Prefrontal Cortex Glutamate Correlates with Mental Perspective-Taking

Background

Dysfunctions in theory of mind and empathic abilities have been suggested as core symptoms in major psychiatric disorders including schizophrenia and autism. Since self monitoring, perspective taking and empathy have been linked to prefrontal (PFC) and anterior cingulate cortex (ACC) function, neurotransmitter variations in these areas may account for normal and pathological variations of these functions. Converging evidence indicates an essential role of glutamatergic neurotransmission in psychiatric diseases with pronounced deficits in empathy. However, the role of the glutamate system for different dimensions of empathy has not been investigated so far.

Methodology/Principal Findings

Absolute concentrations of cerebral glutamate in the ACC, left dorsolateral PFC and left hippocampus were determined by 3-tesla proton magnetic resonance spectroscopy (1H-MRS) in 17 healthy individuals. Three dimensions of empathy were estimated by a self-rating questionnaire, the Interpersonal Reactivity Index (IRI). Linear regression analysis showed that dorsolateral PFC glutamate concentration was predicted by IRI factor “perspective taking” (T = −2.710, p = 0.018; adjusted alpha-level of 0.017, Bonferroni) but not by “empathic concern” or “personal distress”. No significant relationship between IRI subscores and the glutamate levels in the ACC or left hippocampus was detected.

Conclusions/Significance

This is the first study to investigate the role of the glutamate system for dimensions of theory of mind and empathy. Results are in line with recent concepts that executive top-down control of behavior is mediated by prefrontal glutamatergic projections. This is a preliminary finding that needs a replication in an independent sample.     

Empathy and Belief in the Mental Experience of Animals

ABSTRACT

Aspects of empathy are examined, including the relationship between empathy and perceived similarity or identification. Cognitive judgments of similarity appear to predispose us to the experience of empathy. An important aspect of similarity where animals are concerned is their perceived mental endowment (Fenton & Hills 1988). Therefore, a positive relationship was hypothesized between empathy for animals and “belief in animal mind” (i.e., beliefs about the extent to which animals have awareness, thoughts, and feelings). In a sample comprising three groups (animal rights supporters, farmers, and urban public) the expected relationship was found, r(153) = .47, p < .001; however, it was not consistent across the subject groups. Analysis suggested that the relationship between perceived similarity and empathy is mediated by conflicting instrumental motivations. Implications of the results for humane and environmental education are discussed.     

Omega-3 and omega-6 fatty acid concentrations in red blood cell membranes relate to schizotypal traits in healthy adults

Reduced omega-3 and omega-6 fatty acids in red blood cell (RBC) membranes are often found in patients with schizophrenia. Here we investigated whether membrane concentrations of these fatty acids might vary as a function of schizotypal traits in non-psychotic individuals. Twenty-five healthy adults completed the O-LIFE schizotypal trait inventory and fatty acid composition of their venous blood samples was analysed via gas-liquid chromatography. Correlations between schizotypy measures and RBC fatty acids were examined and comparisons made between groups high and low on fatty acid measures and schizotypy scores. The omega-6 fatty acids arachidonic, adrenic and docosapentaenoic acid were directly related to positive schizotypal trait measures, as were most omega-3 fatty acids, but none were related to a negative, withdrawn form of schizotypy. Our findings of high RBC concentrations of omega-3 and omega-6 fatty acids in healthy adults with positive schizotypal traits clearly contrast with the low levels often found in schizophrenia, but are quite consistent with evidence that omega-3 fatty acids (notably EPA) can be useful in the treatment of schizophrenic illness.     

Schizotypy and behavioural adjustment and the role of neuroticism

Objective

In the present study the relationship between behavioural adjustment following cognitive conflict and schizotypy was investigated using a Stroop colour naming paradigm. Previous research has found deficits with behavioural adjustment in schizophrenia patients. Based on these findings, we hypothesized that individual differences in schizotypy, a personality trait reflecting the subclinical expression of the schizophrenia phenotype, would be associated with behavioural adjustment. Additionally, we investigated whether such a relationship would be explained by individual differences in neuroticism, a non-specific measure of negative trait emotionality known to be correlated with schizotypy.

Methods

106 healthy volunteers (mean age: 25.1, 60% females) took part. Post-conflict adjustment was measured in a computer-based version of the Stroop paradigm. Schizotypy was assessed using the Schizotypal Personality Questionnaire (SPQ) and Neuroticism using the NEO-FFI.

Results

We found a negative correlation between schizotypy and post-conflict adjustment (r = −.30, p<.01); this relationship remained significant when controlling for effects of neuroticism. Regression analysis revealed that particularly the subscale No Close Friends drove the effect.

Conclusion

Previous findings of deficits in cognitive control in schizophrenia patients were extended to the subclinical personality expression of the schizophrenia phenotype and found to be specific to schizotypal traits over and above the effects of negative emotionality.     

Effect of empathy trait on attention to various facial expressions: evidence from N170 and late positive potential (LPP)

Background

The present study sought to clarify the relationship between empathy trait and attention responses to happy, angry, surprised, afraid, and sad facial expressions. As indices of attention, we recorded event-related potentials (ERP) and focused on N170 and late positive potential (LPP) components.

Methods

Twenty-two participants (12 males, 10 females) discriminated facial expressions (happy, angry, surprised, afraid, and sad) from emotionally neutral faces under an oddball paradigm. The empathy trait of participants was measured using the Interpersonal Reactivity Index (IRI, J Pers Soc Psychol 44:113–126, 1983).

Results

Participants with higher IRI scores showed: 1) more negative amplitude of N170 (140 to 200 ms) in the right posterior temporal area elicited by happy, angry, surprised, and afraid faces; 2) more positive amplitude of early LPP (300 to 600 ms) in the parietal area elicited in response to angry and afraid faces; and 3) more positive amplitude of late LPP (600 to 800 ms) in the frontal area elicited in response to happy, angry, surprised, afraid, and sad faces, compared to participants with lower IRI scores.

Conclusions

These results suggest that individuals with high empathy pay attention to various facial expressions more than those with low empathy, from very-early stage (reflected in N170) to late-stage (reflected in LPP) processing of faces.     

Attitude to Animals and Empathy: Comparing Animal Protection and General Community Samples

ABSTRACT

Although a number of studies have examined a range of demographic and personality variables that may impact upon attitudes towards the treatment of non-human species, little consensus has been reached within the literature. The aim of the current study was to evaluate and assess levels of human-directed empathy and attitudes towards the treatment of animals in two diverse populations, namely the general community (n = 543) and those within the animal protection field (n = 389). Both groups of participants completed the Attitude Towards the Treatment of Animals Scale (AAS) and the Davis Interpersonal Reactivity Index (IRI), a measure of human-directed empathy. Comparisons between the two samples indicated that those within the animal protection community scored more highly on both the animal attitude and human-directed empathy measures. Correlational analyses revealed a positive relation between AAS and IRI scores for both samples, whilst the strength of the correlation was greater for those within the animal protection sample. These findings are discussed.     

A maternal influence on Reading the mind in the Eyes mediated by executive function: differential parental influences on full and half-siblings

Background

Parent-of-origin effects have been found to influence the mammalian brain and cognition and have been specifically implicated in the development of human social cognition and theory of mind. The experimental design in this study was developed to detect parent-of-origin effects on theory of mind, as measured by the ‘Reading the mind in the eyes’ (Eyes) task. Eyes scores were also entered into a principal components analysis with measures of empathy, social skills and executive function, in order to determine what aspect of theory of mind Eyes is measuring.

Methodology/Principal Findings

Maternal and paternal influences on Eyes scores were compared using correlations between pairs of full (70 pairs), maternal (25 pairs) and paternal siblings (15 pairs). Structural equation modelling supported a maternal influence on Eyes scores over the normal range but not low-scoring outliers, and also a sex-specific influence on males acting to decrease male Eyes scores. It was not possible to differentiate between genetic and environmental influences in this particular sample because maternal siblings tended to be raised together while paternal siblings were raised apart. The principal components analysis found Eyes was associated with measures of executive function, principally behavioural inhibition and attention, rather than empathy or social skills.

Conclusions/Significance

In conclusion, the results suggest a maternal influence on Eye scores in the normal range and a sex-specific influence acting to reduce scores in males. This influence may act via aspects of executive function such as behavioural inhibition and attention. There may be different influences acting to produce the lowest Eyes scores which implies that the heratibility and/or maternal influence on poor theory of mind skills may be qualitatively different to the influence on the normal range.     

BDNF Val66Met Polymorphism Is Associated with Self-Reported Empathy

Empathy is an important driver of human social behaviors and presents genetic roots that have been studied in neuroimaging using the intermediate phenotype approach. Notably, the Val66Met polymorphism of the Brain-derived neurotrophic factor (BDNF) gene has been identified as a potential target in neuroimaging studies based on its influence on emotion perception and social cognition, but its impact on self-reported empathy has never been documented. Using a neurogenetic approach, we investigated the association between the BDNF Val66Met polymorphism and self-reported empathy (Davis’ Interpersonal Reactivity Index; IRI) in a sample of 110 young adults. Our results indicate that the BDNF genotype is significantly associated with the linear combination of the four facets of the IRI, one of the most widely used self-reported empathy questionnaire. Crucially, the effect of BDNF Val66Met goes beyond the variance explained by two polymorphisms of the oxytocin transporter gene previously associated with empathy and its neural underpinnings (OXTR rs53576 and rs2254298). These results represent the first evidence suggesting a link between the BDNF gene and self-reported empathy and warrant further studies of this polymorphism due to its potential clinical significance.     

Emotional face recognition, empathic trait (BEES), and cortical contribution in response to positive and negative cues. The effect of rTMS on dorsal medial prefrontal cortex

The present study investigated the relationship between three different measures related to the affective empathy: facial expression detection in response to different emotional patterns (positive vs. negative), personal response to empathic scale [Balanced Emotional Empathy Scale (BEES)], and dorsal medial prefrontal cortex (dMPFC) contribution to mediate the facial detection task. Nineteen subjects took part in the study and they were required to recognize facial expression of emotions, after having empathized with these emotional cues. Repeated Transcranial Magnetic Stimulation (rTMS) method was used in the present research in order to produce a temporary virtual disruption of dMPFC activity. dMPFC disruption induced a worse performance, especially in response to negative expressions (i.e. anger and fear). High-BEES subjects paid a higher cost after frontal brain perturbation: they showed to be unable to correctly detect facial expressions more than low-BEES. Moreover, a “negative valence effect” was observed only for high-BEES, and it was probably related with their higher impairment to recognize negative more than positive expressions. dMPFC was found to support emotional facial expression recognition in an empathic condition, with a specific increased responsiveness for negative-valenced faces. The contribution of this research was discussed to explain the mechanisms underlying affective empathy based on rTMS application.     

Climatic effects on life-history traits of moose in Estonia

Weather variables can influence life-history traits of ungulates. In this study, we assessed the suitability of regional climate indices including the NAO and two measures of local climate—the maximal extent of ice on the Baltic Sea (MIE) and absolute values of its annual deviations from the multi-year mean (VMIE)—to examine how density-independent processes influence moose body size and fecundity. We predicted that both winter severity (large values of MIE) and variability (large values of VMIE) depress moose traits (e.g., severe winters increase energy expenditure because of large snow depth or low temperatures, while the warmer than average winters may impose greater energetic demands on thermoregulation due to wet and windy weather, or may have indirect negative effects on summer foraging conditions). We estimated direct, delayed (lag) and cumulative effects of each climate measure. Both MIE and VMIE negatively affected jawbone length, with the effect size varying between the respective climatic indices and among age classes. In contrast to results obtained using local climatic variables, the NAO index had no significant effect on jawbone length. The probability of multiple ovulation was negatively influenced by direct effects of VMIE and delayed effects of MIE and NAO. We conclude that MIE and VMIE capture different aspects of the local climate and that these indices can be used in parallel as determinants of growth and fecundity of northern ungulates in coastal regions of the Baltic Sea.     

Not As Good as You Think? Trait Positive Emotion Is Associated with Increased Self-Reported Empathy but Decreased Empathic Performance

How is positive emotion associated with our ability to empathize with others? Extant research provides support for two competing predictions about this question. An empathy amplification hypothesis suggests positive emotion would be associated with greater empathy, as it often enhances other prosocial processes. A contrasting empathy attenuation hypothesis suggests positive emotion would be associated with lower empathy, because positive emotion promotes self-focused or antisocial behaviors. The present investigation tested these competing perspectives by examining associations between dispositional positive emotion and both subjective (i.e., self-report) and objective (i.e., task performance) measures of empathy. Findings revealed that although trait positive emotion was associated with increased subjective beliefs about empathic tendencies, it was associated with both increases and decreases in task-based empathic performance depending on the target’s emotional state. More specifically, trait positive emotion was linked to lower overall empathic accuracy toward a high-intensity negative target, but also a higher sensitivity to emotion upshifts (i.e., shifts in emotion from negative to positive) toward positive targets. This suggests that trait positive affect may be associated with decreased objective empathy in the context of mood incongruent (i.e., negative) emotional stimuli, but may increase some aspects of empathic performance in the context of mood congruent (i.e., positive) stimuli. Taken together, these findings suggest that trait positive emotion engenders a compelling subjective-objective gap regarding its association with empathy, in being related to a heightened perception of empathic tendencies, despite being linked to mixed abilities in regards to empathic performance. (Word count: 242).     

Empathy and attitudes to animals

Abstract

There is increasing support for the idea that human attitudes to animals may be indicative of human–human empathy. This has implications for the treatment of empathy deficits and related anti-social behaviors. The purpose of the present study was to explicitly investigate links between human–human empathy and attitudes to animals. The Interpersonal Reactivity Index (IRI) and Animal Attitude Scale (AAS) were administered to 194 undergraduate Sociology and Psychology students. A significant correlation between empathy levels, gender, companion animal ownership and attitudes to animals was found. Implications of these findings are discussed.     

Association between Oxytocin Receptor Gene Polymorphisms and Self-Rated ‘Empathic Concern’ in Schizophrenia

The nonapeptide oxytocin (OXT) and its receptor (OXTR) have been implicated in social cognition, empathy, emotion and stress regulation in humans. Previous studies reported associations between OXT and OXTR genetic polymorphisms and risk for disorders characterized by impaired socio-emotional functioning, such as schizophrenia and autism. Here we investigate the influence of two single nucleotide polymorphisms (SNPs) within the OXTR gene on a measure of socio-emotional functioning in schizophrenic patients. OXTR SNPs that were previously investigated in other studies were genotyped in 145 patients diagnosed with schizophrenia according to DSM-IV and 145 healthy controls matched for age and gender. The Interpersonal Reactivity Index (IRI) was used to assess cognitive (‘perspective taking’), affective (‘empathic concern’) and self-related (‘personal distress’) dimensions of empathy. No group differences in genotype frequencies were observed. MANCOVA revealed a significant main (F [1,282] = 10.464; p<0.01) and interaction effect (genotype by diagnosis: F [1,282] = 4.329; p<0.05) of OXTR SNP rs2254298(A>GG) with ‘empathic concern’. Within the schizophrenia group, linear regression analysis determined OXTR rs2254298 genotype, PANSS negative and general symptom score, and age of disease onset as being significantly associated with ‘empathic concern’. OXTR rs2254298 significantly impacted PANSS general psychopathology scores. No associations were found for OXTR rs53576, IRI ‘perspective taking’ or ‘personal distress’ ratings. Our preliminary findings support hypotheses about an involvement of OXTR rs2254298 in emotional empathy in schizophrenic and healthy individuals, warranting independent replication.     

New Books

ABSTRACT

Past research found that positive attitudes toward animals are positively correlated with human-directed empathy. One of the most common reasons for becoming a vegetarian is to avoid cruelty toward animals. Based on the above literature, we hypothesized that vegetarians, especially moral vegetarians, would show higher human-directed empathy and more positive attitudes toward pets and other animals than non-vegetarians. Seventy-two vegetarians and 67 non-vegetarians participated in the study. Pet attitudes were measured using the modified Pet Attitude Scale (PAS-M), and human-directed empathy was measured with the Interpersonal Reactivity Index (IRI), which has four subscales. Vegetarian males had significantly higher empathy and significantly more positive attitudes toward pets compared with non-vegetarian males; however, there was no differences among females. There were no differences between moral vegetarians and non-moral vegetarians on human-directed empathy and attitude toward pets. Empathy toward humans and attitudes toward pets were positively correlated for both vegetarians and non-vegetarians. We conceptualized the dietary choice of a vegetarian as a lifestyle that can be explained by their political thinking, personality, and personal value systems.     

Empathy-Related Ratings to Still Images of Human and Nonhuman Animal Groups in Negative Contexts Graded for Phylogenetic Similarity

ABSTRACT

Research using film stimuli has shown that the strength of empathy-related responses toward nonhuman animals is related to the amount of phylogenetic similarity of the animals to humans. The present study aimed to develop and validate a new set of still images depicting humans and nonhuman animals (primates, quadruped mammals, birds, reptiles) in negative circumstances to provide greater control over variable image quality and contextual features found to be present in film stimuli. Following development of the stimulus set, participants (40 males, 46 females) with a mean age of 23.35 years made subjective ratings of empathy and other reactions to the images. The hypothesized effect of higher ratings of empathy for nonhuman animals that were more closely related to humans was supported. The same effect of phylogenetic similarity was also observed for ratings of arousal, dominance, interest, and pleasantness elicited by the images. Moreover, a clear effect of trait empathy emerged, consistent with the prediction that higher empathy ratings would be elicited from those higher in trait empathy. Familiarity, as assessed by level of involvement with the presence and care of animals, was also positively related to trait empathy. The findings validate a new methodology for the assessment of human empathy toward other humans and nonhuman species depicted in negative life situations. Furthermore, the findings demonstrate that human empathy generalizes toward other species according to perceived phylogenetic similarity.     

自闭症个体道德推理的心理机制及其脑机制

社交障碍是自闭症个体主要的临床症状之一,对他们的道德推理状况进行研究有助于我们解释这一现象.研究表明,自闭症个体在进行道德推理时和常人之间有所不同,而道德推理任务中经常包含有心理理解和移情方面的信息,提示我们自闭症个体的心理推理和移情能力可能是影响他们道德推理的内在心理机制.自闭症个体能够区分道德违背和习俗违背,但是他们经常判断不是故意造成的伤害是有意的.他们对伤害者的情绪线索也不太敏感,不能理解他人的感受,这种移情能力和道德推理能力之间的表现是相关的.此外,自闭症个体对道德推理的解释和言语发展水平之间也存在关联,他们经常通过重复故事情节、引述具体后果来解释道德推理,而缺乏对抽象道德规则的描述.脑成像研究表明,自闭症个体进行道德推理时在眶额叶皮质、杏仁核、脑岛、额下回、前扣带回、内侧前额叶皮质、默认网络模式、右颞顶联合区等部位的激活程度与常人存在着显著差异,这些部位同时也是心理理论或移情能力的重要脑区.自闭症个体在句子加工任务中言语功能联合区的激活程度也与常人存在差异,这可能是他们在对道德推理进行解释时存在困难的内部原因.未来研究需要考察心理理论、移情和言语能力对自闭症道德推理的交互作用,并采取非言语的方式对自闭症个体的道德推理进行研究,同时可通过脑损伤技术和激素水平的分析对影响他们道德推理的生理机制进行更加全面的考察.     

Cognitive abilities, androgen levels, and body mass index in 5-year-old children

This study explores the potential relationship between a series of cognitive abilities and testosterone, dehydroepiandrosterone (DHEA), androstenedione, and body mass index (BMI) measurements in 5-year-old children. 60 boys and 69 girls were administered a test (K-BIT) which provided measurements of fluid intelligence (Matrices subtest), crystallized intelligence (Vocabulary subtest), and IQ composite (the combination of the two subtests); a sub-sample of 48 boys and 61 girls was also subjected to diverse tests related to theory of mind (affective labeling, appearance-reality distinction, display rules, and false belief). Testosterone, DHEA, and androstenedione levels were measured using an enzyme immunoassay technique in saliva samples. An analysis of variance failed to reveal any significant differences between boys and girls in any of the cognitive abilities assessed. The correlation analysis revealed a positive relationship between fluid intelligence and testosterone levels in boys, a negative relationship between crystallized intelligence and androstenedione levels in girls, and between affective labeling and androstenedione levels in boys. A multiple regression analysis indicated that androstenedione and BMI were the best predictors for some of the cognitive abilities assessed.     

共情脑机制的研究现状与展望

作为社会交往中的重要因素,共情是指理解并体验他人的情感和知觉感受的能力。目前的研究认为共情依赖于直接的投射机制而非逻辑推理。即观察到他人的情绪状态会涉及一部分处理自我情感的大脑结构的激活,该过程同时还会受到社会认知因素的调节。由于理解和间接体验他人痛觉的能力是维系社会纽带必不可少的,目前研究者越来越多地通过对痛觉共情的研究来揭示关于共情的普遍的神经机制。此外共情的动物模型、镜像神经元系统与共情的产生以及共情的调节等方向也将是研究的重点。     

Emotion Regulation Moderates the Association between Empathy and Prosocial Behavior

Theory and evidence suggest that empathy is an important motivating factor for prosocial behaviour and that emotion regulation, i.e. the capacity to exert control over an emotional response, may moderate the degree to which empathy is associated with prosocial behaviour. However, studies to date have not simultaneously explored the associations between different empathic processes and prosocial behaviour, nor whether different types of emotion regulation strategies (e.g. cognitive reappraisal and expressive suppression) moderate associations between empathy and prosocial behaviour. One hundred–and-ten healthy adults completed questionnaire measures of empathy, emotion regulation and prosocial tendencies. In this sample, both affective and cognitive empathy predicted self-reported prosocial tendencies. In addition, cognitive reappraisal moderated the association between affective empathy and prosocial tendencies. Specifically, there was a significant positive association between empathy and prosocial tendencies for individuals with a low or average tendency to reappraise but not for those with a high tendency to reappraise. Our findings suggest that, in general, empathy is positively associated with prosocial behaviour. However, this association is not significant for individuals with a high tendency for cognitive reappraisal.