Article

Effect of the catechol- O -methyltransferase Val 158 Met polymorphism on theory of mind in obesity

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Abstract

Obesity is often accompanied with psychosocial adjustment problems, such as difficulties in social interactions and social withdrawal. A key aspect of social cognition is theory of mind, which allows inferring mental states, feelings, motivations, and beliefs of others and to use this information to predict their future behaviour. Theory of mind is highly dependent on prefrontal dopaminergic neurotransmission, which is regulated by catechol‐O‐methyltransferase (COMT) activity. We aimed at determining whether theory of mind is altered in obesity and if this ability is modulated by COMT. Fifty patients with obesity and 47 normal‐weight individuals underwent the Reading the Mind in the Eyes Test, the Wisconsin Card Sorting Test, and the Vocabulary subscale of the Wechsler Adult Intelligence Scale. The genotype for the COMT Val ¹⁵⁸Met functional polymorphism was determined for all subjects. Patients with obesity obtained significantly lower scores in the negative items of the Reading the Mind in the Eyes Test than normal‐weight subjects. Further, an interaction effect was observed between group and COMT genotype. Specifically, the presence of the Met allele was associated to a better identification of negative mental states only in patients with obesity. Our results indicate that obesity is accompanied with difficulties in theory of mind and that this ability is influenced by the COMT genotype.

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... The differences in valence across the RMET items have been categorized into positive, negative, and neutral items (Hudson et al., 2020). Lower accuracy for positive RMET items has been reported in clinical samples such as Borderline Personality Disorder (Anupama et al., 2018;Meyer & Morey, 2015;Scott et al., 2011), obesity (Caldu et al., 2019), Parkinson Disease (Yu et al., 2018), and pre-frontal lesions (Shaw et al., 2005). In contrast, enhanced performance on RMET items with negative valence have been found in samples with childhood abuse (Weinstein et al., 2016) and Major Depressive Disorder (Nejati, 2018). ...
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... The expression of COMT mRNA and protein was decreased by the proinflammatory cytokine tumor necrosis factor alpha (TNFa) in astrocytes, and neuroinflammation could be found in the recovery phase (45). There were at least eight different SNPs loci obtained on COMT gene, among which Val158Met locus had been studied the most frequently (46). COMT polymorphisms are manifested as a valine (Val or G) and methionine (Met or A) mutation at codon 158. ...
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... Being less sensitive to such social cues may have direct consequences for the dynamics of social interactions. The present findings are also consistent with preliminary evidence that high BMI is associated with reduced emotion recognition, which some studies have already established in children and adolescents [51][52][53] but see also [54]. ...
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Article
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Chapter
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Although social functioning is clearly impaired in anorexia nervosa (AN), there has been limited empirical assessment of this domain in this illness. This study assesses social cognition in AN by examining performance on two 'theory of mind' (ToM) tasks; Baron-Cohen's "Reading the mind in the Eyes" task (RME) and Happé's cartoon task. These tasks probe affective and cognitive ToM, respectively. Forty-four female participants were recruited (AN N=22; healthy controls N=22) and completed both tasks, with concurrent clinical and intellectual functioning assessment. Compared with healthy controls, AN performed significantly worse on both the RME and the Cartoon task (both conditions). The mental state condition did not facilitate performance in the AN group, as it did in the healthy controls. The findings broadly replicate limited previous work [Tchanturia, K., Happé, F., Godley, J., Bara-Carill, N., Treasure, J., Schmidt, U., 2004. Theory of mind in AN. European Eating Disorders Review 12, 361-366] but in addition demonstrate abnormalities on a task requiring affective ToM interpretation. More detailed information about the components of ToM and the ToM difficulties demonstrated in AN sufferers may inform our understanding of the disorder as well as future social-cognitive based treatments.
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The functional catechol-O-methyltransferase (COMT Val108/158Met) polymorphism has been shown to have an impact on tasks of executive function, memory and attention and recently, tasks with an affective component. As oestrogen reduces COMT activity, we focused on the interaction between gender and COMT genotype on brain activations during an affective processing task. We used functional MRI (fMRI) to record brain activations from 74 healthy subjects who engaged in a facial affect recognition task; subjects viewed and identified fearful compared to neutral faces. There was no main effect of the COMT polymorphism, gender or genotypexgender interaction on task performance. We found a significant effect of gender on brain activations in the left amygdala and right temporal pole, where females demonstrated increased activations over males. Within these regions, Val/Val carriers showed greater signal magnitude compared to Met/Met carriers, particularly in females. The COMT Val108/158Met polymorphism impacts on gender-related patterns of activation in limbic and paralimbic regions but the functional significance of any oestrogen-related COMT inhibition appears modest.
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Referring to the alexithymia construct and Bruch's clinical observations, this study investigated the ability to decode nonverbal signs of emotion in obese boys and girls, and their mothers. A group of 10 boys and 11 girls with obesity and their mothers, and a control group were tested. Both mothers and children were asked to recognize a set of 32 brief film sequences interpreted by four actors expressing four emotions (anger, sadness, fear, happiness) with two intensity levels. Each sequence was presented first without sound, second without video, and finally with video and sound. As expected, boys and girls suffering from obesity and their mothers showed a reduced ability to decode visual and verbal signs of emotion compared to the control group. This result may be interpreted in accordance with the alexithymia construct, and suggests the importance of developing therapeutic strategies to face alexithymic characteristics in obese children and their mothers.
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We report the dynamic anatomical sequence of human cortical gray matter development between the age of 4-21 years using quantitative four-dimensional maps and time-lapse sequences. Thirteen healthy children for whom anatomic brain MRI scans were obtained every 2 years, for 8-10 years, were studied. By using models of the cortical surface and sulcal landmarks and a statistical model for gray matter density, human cortical development could be visualized across the age range in a spatiotemporally detailed time-lapse sequence. The resulting time-lapse "movies" reveal that (i) higher-order association cortices mature only after lower-order somatosensory and visual cortices, the functions of which they integrate, are developed, and (ii) phylogenetically older brain areas mature earlier than newer ones. Direct comparison with normal cortical development may help understanding of some neurodevelopmental disorders such as childhood-onset schizophrenia or autism.
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Using a sample of sibling pairs discordant for psychosis, the authors attempted to replicate the findings of previous studies suggesting that the functional genetic polymorphism Val158Met in the catechol O-methyltransferase (COMT) gene influences prefrontal cognitive function and increases the risk for schizophrenia. Eighty-nine sibling pairs discordant for psychosis were genotyped for this polymorphism and were assessed with the Wisconsin Card Sorting Test, a measure of prefrontal function. Additionally, the preferential transmission of alleles for this polymorphism was analyzed in a sample of 89 nuclear families in order to examine the genetic association. In the healthy siblings, a linear relationship was seen in which performance on the Wisconsin Card Sorting Test was associated in an allele dosage fashion with COMT genotype (i.e., fewer perseverative errors with higher number of methionine alleles). However, this association was not observed in patients. Furthermore, no evidence of genetic association with psychosis was detected. These results seem to confirm the role of COMT genotype in the modulation of executive functions related to frontal lobe function in healthy individuals but not in schizophrenia patients.
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Objectives: In this study we aimed to evaluate emotion recognition and emotion regulation skills of children with exogenous obesity between ages of 11 and 18 years and compare them with healthy controls. Methods: Schedule for Affective Disorders and Schizophrenia for School Aged Children, were used for psychiatric evaluations. Emotion recognition skills were evaluated using Faces Test and Reading the Mind in the Eyes Test. Difficulties in Emotions Regulation Scale was used for evaluating skills of emotion regulation. Results: Children with obesity had lower scores on Faces Test and Reading the Mind in the Eyes Test, and experienced greater difficulty in emotional regulation skills. Conclusions: Improved understanding of emotional recognition and emotion regulation in young people with obesity may improve their social adaptation and helps by treatment of their disorder. To the best of our knowledge, this is the first study to evaluate both emotional recognition and emotion regulation functions in obese children and obese adolescents between 11 and 18 years of age.
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Emotional problems often co-occur in overweight or obese children. However, questions of whether emotion recognition deficits are present and how they are reflected have only been sparsely investigated to date. Therefore, the present study included 33 overweight and obese as well as 33 normal weight elementary school children between six and ten years that were matched for sex, age and socioeconomic status. Participants were shown different emotional faces of a well-validated set of stimuli on a computer screen, which they categorized and then rated on an emotional intensity level. Key measures were categorization performance along with reaction times and emotional intelligence as well as emotional eating questionnaire ratings. Overweight children exhibited lower categorization accuracy as well as longer reaction times as compared to normal weight children, while no differences in intensity ratings occurred. Reaction time to neutral facial expressions was negatively related to intrapersonal and interpersonal emotional intelligence and emotional eating correlated negatively with accuracy for recognizing sad expressions. Facial emotion decoding difficulties seem to be of importance in overweight and obese children and deserve further consideration in terms of their exact impact on social functioning as well as on the maintenance of elevated body weight during child development. Copyright © 2015 Elsevier Inc. All rights reserved.
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Patients with limited focal frontal and nonfrontal lesions were tested for visual perspective taking and detecting deception. Frontal lobe lesions impaired the ability to infer mental states in others, with dissociation of performance within the frontal lobes. Lesions throughout the frontal lobe, with some suggestion of a more important role for the right frontal lobe, were associated with impaired visual perspective taking. Medial frontal lesions, particularly right ventral, impaired detection of deception. The former may require cognitive processes of the lateral and superior medial frontal regions, the latter affective connections of the ventral medial frontal with amygdala and other limbic regions.
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The prevalence of obesity is increasing worldwide. Previous research has shown a relationship between obesity and both executive functioning alterations and frontal cortex volume reductions. The Brain Derived Neurotrophic Factor val66met polymorphism, involved in eating behavior, has also been associated with executive functions and prefrontal cortex volume, but to date it has not been studied in relation to obesity. Our aim is to elucidate whether the interaction between the Brain Derived Neurotrophic Factor val66met polymorphism and obesity status influences executive performance and frontal-subcortical brain structure. Sixty-one volunteers, 34 obese and 27 controls, age range 12-40, participated in the study. Participants were assigned to one of two genotype groups (met allele carriers, n = 16, or non-carriers, n = 45). Neuropsychological assessment comprised the Trail Making Test, the Stroop Test and the Wisconsin Card Sorting Test, all tasks that require response inhibition and cognitive flexibility. Subjects underwent magnetic resonance imaging in a Siemens TIM TRIO 3T scanner and images were analyzed using the FreeSurfer software. Analyses of covariance controlling for age and intelligence showed an effect of the obesity-by-genotype interaction on perseverative responses on the Wisconsin Card Sorting Test as well as on precentral and caudal middle frontal cortical thickness: obese met allele carriers showed more perseverations on the Wisconsin Card Sorting Test and lower frontal thickness than obese non-carriers and controls. In conclusion, the Brain Derived Neurotrophic Factor may play an important role in executive functioning and frontal brain structure in obesity. © 2014 Wiley Periodicals, Inc.
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Few studies have investigated overweight trajectories and psychosocial adjustment among adolescents. We conducted analyses with data from the multisite Study of Early Child Care and Youth Development (SECCYD). Sample included 1,350 youth born in 1991. Data consisted of repeated measures of weight, height, and multiple subscales of internalizing and externalizing behavioral problems measured by the Child Behavior Checklist (CBCL) from age nine to age 15. Three trajectory patterns were identified: never/rarely overweight/obese (59.5%), late start/light overweight/obese (12.1%), and chronically/heavy overweight/obese (28.4%). Youths with chronically/heavy overweight/obese trajectory pattern had significantly higher scores of internalizing problems over time, as well as syndrome subscales of somatic complaints, social problems and social withdrawal over time than youths with the never/rare overweight/obese trajectory pattern. There was no significant difference in either broad-band behavioral problems or narrow-band syndrome subscales between youths with the never/rare overweight/obese trajectory pattern and those with the late start/light overweight/obesity trajectory pattern. Study findings may advance knowledge on the distinct developmental trajectory patterns of overweight youth and their linkages to the psychosocial adjustment during the period of pubertal transition. The results highlight the need for future prevention research to improve the physical development and mental well-being of adolescents.
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Dopamine beta-hydroxylase (DBH), an enzyme that converts dopamine to norepinephrine, has broad influences on social functions. In this study, we examined to what extent two polymorphisms (−1021C/T and a 19 bp insertion/deletion) in DBH gene modulate individuals’ empathic perception and response, which were measured, respectively, by reading the mind in the eyes test and the empathic concern subscale of interpersonal reactivity index. Results showed that polymorphism at −1021C/T, but not the 19 bp insertion/deletion, accounts for 2.3% variance of empathic perception and 1.4% variance of empathic response. Individuals with the CC genotype, which is associated with higher DBH activity, manifested greater empathic ability than those with CT/TT genotypes. These findings demonstrate the importance of DBH −1021C/T as a genetic basis of empathy and in predicting individual differences in social and affective processing.
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Whether genetic factors affect social cognition, particularly emotion management, requires elucidation. This study investigates whether social cognition varies with genetic variations of COMT and tryptophan hydroxylase-2 (TPH2), which modulate dopamine and serotonin neurotransmissions respectively, and thereby emotion regulation. NIMH-recommended "managing emotions branch and 2 subtasks" of MSCEIT and six neurocognition domains, and genotypes of COMT Val158Met and TPH2 G703T were measured in 150 Han-Chinese healthy adults. Subjects carrying the M allele (M group) of COMT exceeded Val/Val homozygotes (V group) in managing emotions branch (p = 0.032) and emotional relation subtask (p = 0.037). TPH2 T/T homozygotes (T group) excelled those with the G allele (G group) in emotional management subtask (p = 0.025). Subjects with M+T variation surpassed the other 3 groups (M+G, V+T and V+G) in managing emotion branch (p = 0.002), emotional relation subtask (p = 0.023), and emotional management subtask (p = 0.002). The findings remained after control for gender, age, education, and neurocognitive functions. Synergistically, the effect size of COMT-TPH2 combination surmounted the sum of separate effect sizes of COMT and TPH2. The findings suggest that genetic variations of COMT and TPH2 have synergistic effects on social cognition in the general population.
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This study aimed to assess cognitive and affective theory of mind (ToM) in patients with eating disorders and to explore its relationship with the clinical and psychopathological profile. Theory of mind was assessed in 65 women, consisting of 22 with anorexia nervosa (AN), 19 with bulimia nervosa (BN), and 24 healthy controls (HC), using the Reading the Mind in the Eyes Test and the Faux Pas Test. These tasks evaluate affective and cognitive ToM, respectively. We also examined the correlations between performance on ToM tasks and the clinical psychopathological profile, which was extensively evaluated through self-report instruments and clinical interviews. Patients with AN had poorer performance than BN patients and HCs had in the affective ToM task, particularly in recognizing negative emotions and emotions in male eyes. Moreover, this deficit showed no correlation with the psychopathological profile. Performance in the BN group was equivalent to that of HCs in both tasks. In this study, patients with AN showed an impairment in affective ToM, independent of their clinical status. Consistent with other studies, our findings demonstrate a specific difficulty in social cognition in patients with AN. This may be a trait marker in this population and should be considered in treatment. Furthermore, patients with AN and BN have different difficulty profiles in this domain of social cognition. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association.
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ABSTRACT– A self-assessment scale has been developed and found to be a reliable instrument for detecting states of depression and anxiety in the setting of an hospital medical outpatient clinic. The anxiety and depressive subscales are also valid measures of severity of the emotional disorder. It is suggested that the introduction of the scales into general hospital practice would facilitate the large task of detection and management of emotional disorder in patients under investigation and treatment in medical and surgical departments.
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Individual differences in preschoolers' understanding that human action is caused by internal mental states, or representational theory of mind (RTM), are heritable, as are developmental disorders such as autism in which RTM is particularly impaired. We investigated whether polymorphisms of genes affecting dopamine (DA) utilization and metabolism constitute part of the molecular basis of this heritability. Seventy-three 42- to 54-month-olds were given a battery of RTM tasks along with other task batteries that measured executive functioning and representational understanding more generally. Polymorphisms of the dopamine D4 receptor gene (DRD4) were associated with RTM performance such that preschoolers with shorter alleles outperformed those with one or more longer alleles. However, polymorphisms of the catechol-O-methyl transferase gene (COMT) and the dopamine transporter gene (DAT1) genes were not associated with children's RTM performance. Further tests showed that the association between DRD4 allele length and RTM performance was not attributable to a common association with executive functioning or representational understanding more generally. We conclude that DRD4 receptors, likely via their effects on frontal lobe development and functioning, may represent a neuromaturational constraint governing the stereotypical and universal trajectory of RTM development.
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Objective: Clinical accounts and previous evidence suggest that socio-emotional impairments may be present in people with bulimia nervosa (BN). The aim of this paper was to systematically review studies of social cognition, and to evaluate whether social cognitive deficits exist in BN. Method: Keywords were identified using an existing model of social cognition (Green et al., 2007) [16], and used to search for relevant papers in three online databases. Records were then screened according to a priori inclusion/exclusion criteria. Results: Five papers reporting seven social cognition tasks were identified as pertinent to the review. All involved either theory of mind ability or emotional processing skills. Participants with BN had impaired performance on the Levels of Emotional Awareness Scale and showed greater attentional bias than controls on an emotional Stroop task. There were no overall group differences for any other tasks, although there were small differences for some specific test items. Conclusions: Basic social cognition does not appear to be impaired in people with BN. Future research should make use of more complex, ecologically valid measures, and consider the relationship between task performance and everyday social functioning.
Article
This paper presents a novel neurobiological model of theory of mind (ToM) that incorporates both neuroanatomical and neurochemical levels of specificity. Within this model, cortical and subcortical regions are functionally organized into networks that subserve the ability to represent cognitive and affective mental states to both self and other. The model maintains that (1) cognitive and affective aspects of ToM are subserved by dissociable, yet interacting, prefrontal networks. The cognitive ToM network primarily engages the dorsomedial prefrontal cortex, the dorsal anterior cingulate cortex and the dorsal striatum; and the affective ToM network primarily engages the ventromedial and orbitofrontal cortices, the ventral anterior cingulate cortex, the amygdala and the ventral striatum; (2) self and other mental-state representation is processed by distinct brain regions within the mentalizing network, and that the ability to distinguish between self and other mental states is modulated by a functionally interactive dorsal and ventral attention/selection systems at the temporoparietal junction and the anterior cingulate cortex; and (3) ToM functioning is dependent on the integrity of the dopaminergic and serotonergic systems which are primarily engaged in the maintenance and application processes of represented mental states. In addition to discussing the mechanisms involved in mentalizing in terms of its component processes, we discuss the model's implications to pathologies that variably impact one's ability to represent, attribute and apply mental states.
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Lesion and neuroimaging studies have implicated the medial frontal lobes as playing an important role in our ability to predict other people's behavior by attributing to them mental states, such as beliefs, intention and emotion (termed "Theory of Mind"; ToM). However, recent studies have challenged these findings by highlighting the role of the temporal-parietal junction (TPJ) in ToM. In the present study, we tested the hypothesis that the ventromedial (VM) prefrontal cortex plays a unique role in affective ToM reasoning rather than a general role in ToM. We compared the performance of patients with lesions localized either in the VM, dorsolateral, TPJ, or superior parietal to healthy controls, with a battery of naturalistic affective and cognitive ToM stories (about false beliefs, false attribution, irony and lies). Patients with VM damage were impaired at providing appropriate mental state explanations for the affective ToM stories, compared to healthy controls and patients with posterior damage. In the VM group, performance in the affective ToM was significantly impaired as compared to cognitive ToM stories. Furthermore, in the VM group, ratings of levels of emotionality of each story suggested that levels of affective load correlated with number of errors in the stories, indicating that the more the emotional load involved in the story the greater the difficulty posed for the subjects in this group.
Article
Theory of Mind (ToM) is the ability to attribute thoughts, intentions and beliefs to others. This involves component processes, including cognitive perspective taking (cognitive ToM) and understanding emotions (affective ToM). This study assessed the distinction and overlap of neural processes involved in these respective components, and also investigated their development between adolescence and adulthood. While data suggest that ToM develops between adolescence and adulthood, these populations have not been compared on cognitive and affective ToM domains. Using fMRI with 15 adolescent (aged 11-16 years) and 15 adult (aged 24-40 years) males, we assessed neural responses during cartoon vignettes requiring cognitive ToM, affective ToM or physical causality comprehension (control). An additional aim was to explore relationships between fMRI data and self-reported empathy. Both cognitive and affective ToM conditions were associated with neural responses in the classic ToM network across both groups, although only affective ToM recruited medial/ventromedial PFC (mPFC/vmPFC). Adolescents additionally activated vmPFC more than did adults during affective ToM. The specificity of the mPFC/vmPFC response during affective ToM supports evidence from lesion studies suggesting that vmPFC may integrate affective information during ToM. Furthermore, the differential neural response in vmPFC between adult and adolescent groups indicates developmental changes in affective ToM processing.
Article
Human social behavior develops under the influence of genetic, environmental, and cultural factors. Social cognition comprises our ability to understand and respond appropriately to other people's social approaches or responses. The concept embraces self-knowledge and theory of mind, or the ability to think about emotions and behavior from the perspective of another person. The neuropeptides oxytocin (OT) and vasopressin (AVP) are now known to play an important role, affecting individual differences in parenting behavior, social recognition, and affiliative behaviors. The processes of social cognition are also supported by reward circuitry, underpinned by the dopaminergic neurotransmitter system. Reward processes build social relationships, in parenting and pair-bonding, and influence social interactions that require trust, or display altruism. The impact of emotional regulation upon social behavior, including mood and anxiety, is also mediated through the serotonergic system. Variation in activity of serotonergic networks in the brain influences emotional responsivity, including subjective feelings, physiological responses, emotional expressions, and the tendency to become engaged in action as a consequence of a feeling state. Genetic variation in the receptors associated with OT, AVP, dopamine, and serotonin has been intensively studied in humans and animal models. Recent findings are building an increasingly coherent picture of regulatory mechanisms.
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Representational theory of mind (RTM) development follows a universal developmental timetable whereby major advances in reasoning about mental representations occur between the ages of 3 and 5 years old. This progression appears to be only absent in the case of specific neurodevelopmental impairments, such as autism. Taken together, this suggests that neuromaturational factors may play a role in RTM development. Recent EEG work has shown that one neuromaturational factor pacing this universal developmental timetable is the functional maturation of medial prefrontal cortex. The neurotransmitter dopamine (DA) is thought to play a crucial role in typical frontal lobe development. Therefore, the goal of the present study was to investigate the role that DA may play in RTM development. Ninety-one 48-62-month olds were given a battery of RTM tasks along with EEG measurement. EEG recordings were analyzed for eyeblinks, a reliable indicator of DA functioning, and we calculated their average eyeblinks per minute (EBR). Regression analyses showed that EBR was associated with RTM after controlling for children's performance on a Stroop-like measure, language ability, gender, and age. These findings provide evidence that DA functioning is associated with RTM in the preschool years, and are discussed with respect to how DA might provide a mechanism that helps to account for both neurobiological and experiential factors that are known to affect the timetable of preschoolers' RTM development.
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Bariatric surgery is efficacious for the treatment of severe obesity; however, little empirical research exists describing the demographic, psychosocial, and cognitive characteristics of patients presenting for the surgery. One hundred and sixty-nine morbidly obese patients seeking bariatric surgery underwent a presurgical psychological assessment, including cognitive testing. Morbidly obese individuals seeking bariatric surgery were similar in education, income status, and IQ compared with normative data. IQ was average, did not correlate with body mass index, and reflected a normal distribution. As a group, bariatric surgery patients endorsed minimal levels of depression and low levels of psychopathology. Obese individuals did demonstrate specific cognitive deficits on tests of executive function (e.g., problem solving and planning) when compared with normative data. This data suggests that bariatric surgery patients differ very little from other surgical populations on most demographic and psychosocial variables. The data does provide evidence for specific cognitive deficits in the area of executive functions at baseline in morbidly obese adults seeking bariatric surgery.
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Stress and emotional brain networks foster eating behaviors that can lead to obesity. The neural networks underlying the complex interactions among stressors, body, brain and food intake are now better understood. Stressors, by activating a neural stress-response network, bias cognition toward increased emotional activity and degraded executive function. This causes formed habits to be used rather than a cognitive appraisal of responses. Stress also induces secretion of glucocorticoids, which increases motivation for food, and insulin, which promotes food intake and obesity. Pleasurable feeding then reduces activity in the stress-response network, reinforcing the feeding habit. These effects of stressors emphasize the importance of teaching mental reappraisal techniques to restore responses from habitual to thoughtful, thus battling stress-induced obesity.
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The relationship between developmental obesity and emotional problems has been particularly studied by Bruch. According to this author, the main reason for early-onset obesity has to be found in the difficulty of some mothers to adequately distinguish between emotional manifestations and the child's real need for food. In this paper an experiment was carried out in order to test the relationship between developmental obesity and poor ability to recognize facial expressions of some basic emotions. A group of 20 mothers whose children suffered from serious early-onset obesity (experimental group) and another group of 20 mothers, whose children had slight overweight problems arising long after the first year of life (control group), were tested. Both mothers and their children were asked to recognize a set of facial expressions of emotions. 42 slides of facial expressions of emotions (anger, sadness, disgust, surprise, fear, happiness and neutral faces) were presented to subjects who were asked to mark on an answer sheet the name of the emotion expressed by the actor's face. A significant difference between the groups was found: a larger number of errors in the recognition of facial expression of emotions was made by mothers and their children in the experimental group. Furthermore a positive linear correlation between the number of errors made by the mothers and that made by their children was present. The findings do support Bruch's clinical observations. Further studies concerning other emotional signs (either nonverbal or verbal) are needed in order to assess the importance of emotional decoding difficulties in developmental obesity.
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Several recent studies have demonstrated a developmental link, in the age range of 3-5 years, between the acquisition of a 'theory of mind' and self control. In this review, we consider the existence of such a link in assessing five competing theoretical hypotheses that might help us to understand the nature of this developmental advance: (1) executive control depends on theory of mind; (2) theory of mind development depends on executive control; (3) the relevant theory of mind tasks require executive control; (4) both kinds of task require the same kind of embedded conditional reasoning; (5) theory of mind and executive control involve the same brain region. We briefly describe these theoretical accounts and evaluate them in the light of existing empirical evidence. At present, only account (3) can be ruled out with some confidence.
Article
Since its discovery in 1958 (Axelrod and Tomchick 1958), catechol-O-methyltransferase (COMT) has been an important enzyme in catecholamine biochemistry and pharmacology and, more recently, in genetic mechanisms of variation in catechol metabolism and its clinical implications. COMT catalyzes the transfer of a methyl group from S-adenosyl-methionine (SAM) to a hydroxyl group on a catechol nucleus (e.g., dopamine, norepinephrine, or catechol estrogen) (Weinshilboum et al. 1999). Genetic variation in COMT has been associated with diverse clinical phenotypes, from anxiety to estrogen-related cancer (Enoch et al. 2003; Ahsan et al. 2004), and it has been studied particularly extensively in relation to risk for schizophrenia (Harrison and Weinberger 2004). The COMT gene is located in chromosome 22q11, one of the principal loci linked to schizophrenia (Badner and Gershon 2002), and in the DiGeorge–velocardiofacial syndrome hemideletion. There are two promoters, P1 and P2, (Tenhunen et al. 1993), that control transcription of two different mRNAs. A longer mRNA from the P2 promoter encodes mainly a membrane-bound COMT (MB-COMT), and a shorter mRNA from the P1 promoter encodes a soluble COMT (S-COMT). The MB-COMT has higher substrate affinity but lower catalytic activity than S-COMT (Lotta et al. 1995). The MB-COMT is predominantly expressed in brain neurons (Matsumoto et al. 2003), and S-COMT is predominantly expressed in other tissues, such as liver, blood, and kidney (Tenhunen et al. 1993; Lundstrom et al. 1995). Human COMT contains a common functional polymorphism, a G→A substitution in exon 4 that alters the amino acid codon at position 108 (Val108Met) (rs165688) in S-COMT or position 158 (Val158Met) in the MB-COMT protein (Lotta et al. 1995). This common polymorphism has been shown to result in a significant change in enzyme activity in peripheral blood and in liver (Scanlon et al. 1979; Weinshilboum and Dunnette 1981; Boudikova et al. 1990; Lotta et al. 1995).