What is the basic structure of emotional experience and how is it represented in the human brain? One highly influential theory, discrete basic emotions, proposes a limited set of basic emotions such ...as happiness and fear, which are characterized by unique physiological and neural profiles. Although many studies using diverse methods have linked particular brain structures with specific basic emotions, evidence from individual neuroimaging studies and from neuroimaging meta-analyses has been inconclusive regarding whether basic emotions are associated with both consistent and discriminable regional brain activations. We revisited this question, using activation likelihood estimation (ALE), which allows spatially sensitive, voxelwise statistical comparison of results from multiple studies. In addition, we examined substantially more studies than previous meta-analyses. The ALE meta-analysis yielded results consistent with basic emotion theory. Each of the emotions examined (fear, anger, disgust, sadness, and happiness) was characterized by consistent neural correlates across studies, as defined by reliable correlations with regional brain activations. In addition, the activation patterns associated with each emotion were discrete (discriminable from the other emotions in pairwise contrasts) and overlapped substantially with structure–function correspondences identified using other approaches, providing converging evidence that discrete basic emotions have consistent and discriminable neural correlates. Complementing prior studies that have demonstrated neural correlates for the affective dimensions of arousal and valence, the current meta-analysis results indicate that the key elements of basic emotion views are reflected in neural correlates identified by neuroimaging studies.
► Meta-analysis examined sex differences in emotion-related activation. ► Marked sex differences in several emotion processing areas were found. ► Women had greater amygdala activation for negative ...emotion. ► Men had greater amygdala activation for positive emotion. ► Findings accord with reported behavioral sex differences.
Substantial sex differences in emotional responses and perception have been reported in previous psychological and psychophysiological studies. For example, women have been found to respond more strongly to negative emotional stimuli, a sex difference that has been linked to an increased risk of depression and anxiety disorders. The extent to which such sex differences are reflected in corresponding differences in regional brain activation remains a largely unresolved issue, however, in part because relatively few neuroimaging studies have addressed this issue. Here, by conducting a quantitative meta-analysis of neuroimaging studies, we were able to substantially increase statistical power to detect sex differences relative to prior studies, by combining emotion studies which explicitly examined sex differences with the much larger number of studies that examined only women or men. We used an activation likelihood estimation approach to characterize sex differences in the likelihood of regional brain activation elicited by emotional stimuli relative to non-emotional stimuli. We examined sex differences separately for negative and positive emotions, in addition to examining all emotions combined. Sex differences varied markedly between negative and positive emotion studies. The majority of sex differences favoring women were observed for negative emotion, whereas the majority of the sex differences favoring men were observed for positive emotion. This valence-specificity was particularly evident for the amygdala. For negative emotion, women exhibited greater activation than men in the left amygdala, as well as in other regions including the left thalamus, hypothalamus, mammillary bodies, left caudate, and medial prefrontal cortex. In contrast, for positive emotion, men exhibited greater activation than women in the left amygdala, as well as greater activation in other regions including the bilateral inferior frontal gyrus and right fusiform gyrus. These meta-analysis findings indicate that the amygdala, a key region for emotion processing, exhibits valence-dependent sex differences in activation to emotional stimuli. The greater left amygdala response to negative emotion for women accords with previous reports that women respond more strongly to negative emotional stimuli, as well as with hypothesized links between increased neurobiological reactivity to negative emotion and increased prevalence of depression and anxiety disorders in women. The finding of greater left amygdala activation for positive emotional stimuli in men suggests that greater amygdala responses reported previously for men for specific types of positive stimuli may also extend to positive stimuli more generally. In summary, this study extends efforts to characterize sex differences in brain activation during emotion processing by providing the largest and most comprehensive quantitative meta-analysis to date, and for the first time examining sex differences as a function of positive vs. negative emotional valence. The current findings highlight the importance of considering sex as a potential factor modulating emotional processing and its underlying neural mechanisms, and more broadly, the need to consider individual differences in understanding the neurobiology of emotion.
The ability to cope adaptively with emotional events by volitionally altering one's emotional reactions is important for psychological and physical health as well as social interaction. Cognitive ...regulation of emotional responses to aversive events engages prefrontal regions that modulate activity in emotion-processing regions such as the amygdala. However, the neural correlates of the regulation of positive emotions remain largely unexplored. We used event-related functional magnetic resonance imaging to examine the neural correlates of cognitively increasing and decreasing emotional reactions to positive and negative stimuli. Participants viewed negative, positive, and neutral pictures while attempting to increase, decrease, or not alter their emotional reactions. Subjective reactions were assessed via on-line ratings. Consistent with previous studies, increasing negative and positive emotion engaged primarily left-lateralized prefrontal regions, whereas decreasing emotion activated bilateral prefrontal regions. Different activations unique to increasing versus decreasing emotion were observed for positive and negative stimuli: Unique increase-related activations were observed only for positive stimuli, whereas unique decrease-related activations were observed only for negative stimuli. Regulation also modulated activity in the amygdala, a key emotion-processing region. Regulation effects on amygdala activity were larger for positive than for negative stimuli, potentially reflecting a greater malleability of positive emotional reactions. Increasing and decreasing positive and negative emotion can thus increase and decrease subjective reactions and associated amygdala activity in line with regulatory goals, and is associated with different patterns of prefrontal activation as a function of emotional valence and regulatory goal.
Compassion is closely associated with prosocial behavior. Although there is growing interest in developing strategies that cultivate compassion, most available strategies rely on effortful reflective ...processes. Furthermore, few studies have investigated neurocognitive mechanisms underlying compassion-dependent improvement of prosocial responses. We devised a novel implicit compassion promotion task that operates based on association learning and examined its prosocial effects in two independent experiments. In Experiment 1, healthy adults were assigned to either the compassion or control group. For the intervention task, the compassion group completed word fragments that were consistently related to compassionate responses toward others; in contrast, the control group completed word fragments related to emotionally neutral responses toward others. Following the intervention task, we measured attentional biases to fearful, sad, and happy faces. Prosocial responses were assessed using two measures of helping: the pen-drop test and the helping intentions rating test. In Experiment 2, independent groups of healthy adults completed the same intervention tasks used in Experiment 1. Inside a functional MRI scanner, participants rated empathic care and distress based on either distressful or neutral video clips. Outside the scanner, we assessed the degree of helping intentions toward the victims depicted in the distressful clips. The results of Experiment 1 showed that the compassion promotion task reduced attentional vigilance to fearful faces, which in turn mediated a compassion promotion task-dependent increase in helping intentions. In Experiment 2, relative to the control group, the compassion group showed reduced empathic distress and increased activity in the medial orbitofrontal cortex in response to others’ suffering. Furthermore, increased functional connectivity of the medial orbitofrontal and inferior parietal cortex, predicted by reduced empathic distress, explained the increase in helping intentions. These results suggest the potential of implicit compassion promotion intervention to modulate compassion-related and prosocial responses as well as highlight the brain activation and connectivity related to these responses, contributing to our understanding of the neurocognitive mechanisms underlying compassion-dependent prosocial improvement.
A longstanding controversy in the field of emotion research has concerned whether emotions are better conceptualized in terms of discrete categories, such as fear and anger, or underlying dimensions, ...such as arousal and valence. In the domain of neuroimaging studies of emotion, the debate has centered on whether neuroimaging findings support characteristic and discriminable neural signatures for basic emotions or whether they favor competing dimensional and psychological construction accounts. This review highlights recent neuroimaging findings in this controversy, assesses what they have contributed to this debate, and offers some preliminary conclusions. Namely, although neuroimaging studies have identified consistent neural correlates associated with basic emotions and other emotion models, they have ruled out simple one-to-one mappings between emotions and brain regions, pointing to the need for more complex, network-based representations of emotion.
We investigated the effect of cognitive reappraisal on emotional arousal, facial expressivity and subsequent memory. Men and women viewed emotionally negative pictures while they attempted to either ...increase or decrease negative emotions elicited by the pictures, or to simply view the pictures. Neutral pictures were also presented with instructions to simply view the pictures. Concurrent changes in emotional arousal and valence were assessed with skin conductance responses (SCRs) and facial corrugator electromyographic responses (EMG), respectively. Picture memory was assessed with an immediate recall test and a delayed recognition test. Relative to simply viewing pictures, voluntary reappraisal to increase negative emotion generated greater facial corrugator EMG and SCR responses, and reappraisal to decrease negative emotion generated decreased corrugator EMG responses. Men showed enhanced recognition for pictures presented during the increase and decrease conditions, whereas women showed comparable recognition performance across all regulation conditions. The modulation of subsequent recognition memory associated with decreasing emotion was inversely associated with changes in physiological responses. Our results suggest that sex is an important factor to consider in determining how reappraisal-induced physiological changes are associated with subsequent changes in memory. These findings contribute to our understanding of how reappraising emotion exerts both immediate and enduring influences on physiological responses and subsequent memory.
► Effects of cognitive reappraisal on physiological and memory outcomes were examined. ► Increasing negative emotion led to greater facial corrugator EMG and SCR responses. ► Decreasing negative emotion led to decreased facial EMG activity. ► Men showed overall improved recognition for pictures presented while reappraising. ► Results feature affective and cognitive consequences of cognitive reappraisal.
The amygdala is a structure in the temporal lobe that has long been known to play a key role in emotional responses and emotional memory in both humans and nonhuman animals. Growing evidence from ...recent neuroimaging studies points to a new, expanded role for the amygdala as a critical structure that mediates sex differences in emotional memory and sexual responses. This review highlights current findings from studies of sex differences in human amygdala response during emotion-related activities, such as formation of emotional memories and sexual behavior, and considers how these findings contribute to the understanding of behavioral differences between men and women. Clinical implications for the understanding of sex differences in the prevalence of affective and anxiety disorders are discussed, and future directions in the study of the amygdala’s role in human sex differences are outlined.
The amygdala is a key structure mediating emotional processing. Few studies have used direct electrical stimulation of the amygdala in humans to examine stimulation-elicited physiological and ...emotional responses, and the nature of such effects remains unclear. Determining the effects of electrical stimulation of the amygdala has important theoretical implications for current discrete and dimensional neurobiological theories of emotion, which differ substantially in their predictions about the emotional effects of such stimulation. To examine the effects of amygdala stimulation on physiological and subjective emotional responses we examined epilepsy patients undergoing intracranial EEG monitoring in which depth electrodes were implanted unilaterally or bilaterally in the amygdala. Nine subjects underwent both sham and acute monopolar electrical stimulation at various parameters in electrode contacts located in amygdala and within lateral temporal cortex control locations. Stimulation was applied at either 50 Hz or 130 Hz, while amplitudes were increased stepwise from 1 to 12 V, with subjects blinded to stimulation condition. Electrodermal activity (EDA), heart rate (HR), and respiratory rate (RR) were simultaneously recorded and subjective emotional response was probed after each stimulation period. Amygdala stimulation (but not lateral control or sham stimulation) elicited immediate and substantial dose-dependent increases in EDA and decelerations of HR, generally without affecting RR. Stimulation elicited subjective emotional responses only rarely, and did not elicit clinical seizures in any subject. These physiological results parallel stimulation findings with animals and are consistent with orienting/defensive responses observed with aversive visual stimuli in humans. In summary, these findings suggest that acute amygdala stimulation in humans can be safe and can reliably elicit changes in emotion physiology without significantly affecting subjective emotional experience, providing a useful approach for investigation of amygdala-mediated modulatory effects on cognition.
•Increasing amplitudes of amygdala stimulation elicited dose-dependent increases in EDA and decreases in heart rate.•In one patient, amygdala stimulation caused subjective experiences of fear and anxiety, accompanied by increased heart rate.•Amygdala stimulation reliably elicits changes in autonomic activity in a dose-dependent and safe manner.•At the amplitudes of stimulation delivered, amygdala stimulation elicits subjective emotional experiences only infrequently.
In this functional neuroimaging study, we investigated neural activations during the process of learning to gain monetary rewards and to avoid monetary loss, and how these activations are modulated ...by individual differences in reward and punishment sensitivity. Healthy young volunteers performed a reinforcement learning task where they chose one of two fractal stimuli associated with monetary gain (reward trials) or avoidance of monetary loss (avoidance trials). Trait sensitivity to reward and punishment was assessed using the behavioral inhibition/activation scales (BIS/BAS). Functional neuroimaging results showed activation of the striatum during the anticipation and reception periods of reward trials. During avoidance trials, activation of the dorsal striatum and prefrontal regions was found. As expected, individual differences in reward sensitivity were positively associated with activation in the left and right ventral striatum during reward reception. Individual differences in sensitivity to punishment were negatively associated with activation in the left dorsal striatum during avoidance anticipation and also with activation in the right lateral orbitofrontal cortex during receiving monetary loss. These results suggest that learning to attain reward and learning to avoid loss are dependent on separable sets of neural regions whose activity is modulated by trait sensitivity to reward or punishment.
Severe neuropsychiatric conditions, such as schizophrenia, affect distributed neural computations. One candidate system profoundly altered in chronic schizophrenia involves the thalamocortical ...networks. It is widely acknowledged that schizophrenia is a neurodevelopmental disorder that likely affects the brain before onset of clinical symptoms. However, no investigation has tested whether thalamocortical connectivity is altered in individuals at risk for psychosis or whether this pattern is more severe in individuals who later develop full-blown illness.
To determine whether baseline thalamocortical connectivity differs between individuals at clinical high risk for psychosis and healthy controls, whether this pattern is more severe in those who later convert to full-blown illness, and whether magnitude of thalamocortical dysconnectivity is associated with baseline prodromal symptom severity.
In this multicenter, 2-year follow-up, case-control study, we examined 397 participants aged 12-35 years of age (243 individuals at clinical high risk of psychosis, of whom 21 converted to full-blown illness, and 154 healthy controls). The baseline scan dates were January 15, 2010, to April 30, 2012.
Whole-brain thalamic functional connectivity maps were generated using individuals' anatomically defined thalamic seeds, measured using resting-state functional connectivity magnetic resonance imaging.
Using baseline magnetic resonance images, we identified thalamocortical dysconnectivity in the 243 individuals at clinical high risk for psychosis, which was particularly pronounced in the 21 participants who converted to full-blown illness. The pattern involved widespread hypoconnectivity between the thalamus and prefrontal and cerebellar areas, which was more prominent in those who converted to full-blown illness (t(173) = 3.77, P < .001, Hedge g = 0.88). Conversely, there was marked thalamic hyperconnectivity with sensory motor areas, again most pronounced in those who converted to full-blown illness (t(173) = 2.85, P < .001, Hedge g = 0.66). Both patterns were significantly correlated with concurrent prodromal symptom severity (r = 0.27, P < 3.6 × 10(-8), Spearman ρ = 0.27, P < 4.75 × 10(-5), 2-tailed).
Thalamic dysconnectivity, resembling that seen in schizophrenia, was evident in individuals at clinical high risk for psychosis and more prominently in those who later converted to psychosis. Dysconnectivity correlated with symptom severity, supporting the idea that thalamic connectivity may have prognostic implications for risk of conversion to full-blown illness.
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