Temperament has been described as an oligogenic model that confers attributes to individuals in their daily functioning. Understanding of these temperaments can help understanding psychiatric status and therapeutic needs of a patient population. As the Latino population grows providers need to become more familiar with their psychiatric status.
To describe how the characteristics of different temperament domains in a community vs a private practice clinic of patients being treated for a mood disorder.
Retrospective record review was conducted in 117 patients with mood disorders who received the Temperament Scale (TEMPS). Forty nine were from a community clinic (CM) and 68 from a private practice (PP).
The following temperament domains were found. In PP: depressed 17/69 (25%); cyclothymic 18/69 (26%); hyperthymic 16/69 (23%); anxious 14/68 (20%); irritable 4/69 (5%). Among CM: depressed 10/49 (20%); cyclothymic 14/49 (28%); hyperthymic 8/49 (16%); anxious 15/49 (30%); irritable 2/49 (5%). Using factor analysis to determine the significant domains among clinics, cyclothima (0.82) and irritability (0.81) were the most relevant, regardless of psychosocial background and language differences.
Cross-sectional retrospective study without longitudinal follow up.
This study elucidates how temperament domains could be considered a valuable tool in evaluating patients in mood disorders clinic. The tool elucidates valuable characteristics that could be applied for guidance in diagnosis and treatment without being biased by different socio-cultural background or language differences. The factor analysis helps elucidate the pertinence of TEMPS scores that may not be the focus of clinical intervention although they contribute significantly to the structure of an individual's temperament, specifically emotional labiality (i.e., cyclothima and irritability).
Temperament; Rural; Cyclothymia
A low level of response (LR) to alcohol is an important endophenotype associated with an increased risk for alcoholism. However, little is known about how neural functioning may differ between individuals with low and high LRs to alcohol. This study examined whether LR group effects on neural activity varied as a function of acute alcohol consumption.
30 matched high- and low-LR pairs (N=60 healthy young adults) were recruited from the University of California, San Diego and administered a structured diagnostic interview and laboratory alcohol challenge followed by two fMRI sessions under placebo and alcohol conditions, in randomized order. Task performance and BOLD response contrast to high relative to low working memory load in an event-related visual working memory (VWM) task was examined across 120 fMRI sessions.
Both LR groups performed similarly on the VWM task across conditions. A significant LR group by condition interaction effect was observed in inferior frontal and cingulate regions, such that alcohol attenuated the LR group differences found under placebo (p<.05). The LR group by condition effect remained even after controlling for cerebral blood flow, age, and typical drinking quantity.
Alcohol had differential effects on brain activation for low and high LR individuals within frontal and cingulate regions. These findings represent an additional step in the search for physiological correlates of a low LR, and identify brain regions that may be associated with the low LR response.
Level of response; fMRI; visual working memory; cerebral blood flow
Touch is a fundamental, but complex, element of everyday interaction that impacts one’s sensory and affective experience via interoceptive processing. The insular cortex is an integral component of the neural processes involved in interoception, i.e. the generation of an “emotional moment in time” through the sensing of the internal body state (Craig, 2002). Here, we examine the contribution of different parts of the insular cortex in the representation of both affective and sensory aspects of touch. To that end, subjects were administered a cued application of touch during functional MRI. We find that stimulus-related activation occurs in the mid-to-posterior insula, whereas anticipatory related activation is seen mostly in anterior insula. Moreover, the degree of activation in anterior insula during anticipation is correlated with the degree of activation in the posterior insula and caudate during stimulus processing. Finally, the degree of activation in the anterior insula during anticipation is also correlated with experienced intensity of the touch. Taken together, these results are consistent with the hypothesis that the anterior insula is preparing for the sensory and affective impact of touch. This preparatory function has important implications for the understanding of both anxiety and addictive disorders because dysfunctions in anticipatory processing are a fundamental part of the psychopathology.
Ineffective emotion regulation and abnormal amygdala activation have each been found in adolescent-onset major depressive disorder. However, amygdala activation during emotion regulation has not been studied in adolescent-onset major depressive disorder.
Fourteen unmedicated adolescents diagnosed with current depression without comorbid psychiatric disorders and fourteen well-matched controls ages 13 to 17 years underwent an emotional regulation task during functional magnetic resonance imaging. During this task, participants viewed negatively-valence images and were asked to notice how they were feeling without trying to change it and maintain their emotional reaction (“Maintain”) or to interpret the image in such a way as minimize their emotional response (“Reduce”).
Imaging analyses demonstrated that adolescents with depression showed: (1) greater right amygdala activation during the maintain condition relative to controls, (2) less connectivity during the maintain condition between the amygdala and both the insula and medial prefrontal cortex than controls, and (3) a significant positive correlation between amygdala-seeded connectivity during maintenance of emotion and psychosocial functioning.
The current study is cross-sectional comparison and longitudinal investigations with larger sample sizes are needed to examine the association between amygdala reactivity and emotion regulation over time in adolescent MDD.
During the maintain condition, adolescents with depression showed a heightened amygdala response and less reciprocal activation in brain regions that may modulate the amygdala. A poorly modulated, overreactive amygdala may contribute to poor emotion regulation.
Major Depression; Functional MRI; Insula; Reappraisal; Prefrontal Cortex
Liberals and conservatives exhibit different cognitive styles and converging lines of evidence suggest that biology influences differences in their political attitudes and beliefs. In particular, a recent study of young adults suggests that liberals and conservatives have significantly different brain structure, with liberals showing increased gray matter volume in the anterior cingulate cortex, and conservatives showing increased gray matter volume in the in the amygdala. Here, we explore differences in brain function in liberals and conservatives by matching publicly-available voter records to 82 subjects who performed a risk-taking task during functional imaging. Although the risk-taking behavior of Democrats (liberals) and Republicans (conservatives) did not differ, their brain activity did. Democrats showed significantly greater activity in the left insula, while Republicans showed significantly greater activity in the right amygdala. In fact, a two parameter model of partisanship based on amygdala and insula activations yields a better fitting model of partisanship than a well-established model based on parental socialization of party identification long thought to be one of the core findings of political science. These results suggest that liberals and conservatives engage different cognitive processes when they think about risk, and they support recent evidence that conservatives show greater sensitivity to threatening stimuli.
Sensation seeking has been linked to increased risk taking and is therefore crucial in influencing behavioral outcomes of risk-taking behavior. Using functional magnetic resonance imaging (fMRI), the neural underpinnings of risk appraisal were studied in a large subject sample (n=188), stratified according to thrill and adventure seeking (TAS) ratings. As defined by a median split of the sample, low and high TAS groups were compared on a simple decision-making task completed during fMRI. The task was designed such that risk (i.e., magnitude of outcome) and gains (i.e., direction of outcome) could be mapped independently. Behavioral analysis indicated that high TAS individuals are more sensitive to rewards but less discriminating between risk with and without punishment and that low TAS individuals are less sensitive to rewards but quite sensitive to receiving punishments in risky situations. Imaging results on the group differences for the interaction between level of risk and level of gain showed differences in the right superior frontal gyrus (BA6), left insula (BA21), right nucleus accumbens, left lentiform nucleus, and left precuneus (BA7). The presented data suggest a neural model of risk processing in sensation seeking individuals such that the positive response to reward outweighs the impact of equivalent loss. This imbalance in approach/avoidance is evident in differences in the underlying neural substrates in TAS individuals and leads to greater risk behavior in the face of potential loss.
sensation seeking; fMRI; SFG; neural correlates; decision making; risk taking
Aims: Alcohol acutely reduces agitation and is widely used in social situations, but the neural substrates of emotion processing during its intoxication are not well understood. We examine whether alcohol's social stress dampening effect may be via reduced activity in the cortical systems that subserve awareness of bodily sensations, and are associated with affective distress. Methods: Blood oxygen level-dependent activation was measured through 24 functional magnetic resonance imaging sessions in 12 healthy volunteers during an emotional face-processing task following ingestion of a moderate dose of alcohol and a placebo beverage. Results: Results revealed that bilateral anterior insula response to emotional faces was significantly attenuated following consumption of alcohol, when compared with placebo (clusters >1472 μl; corrected P < 0.05). Conclusion: Attenuated response in the anterior insula after alcohol intake may explain some of the decreased interoceptive awareness described during intoxication.
Several studies provide empirical evidence for the association between impulsivity and time perception. However, little is known about the neural substrates underlying this function. This investigation examined the influence of impulsivity on neural activation patterns during the encoding and reproduction of intervals with durations of 3, 9 and 18 seconds using event-related functional magnetic resonance imaging (fMRI). Twenty-seven subjects participated in this study, including 15 high impulsive subjects that were classified based on their self-rating. FMRI activation during the duration reproduction task was correlated with measures of two self-report questionnaires related to the concept of impulsivity (Barratt Impulsiveness Scale, BIS; Zimbardo Time Perspective Inventory, ZTPI). Behaviorally, those individuals who under-reproduced temporal intervals also showed lower scores on the ZTPI future perspective subscale and higher scores on the BIS. FMRI activation revealed an accumulating pattern of neural activity peaking at the end of the 9- and 18-s interval within right posterior insula. Activations of brain regions during the reproduction phase of the timing task, such as those related to motor execution as well as to the ‘core control network’ – encompassing the inferior frontal and medial frontal cortex, the anterior insula as well as the inferior parietal cortex – were significantly correlated with reproduced duration, as well as with BIS and ZTPI subscales. In particular, the greater activation in these regions the shorter were the reproduced intervals, the more impulsive was an individual and the less pronounced the future perspective. Activation in the core control network, thus, may form a biological marker for cognitive time management and for impulsiveness.
time perception; duration reproduction; impulsivity; time perspective; fMRI
Pregabalin (PGB) has shown potential as an anxiolytic for treatment of generalized and social anxiety disorder. PGB binds to voltage-dependent calcium channels, leading to upregulation of GABA inhibitory activity and reduction in the release of various neurotransmitters. Previous functional magnetic resonance imaging (fMRI) studies indicate that selective serotonin reuptake inhibitors and benzodiazepines attenuate amygdala, insula, and medial prefrontal cortex activation during anticipation and emotional processing in healthy controls. The aim of this study was to examine whether acute PGB administration would attenuate activation in these regions during emotional anticipation. In this double-blind, placebo-controlled, randomized crossover study, 16 healthy controls completed a paradigm involving anticipation of negative and positive affective images during fMRI approximately 1 h after administration of placebo, 50, or 200 mg PGB. Linear mixed model analysis revealed that PGB was associated with (1) decreases in left amygdala and anterior insula activation and (2) increases in anterior cingulate (ACC) activation, during anticipation of positive and negative stimuli. There was also a region of the anterior amygdala in which PGB dose was associated with increased activation during anticipation of negative and decreased activation during anticipation of positive stimuli. Attenuation of amygdala and insula activation during anticipatory or emotional processing may represent a common regional brain mechanism for anxiolytics across drug classes. PGB induced increases in ACC activation could be a unique effect related to top–down modulation of affective processing. These results provide further support for the viability of using pharmaco-fMRI to determine the anxiolytic potential of pharmacologic agents.
pregabalin; neuroimaging; insula; amygdala; anticipation; psychopharmacology; neuropharmacology; psychopharmacology; mood/anxiety/stress disorders; imaging; clinical or preclinical; pregabalin; anxiety; insula; prefrontal cortex; amygdala
As an individual moves from adolescence to adulthood, they need to form a new sense of self as their environment changes from a limited to a more expansive structure. During this critical stage in development the last dramatic steps of neural development occur and numerous psychiatric conditions begin to manifest. Currently, there is no measure that aids in the quantification of how the individual is adapting to, and conceptualizing their role in, these new structures. To fill this gap we created the Self and World Evaluation Expressions Test(SWEET).
Sixty-five young adults (20.6 years-old), 36 with a history of drug use, completed the SWEET. A factor analysis was performed on the SWEET and the resultant factors were correlated with psychological, neuropsychological, and neuroanatomical battery that included both T1-wieghted and diffusion tensor magnetic resonance imaging scans.
We derived four factors: Self, Social-Emotional, Financial-Intellectual, and Spirituality. While showing limited relationships to psychological and neuropsychological measures, both white matter integrity and gray matter density showed significant relationships with SWEET factors.
These findings suggest that while individual responses may not be indicative of psychological or cognitive processes they may relate to changes in brain structure. Several of these structures, such as the negative correlation of the affective impact of world with the dorsal anterior corpus callosum white matter integrity have been observed in psychiatric conditions (e.g., obsessive-compulsive disorder). Further longitudinal research using the SWEET may help understand the impact of dramatic shifts in self/world conceptualization and potentially link these shifts to underlying changes in brain structure.
It is unclear whether and how elite athletes process physiological or psychological challenges differently than healthy comparison subjects. In general, individuals optimize exercise level as it relates to differences between expected and experienced exertion, which can be conceptualized as a body prediction error. The process of computing a body prediction error involves the insular cortex, which is important for interoception, i.e. the sense of the physiological condition of the body. Thus, optimal performance may be related to efficient minimization of the body prediction error. We examined the hypothesis that elite athletes, compared to control subjects, show attenuated insular cortex activation during an aversive interoceptive challenge.
Elite adventure racers (n = 10) and healthy volunteers (n = 11) performed a continuous performance task with varying degrees of a non-hypercapnic breathing load while undergoing functional magnetic resonance imaging. The results indicate that (1) non-hypercapnic inspiratory breathing load is an aversive experience associated with a profound activation of a distributed set of brain areas including bilateral insula, dorsolateral prefrontal cortex and anterior cingulated; (2) adventure racers relative to comparison subjects show greater accuracy on the continuous performance task during the aversive interoceptive condition; and (3) adventure racers show an attenuated right insula cortex response during and following the aversive interoceptive condition of non-hypercapnic inspiratory breathing load.
These findings support the hypothesis that elite athletes during an aversive interoceptive condition show better performance and an attenuated insular cortex activation during the aversive experience. Interestingly, differential modulation of the right insular cortex has been found previously in elite military personnel and appears to be emerging as an important brain system for optimal performance in extreme environments.
Previous neuroimaging studies suggest that prefrontal cortex (PFC) modulation of the amygdala and related limbic structures is an underlying neural substrate of effortful emotion regulation. Anxiety-prone individuals experience excessive negative emotions, signaling potential dysfunction of systems supporting down-regulation of negative emotions. We examined the hypothesis that anxious individuals require increased recruitment of lateral and medial PFC to decrease negative emotions. An emotion regulation task that involved viewing moderately negative images was presented during functional magnetic resonance imaging (fMRI). Participants with elevated trait anxiety scores (n = 13) and normal trait anxiety scores (n = 13) were trained to reduce negative emotions using cognitive reappraisal. Blood oxygenation level-dependent (BOLD) changes were contrasted for periods when participants were reducing emotions versus when they were maintaining emotions. Compared to healthy controls, anxious participants showed greater activation of brain regions implicated in effortful (lateral PFC) and automatic (subgenual anterior cingulate cortex) control of emotions during down-regulation of negative emotions. Left ventrolateral PFC activity was associated with greater self-reported reduction of distress in anxious participants, but not in healthy controls. These findings provide evidence of altered functioning of neural substrates of emotion regulation in anxiety-prone individuals. Anxious participants required greater engagement of lateral and medial PFC in order to successfully reduce negative emotions.
Emotion; Emotion Regulation; fMRI; Anxiety; Prefrontal Cortex; Anterior Cingulate Cortex
Exposure to combat can have a significant impact across a wide array of domains, and may manifest as post-traumatic stress disorder (PTSD), a debilitating mental illness that is associated with neural and affective sequelae. This study tested the hypothesis that combat-exposed individuals with and without PTSD, relative to healthy control subjects with no history of PTSD or combat exposure, would show amygdala hyperactivity during performance of a well-validated face processing task. We further hypothesized that differences in the prefrontal cortex would best differentiate the combat-exposed groups with and without PTSD.
Twelve men with PTSD related to combat in Operations Enduring Freedom and/or Iraqi Freedom, 12 male combat-exposed control patients with a history of Operations Enduring Freedom and/or Iraqi Freedom combat exposure but no history of PTSD, and 12 healthy control male patients with no history of combat exposure or PTSD completed a face-matching task during functional magnetic resonance imaging.
The PTSD group showed greater amygdala activation to fearful versus happy faces than both the combat-exposed control and healthy control groups. Both the PTSD and the combat-exposed control groups showed greater amygdala activation to all faces versus shapes relative to the healthy control group. However, the combat-exposed control group relative to the PTSD group showed greater prefrontal/parietal connectivity with the amygdala, while the PTSD group showed greater connectivity with the subgenual cingulate. The strength of connectivity in the PTSD group was inversely related to avoidance scores.
These observations are consistent with the hypothesis that PTSD is associated with a deficiency in top-down modulation of amygdala activation by the prefrontal cortex and shows specific sensitivity to fearful faces.
Imaging studies of posttraumatic stress disorder (PTSD) have identified functional differences in the amygdala and anterior cingulate (ACC)/medial prefrontal cortex during emotion processing. Recent investigations of the limbic sensory system and its associated neural substrate, the insular cortex, have demonstrated its importance for emotional awareness. Intimate-partner violence (IPV) is one of the most common causes of PTSD among women. This study examined the hypothesis that women with IPV-PTSD show a dysregulation of this limbic sensory system while processing threat-related emotional faces.
12 women with IPV-PTSD and 12 non-traumatized comparison women underwent BOLD functional magnetic resonance imaging while completing an emotional-face matching task.
IPV-PTSD subjects relative to comparison subjects displayed increased activation of the anterior insula and amygdala and decreased connectivity among the anterior insula, amygdalae, and ACC while matching to fearful vs. happy target faces. A similar pattern of activation differences was also observed for angry vs. happy target faces. IPV-PTSD subjects relative to comparison subjects also displayed increased dACC/mPFC activation and decreased vACC activation when matching to a male vs. a female target, and the extent of increased dACC activation correlated positively with hyperarousal symptoms.
Women with IPV-PTSD display hyperactivity and disconnection among affective and limbic sensory systems while processing threat-related emotion. Furthermore, hyperactivity of cognitive-appraisal networks in IPV-PTSD may promote hypervigilant states of awareness through an exaggerated sensitivity to contextual cues, i.e. male gender, which relate to past trauma.
posttraumatic stress; anxiety; emotion; insula; amygdala; anterior cingulate
A number of studies have examined the perception of time with durations ranging from milliseconds to a few seconds, however the neural basis of these processes are still poorly understood and the neural substrates underlying the perception of multiple-second intervals are unknown. Here we present evidence of neural systems activity in circumscribed areas of the human brain involved in the encoding of intervals with durations of 9 and 18 seconds in a temporal reproduction task using event-related functional magnetic resonance imaging (fMRI). During the encoding there was greater activation in more posterior parts of the medial frontal and insular cortex whereas the reproduction phase involved more anterior parts of these brain structures. Intriguingly, activation curves over time show an accumulating pattern of neural activity, which peaks at the end of the interval within bilateral posterior insula and superior temporal cortex when individuals are presented with 9- and 18-second tone intervals. This is consistent with an accumulator-type activity, which encodes duration in the multiple seconds range. Given the close connection between the dorsal posterior insula and ascending internal body signals, we suggest that the accumulation of physiological changes in body states constitutes our experience of time. This is the first time that an accumulation function in the posterior insula is detected that might be correlated with the encoding of time intervals.
time perception; duration reproduction; insular cortex; fMRI
Medial cortex is critically involved in self-referential processing. Little is known about how SSRIs affect medial cortical activity during self-assessment. We hypothesized that 3 week oral administration of escitalopram 10mg per day would alter activity related to self-referential processing in medial cortex. Fifteen healthy females performed a self-assessment task during fMRI on two occasions – once after 3 weeks of placebo and once at the end of 3 weeks of escitalopram. Task conditions involved responding “yes” or “no” to whether various positive and negative adjectives described the subject (i.e., “self” evaluation trials) or the subject’s best friend (i.e., “other” evaluation trials), whereas the comparison condition involved responding whether the valence of various adjectives was positive or negative (i.e., “word” evaluation trials). Behaviorally after escitalopram, subjects less frequently endorsed that negative adjectives described themselves. Three main neuroimaging results were observed: (1) increased activation in medial prefrontal cortex and posterior cingulate related to self minus word evaluation trials, (2) increased activation in posterior cingulate related to escitalopram minus placebo for self and word evaluation trials, (3) drug by task interactions in the insula, cerebellum and prefrontal cortex. These results show that SSRIs change medial cortical activity and may alter self-evaluation.
SSRI; medial cortex; fMRI; self; cingulate; emotion processing
An intact ability to mount preparatory emotional, cognitive and bodily responses to anticipated environmental change is necessary for adaptive responding. Although abnormal insula activity during aversive anticipation has been observed in Major Depressive Disorder (MDD) individuals, the extent to which shifts in homeostatic state during anticipation affect insular activity in MDD subjects has not been reported. The aim of this study was to use functional Magnetic Resonance Imaging (fMRI) to examine how shifts in homeostatic state affect anticipatory insular activity in MDD.
Cued hot and warm stimuli were delivered while subjects either passively viewed a fixation cross or performed an attentional task during fMRI. The task was designed so that anticipatory brain activation related to the following three types of shifts could be measured: (1) anticipatory shifts in stimulus intensity, (2) anticipatory shifts in cognitive demand, (3) dual anticipatory shifts (i.e., shifts in both stimulus intensity and cognitive demand). Brain activation related to each of these three contrasts was compared between 15 (12F) unmedicated subjects with current MDD and 17 (10F) age- and education-comparable healthy control (HC) subjects.
MDD versus HC subjects showed lower right anterior insula activity related to anticipatory shifts in stimulus intensity, and altered brain activation during anticipatory shifts in cognitive demand and dual anticipatory shifts.
These results indicate that MDD individuals show altered brain responses to shifts in homeostatic state during anticipation, and may suggest that MDD is associated with an impaired ability to effectively prepare for changes in the environment.
Homeostatsis; emotion; interoception; fmri; emotional allodynia; heat; pain
The allocation of attention modulates negative emotional processing in the amygdala. However, the role of passive exposure time to emotional signals in the modulation of amygdala activity during active task performance has not been examined. In two functional Magnetic Resonance Imaging (fMRI) experiments conducted in two different groups of healthy human subjects, we examined activation in the amygdala due to cued anticipation of painful stimuli while subjects performed a simple continuous performance task (CPT) with either a fixed or a parametrically varied trial duration. In the first experiment (N = 16), engagement in the CPT during a task with fixed trial duration produced the expected attenuation of amygdala activation, but close analysis suggested that the attenuation occurred during the period of active engagement in CPT, and that amygdala activity increased proportionately during the remainder of each trial, when subjects were passively exposed to the pain cue. In the second experiment (N = 12), the duration of each trial was parametrically varied, and we found that amygdala activation was linearly related to the time of passive exposure to the anticipatory cue. We suggest that amygdala activation during negative anticipatory processing depends directly on the passive exposure time to the negative cue.
Functional neuroimaging studies have led to a significantly deeper understanding of the underlying neural correlates and the development of several mature models of depression in adults. In contrast, our current understanding of the underlying neural substrates of adolescent depression is very limited. Although numerous studies have consistently demonstrated a hyperactive amygdala in depressed adults, the few published pediatric studies have reported opposite results in the amygdala. Thus, the main purpose of this study was to further our knowledge of the underlying neural substrates of adolescent depression by examining the bilateral amygdala specifically and the whole brain in depressed adolescents compared to healthy controls.
Twelve unmedicated adolescents diagnosed with current major depressive disorder without a comorbid psychiatric disorder and 12 well-matched controls ages 13 to 17 years performed a facial-emotion matching task during functional magnetic resonance imaging at 3 T.
Region-of-interest analyses demonstrated: (1) significant bilateral amygdala activation in depressed and healthy adolescents, and (2) significantly greater left amygdala activation in depressed adolescents compared to controls. Whole-brain analysis revealed areas of significantly different brain activity in depressed adolescents compared to controls.
These results suggest that (1) depressed adolescents without a comorbid psychiatric disorder exhibit an abnormally hyperactive amygdala compared to healthy controls; (2) models of adult depression might be extended to include depressed adolescents; and (3) neuropsychiatric interventions that have been developed in depressed adults should be further examined in adolescents. J. Am. Acad. Child Adolesc.
functional magnetic resonance imaging; amygdala; neuroimaging; anterior cingulate cortex; major depressive disorder
Little is known about the neural basis of elite performers and their optimal performance in extreme environments. The purpose of this study was to examine brain processing differences between elite warfighters and comparison subjects in brain structures that are important for emotion processing and interoception.
Navy Sea, Air, and Land Forces (SEALs) while off duty (n = 11) were compared with n = 23 healthy male volunteers while performing a simple emotion face-processing task during functional magnetic resonance imaging. Irrespective of the target emotion, elite warfighters relative to comparison subjects showed relatively greater right-sided insula, but attenuated left-sided insula, activation. Navy SEALs showed selectively greater activation to angry target faces relative to fearful or happy target faces bilaterally in the insula. This was not accounted for by contrasting positive versus negative emotions. Finally, these individuals also showed slower response latencies to fearful and happy target faces than did comparison subjects.
These findings support the hypothesis that elite warfighters deploy greater processing resources toward potential threat-related facial expressions and reduced processing resources to non-threat-related facial expressions. Moreover, rather than expending more effort in general, elite warfighters show more focused neural and performance tuning. In other words, greater neural processing resources are directed toward threat stimuli and processing resources are conserved when facing a nonthreat stimulus situation.
Recent adult studies suggest that the subgenual anterior cingulate cortex (sgACC) is involved in fundamental mental operations such as affective processing and inhibitory control. However, little is known about inhibition-associated sgACC function in adolescents, and there are no published data regarding whether personality characteristics are related to inhibition-associated sgACC brain activity in adolescents. This study examined the relationship between personality and inhibition-associated sgACC response in healthy adolescents. Seventeen adolescents of 13–17 years of age underwent functional magnetic resonance imaging while performing a parametric stop-signal task. Greater harm avoidance levels were significantly associated with increased inhibition-related sgACC activity. These results establish, for the first time, a link between personality and differential sgACC activation in adolescents.
adolescents; emotion; functional MRI; harm avoidance; personality; subgenual anterior cingulate; temperament and character inventory
Resilience, i.e., the ability to cope with stress and adversity, relies heavily on judging adaptively complex situations. Judging facial emotions is a complex process of daily living that is important for evaluating the affective context of uncertain situations, which could be related to the individual's level of resilience. We used a novel experimental paradigm to test the hypothesis that highly resilient individuals show a judgment bias towards positive emotions.
65 non-treatment seeking subjects completed a forced emotional choice task when presented with neutral faces and faces morphed to display a range of emotional intensities across sadness, fear, and happiness.
Overall, neutral faces were judged more often to be sad or fearful than happy. Furthermore, high compared to low resilient individuals showed a bias towards happiness, particularly when judging neutral faces.
This is a cross-sectional study with a non-clinical sample.
These results support the hypothesis that resilient individuals show a bias towards positive emotions when faced with uncertain emotional expressions. This capacity may contribute to their ability to better cope with certain types of difficult situations, perhaps especially those that are interpersonal in nature.
Emotion perception; Resilience; Facial expressions; Neutral faces
The anterior cingulate cortex (ACC) and insula are important neural substrates for the integration of cognitive, emotional, and physiological information, as well as the coordination of responses to anticipated stimuli. Increased neural activation within these structures has been observed in individuals with anxiety and depressive disorders. Selective serotonin reuptake inhibitors (SSRIs) are among the most effective and frequently prescribed anxiolytic agents, yet it is not known whether ACC or insula underlie the effects of these drugs. We examined whether subchronic administration of an SSRI to healthy volunteers attenuate activation in ACC or insula during anticipation, an important emotional process underlying anxiety. Support for this hypothesis would help to understand where and by what process SSRIs may exert beneficial effects as anxiolytics and would provide further mechanistic evidence for functional magnetic resonance imaging (fMRI) as a biomarker for the development of anxiolytics.
Participants and Design
15 volunteers participated in a double-blind, placebo-controlled, randomized cross-over study. Participants completed a pleasant and aversive picture cued anticipation task during fMRI after taking either escitalopram (10 mg) or placebo for 21 days.
Main Outcome Measure
Percent BOLD signal change during SSRI administration.
Escitalopram significantly decreased activation in bilateral posterior and middle insula during the anticipation condition irrespective of stimulus valence and in medial prefrontal and ACC during anticipation of aversive versus pleasant images.
Reduced insular and ACC activation during anticipation may be integral to the therapeutic efficacy of SSRIs and provide a mechanistic approach for the use of pharmacofMRI in the identification of novel pharmacotherapeutic agents.
SSRI; escitalopram; insula; fMRI; anticipation
The amygdala and insular cortex are integral to the processing of emotionally salient stimuli. We have shown in healthy volunteers that an anxiolytic agent, lorazepam, dose-dependently attenuates activation of limbic structures.
The current study investigated whether administration of a selective serotonin reuptake inhibitor (SSRI), escitalopram, alters the activation of limbic structures. We hypothesized that subchronic (21 days) SSRI treatment attenuates the activation of the amygdala and insula during processing of emotional faces.
Thirteen healthy volunteers participated in a double-blind, placebo-controlled, cross-over, randomized study. After 21 days of treatment with either escitalopram or placebo, participants underwent functional magnetic resonance imaging (fMRI) during which all subjects completed an emotion face assessment task, which has been shown to elicit amygdala and insula activation.
Subjects activated the bilateral insula and amygdala following treatment with both escitalopram and placebo. In subjects who were adherent to the protocol (as evidenced by sufficiently high urine concentrations of escitalopram), a reduction in amygdala activation was seen in the escitalopram condition compared to placebo.
The current investigation provides further evidence for the mechanism of action of SSRIs through the attenuation of activation in brain regions responsible for emotion processing and provides support for the use of BOLD-fMRI with pharmacological probes to help identify the specific therapeutic effect of these agents in patients with anxiety and mood disorders.
SSRI; escitalopram; insula; amygdala; fMRI; emotion processing
Neuroimaging studies implicate the subgenual anterior cingulate cortex (sgACC) as a critical brain region in adult depression. However, unlike adult depression, little is known about the underlying neural substrates of adolescent depression, and there are no published data examining differences in sgACC activation between depressed and healthy adolescents. This study used functional magnetic resonance imaging to examine sgACC activity in twenty-six depressed and normal 13- to 17-year olds during the performance of a stop-signal task. Significantly greater sgACC activation was found in the depressed adolescents relative to controls. These results establish for the first time abnormal functioning of the sgACC in depressed adolescents and have important implications for understanding the underlying neural correlates and potential treatments of adolescent depression.
adolescent; depression; FMRI; subgenual anterior cingulate cortex; prefrontal cortex; major depressive disorder; functional neuroimaging; functional MRI; pediatrics; mood disorder