with recent findings suggesting that individuals with WS do not show an attention bias for threatening faces and discussed in relation to neuroimaging research showing elevated amygdala activation in response to threatening non-social scenes in WS.

Elevated Amygdala Activity to Sad Facial Expressions: A State Marker of Bipolar but Not Unipolar Depression

Difficulties in emotion processing and poor social function are common to bipolar disorder (BD) and major depressive disorder (MDD) depression, resulting in many BD depressed individuals being misdiagnosed with MDD. The amygdala is a key region implicated in processing emotionally salient stimuli, including emotional facial expressions. It is unclear, however, whether abnormal amygdala activity during positive and negative emotion processing represents a persistent marker of BD regardless of illness phase or a state marker of depression common or specific to BD and MDD depression. Sixty adults were recruited: 15 depressed with BD type 1 (BDd), 15 depressed with recurrent MDD, 15 with BD in remission (BDr), diagnosed with DSM-IV and Structured Clinical Interview for DSM-IV Research Version criteria; and 15 healthy control subjects (HC). Groups were age- and gender ratio-matched; patient groups were matched for age of illness onset and illness duration; depressed groups were matched for depression severity. The BDd were taking more psychotropic medication than other patient groups. All individuals participated in three separate 3T neuroimaging event-related experiments, where they viewed mild and intense emotional and neutral faces of fear, happiness, or sadness from a standardized series. The BDd-relative to HC, BDr, and MDD-showed elevated left amygdala activity to mild and neutral facial expressions in the sad (p < .009) but not other emotion experiments that was not associated with medication. There were no other significant between-group differences in amygdala activity. Abnormally elevated left amygdala activity to mild sad and neutral faces might be a depression-specific marker in BD but not MDD, suggesting different pathophysiologic processes for BD versus MDD depression.

Divergent effects of amygdala glucocorticoid and mineralocorticoid receptors in the regulation of visceral and somatic pain

Elevated amygdala activity and increased responsiveness of the hypothalamic-pituitary-adrenal axis have been observed in irritable bowel syndrome (IBS) patients. Recently, we demonstrated that corticosterone (Cort) placed on the amygdala induced anxiety-like behavior coupled with decreased thresholds for visceral and somatic pain in rats. Moreover, these studies suggested that the effects of Cort were dependent on both the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR); however, the specific contributions of these receptors to the interaction between corticosteroids and the amygdala are still unclear. In the present study, we sought to define the distinct roles of amygdaloid GR and MR in anxiety-like behavior, visceral sensitivity, and somatic sensitivity through selective pharmacological activation. Male Fischer 344 rats received bilateral implants on the dorsal margin of the central amygdala containing the GR agonist dexamethasone (Dex), the MR agonist aldosterone (Aldo), or cholesterol as a control. Our results showed that GR or MR activation significantly reduced open arm exploration on the elevated plus maze, a measure of anxiety-like behavior. Aldo increased the number of abdominal muscle contractions in response to all levels of colorectal distension (CRD). In contrast, Dex only increased visceral sensitivity at noxious levels of CRD. Furthermore, GR but not MR activation reduced somatic pain thresholds measured by the mechanical force required to elicit hindlimb withdrawal. In summary, GR and MR mediated-mechanisms induce anxiety and visceral hypersensitivity, whereas somatic sensitivity involves only GR, suggesting that corticosteroids may enhance visceral and somatic sensation via divergent processes originating in the amygdala and involving specific steroid receptor mechanisms.

Amygdala activation during recognition of emotions in a foreign ethnic group is associated with duration of stay

Cultural differences in emotion recognition performance have frequently been reported, whereby duration of stay in a foreign culture seems to be a crucial factor. Furthermore, cultural aspects influence the neural correlates of face and emotion processing thereby also affecting the response of the amygdala. Here, the exposure to a foreign culture and its influence on the cerebral correlates of facial emotion recognition were examined in 24 Asian and 24 age-matched European males. Subjects performed an explicit emotion recognition task and were imaged with a 3 T MR-scanner. Results demonstrate a significant cultural influence on the specific recognition of disgust and anger, with higher accuracy among the Europeans, while the functional data indicate generally elevated amygdala activation in Asians compared to Europeans. Moreover, a significant inverse correlation between duration of stay and amygdala response emerged, with stronger activation in those subjects with shorter duration of stay in Europe. The observed amygdala hyperactivation in Asians may reflect novelty aspects but might also be associated with greater effort and motivation in immigrants, thus it possibly reflects one neural correlate of the “alien-effect”. We conclude that exposure to a foreign culture and duration of stay affect the behavioral and neural response to facial expressions of emotions.