An fMRI study of self-reflection about body image: Sex differences

Sex differences in regional gray matter density in pre-adolescent binge eating disorder: a voxel-based morphometry study

BACKGROUND

Binge eating disorder (BED) is a pernicious psychiatric disorder which is linked with broad medical and psychiatric morbidity, and obesity. While BED may be characterized by altered cortical morphometry, no evidence to date examined possible sex-differences in regional gray matter characteristics among those with BED. This is especially important to consider in children, where BED symptoms often emerge coincident with rapid gray matter maturation.

METHODS

Pre-adolescent, 9-10-year old boys (N = 38) and girls (N = 33) with BED were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development Study. We investigated sex differences in gray matter density (GMD) via voxel-based morphometry. Control sex differences were also assessed in age and body mass index and developmentally matched control children (boys N = 36; girls N = 38). Among children with BED, we additionally assessed the association between dorsolateral prefrontal (dlPFC) GMD and parent-reported behavioral approach and inhibition tendencies.

RESULTS

Girls with BED uniquely demonstrate diffuse clusters of greater GMD (p < 0.05, Threshold Free Cluster Enhancement corrected) in the (i) left dlPFC (p = 0.003), (ii) bilateral dmPFC (p = 0.004), (iii) bilateral primary motor and somatosensory cortex (p = 0.0003) and (iv) bilateral precuneus (p = 0.007). Brain-behavioral associations suggest a unique negative correlation between GMD in the left dlPFC and behavioral approach tendencies among girls with BED.

CONCLUSIONS

Early-onset BED may be characterized by regional sex differences in terms of its underlying gray matter morphometry.

The relationship between brain neural correlates, self-objectification, and interoceptive sensibility

Interoceptive sensibility refers to the tendency to focus on internal bodily states and the capacity to detect them. As the subjective dimension of interoception, interoceptive sensibility plays a key role in individuals' health. Self-objectification, a process by which individuals tend to adopt a third-person's perspective of their physical self, leads to decreased interoceptive sensibility. However, few studies regarding the neural basis of interoceptive sensibility and the underlying mechanism of the relationship between self-objectification and interoceptive sensibility have been conducted. In this study, we assessed the resting-state brain activity (fractional amplitude of low-frequency fluctuation, fALFF) and connectivity (resting-state functional connectivity, RSFC) of 442 college students. Whole-brain correlation analyses revealed that a higher level of interoceptive sensibility was linked to higher fALFF in the right inferior frontal gyrus (IFG) and left cerebellum and to lower fALFF in the left paracentral lobule and left superior/middle temporal gyrus. Interoceptive sensibility also was negatively associated with the RSFC between the right IFG and the right secondary somatosensory cortex (S2) and the right IFG and the ventral premotor cortex (VPC). These brain regions and connections are mainly responsible for switching attention to internal/external information and processing body-related somatosensory as well as sensory information. Mediation analyses suggested that the fALFF of the right IFG and the RSFC of IFG-S2 and IFG-VPC mediated the relationship between self-objectification and interoceptive sensibility. Overall, these results suggest that the IFG may be the neural marker of interoceptive sensibility and reveal several potential mediation models of the relationship between brain neural correlates and self-objectification and interoceptive sensibility.

Giving a Body a Different Face—How Men and Women Evaluate Their Own Body vs. That of Others

Eating disorders affect women more than men. Women reportedly dislike their body shape more and appreciate it less than do men. One factor influencing body image might be the application of different standards for oneself than for other people when evaluating bodies. To investigate this possibility, we determined whether the application of double standards is different between men and women. We presented 57 women and 54 men (aged 18–30 and of average weight) with pictures of their own bodies and pictures of average weight, overweight, and “ideal” bodies attached to the participants’ own face and to another person’s face. Participants were instructed to evaluate their emotional reaction to the pictures and then rate the various pictures on aspects of attractiveness, body fat, and muscle mass. The degree of the double standard was defined as the difference between ratings of what appeared to be one’s own body and what appeared to be someone else’s according to the presented face. The analyses revealed, firstly, that both genders applied self-deprecating double standards when viewing overweight and average-weight bodies. Women, but not men, also showed self-deprecating double standards when viewing the ideal body and their own body. By contrast, men applied fewer double standards when viewing the ideal body and self-enhancing double standards when viewing their own body. The study suggests that young, average-weight men are more or less satisfied with their own bodies, whereas young, average-weight women tend to apply a stricter standard for themselves than for others, thus devaluing their own bodies. This vulnerability to body image is hypothesized as contributing to the prevalence of eating disorders in women.

Meta-Analysis of the RDoC Social Processing Domain across Units of Analysis in Children and Adolescents

OBJECTIVE

This meta-analysis advances a framework to understand correspondence among units of analysis of the social processing construct within Research Domain Criteria (RDoC).

METHOD

As requested for this special issue, eligible studies cited an RDoC-initiative paper or mentioned RDoC in the abstract, title, or keywords were empirical and peer reviewed, and described a correlation or regression analysis (r, β, or odds ratio) between two different units of analysis in the social processing domain in youth. We examined the frequency (descriptive statistics) and magnitude of correspondence between unit-pairs (random effects models), and predefined moderators (meta-regression).

RESULTS

Eight of the twenty-eight possible unit-by-unit pairs were identified, with subjective-by-behavior units being the most common. Of those, only subjective-by-circuit had significant correspondence between units. Moderator analysis revealed that the age and diagnosis of generalized anxiety disorder moderated correspondence between subjective-by-circuit units of analysis, and that a diagnosis of autism spectrum disorder moderated correspondence between subjective-by-gene units of analysis. Younger ages and inclusion of either diagnostic group reduced correspondence.

CONCLUSIONS

These findings indicate that the RDoC initiative has generated limited research within the social processing domain across units of analysis in youth to date. Moreover, National Institute of Mental Health (NIMH)-funded studies do not appear to be biased toward supporting the RDoC framework. However, the limited number of included studies precludes the generalizability of these findings and underscores the need for further research. Despite this, results suggest that the NIMH model for providing standard batteries of measurement tools may effectively reduce spurious correlations between subjective-by-behavior units of analysis.

Gender Differences in Body Evaluation: Do Men Show More Self-Serving Double Standards Than Women?

Generally speaking, compared to women, men are less dissatisfied with their own body and consider themselves to be better-looking and less overweight. So far, however, it is unclear whether these divergent body ratings arise from the application of double standards. With the present study, we examined whether men apply different standards to their own body than to other men’s bodies and whether they differ from women in this regard. To this aim, we presented n = 104 women and n = 93 men with pictures of thin, average-weight, overweight, athletic and hypermuscular male and female bodies on a computer screen. To manipulate identification, we showed the bodies of the respective participant’s gender once with the participant’s own face and once with the face of another person. Identity cues, such as faces, might activate different body schemata, which influence body ratings and thus lead to the application of double standards. Participants were instructed to rate their emotional reaction to the bodies according to valence and arousal, and to rate the bodies with respect to attractiveness, body fat, and muscle mass. The application of double standards was determined by calculating the difference between the rating of a body presented with the participant’s face and the rating of the same body presented with another person’s face. Both women and men showed self-deprecating double standards in valence, body attractiveness, body fat and muscle mass for the overweight body. Men also revealed self-deprecating double standards for the thin, average-weight and hypermuscular bodies, but evaluated the athletic body as more attractive and with a higher positive feeling when it was presented with their own face. Women did not show any self-serving double standards and showed fewer self-deprecating double standards than men. The results indicate that men devalue non-ideal bodies and upvalue ideal bodies when they are self-related, whereas women more rate in a fair-minded manner. Thus, in contrast to women, an advantage for men may be that they are able to self-enhance in the case of desirable bodies. This ability to self-enhance regarding desirable features might be beneficial for men’s self-worth and body satisfaction.

Reasons for lithium discontinuation in men and women with bipolar disorder: a retrospective cohort study

BACKGROUND

Lithium remains first choice as maintenance treatment for bipolar affective disorder. Yet, about half of all individuals may stop their treatment at some point, despite lithium's proven benefits concerning the prevention of severe affective episodes and suicide.

METHODS

Retrospective cohort study in the Swedish region of Norrbotten into the causes of lithium discontinuation. The study was set up to (1) test whether patients with bipolar affective disorder or schizoaffective disorder, treated with lithium maintenance therapy, were more likely to discontinue lithium because of adverse effects than lack of therapeutic effectiveness, (2) explore gender differences, (3) understand the role of diagnosis and (4) identify who, patient or doctor, took the initiative to stop lithium. Review of medical records for all episodes of lithium discontinuation that had occurred between 1997 and 2013 with the intent to stop lithium for good.

RESULTS

Of 873 patients treated with lithium, 54% discontinued lithium, corresponding to 561 episodes of lithium discontinuation. In 62% of episodes, lithium was discontinued due to adverse effects, in 44% due to psychiatric reasons, and in 12% due to physical reasons interfering with lithium treatment. The five single most common adverse effects leading to lithium discontinuation were diarrhoea (13%), tremor (11%), polyuria/polydipsia/diabetes insipidus (9%), creatinine increase (9%) and weight gain (7%). Women were as likely as men to take the initiative to stop lithium, but twice as likely to consult a doctor before taking action (p < 0.01). Patients with type 1 BPAD or SZD were more likely to discontinue lithium than patients with type 2 or unspecified BPAD (p < 0.01). Patients with type 1 BPAD or SZD were more likely to refuse medication (p < 0.01). Conversely, patients with type 2 or unspecified BPAD were three times as likely to discontinue lithium for lack or perceived lack of effectiveness (p < 0.001).

CONCLUSIONS

Stopping lithium treatment is common and occurs mostly due to adverse effects. It is important to discuss potential adverse effects with patients before initiation and continuously during lithium treatment, to reduce the frequency of potentially unnecessary discontinuations.

My Body Looks Like That Girl's: Body Mass Index Modulates Brain Activity during Body Image Self-Reflection among Young Women

Body image distress or body dissatisfaction is one of the most common consequences of obesity and overweight. We investigated the neural bases of body image processing in overweight and average weight young women to understand whether brain regions that were previously found to be involved in processing self-reflective, perspective and affective components of body image would show different activation between two groups. Thirteen overweight (O-W group, age = 20.31±1.70 years) and thirteen average weight (A-W group, age = 20.15±1.62 years) young women underwent functional magnetic resonance imaging while performing a body image self-reflection task. Among both groups, whole-brain analysis revealed activations of a brain network related to perceptive and affective components of body image processing. ROI analysis showed a main effect of group in ACC as well as a group by condition interaction within bilateral EBA, bilateral FBA, right IPL, bilateral DLPFC, left amygdala and left MPFC. For the A-W group, simple effect analysis revealed stronger activations in Thin-Control compared to Fat-Control condition within regions related to perceptive (including bilateral EBA, bilateral FBA, right IPL) and affective components of body image processing (including bilateral DLPFC, left amygdala), as well as self-reference (left MPFC). The O-W group only showed stronger activations in Fat-Control than in Thin-Control condition within regions related to the perceptive component of body image processing (including left EBA and left FBA). Path analysis showed that in the Fat-Thin contrast, body dissatisfaction completely mediated the group difference in brain response in left amygdala across the whole sample. Our data are the first to demonstrate differences in brain response to body pictures between average weight and overweight young females involved in a body image self-reflection task. These results provide insights for understanding the vulnerability to body image distress among overweight or obese young females.

Present-self, past-self and the close-other: neural correlates of assigning trait adjectives to oneself and others

Information regarding the past-self may be viewed as information referring to other people. However, evidence supporting this notion at the neural level is rather sparse and it remains unclear whether the past-self is processed like any 'other' or like the close-other only. The aim of this event-related potential study was to investigate this issue. A reflection task requiring evaluation of positive and negative trait adjectives with respect to present- and past-self, a close-other and a famous person was applied. We hypothesized that the past-self and close-other conditions would share their neural underpinnings. The process of reflection on the past-self and close-other was indeed associated with similar mean amplitudes of the late positive component (LPC), whereas in the case of the past-self vs. famous person comparison LPC was significantly enhanced for the past-self. Analogous effects were observed when LPC was calculated for trials with traits judged as either suitable or unsuitable to describe a person who was the target of reflection. Thus, these findings suggest that the processing of information related to the past-self resembles processing of information related to a personally relevant other. Moreover, sex-differences were observed in reaction times and LPC amplitudes for responses reflecting the positivity bias.

An fMRI investigation of emotional processing of body shape in bulimia nervosa

OBJECTIVE

Cognitive-behavioral theories of eating disorder etiology emphasize the role of body-oriented self-schemas. Examination of brain regions associated with self-referencing, such as medial prefrontal cortex (mPFC), during processing of body-related stimuli can thus be utilized to evaluate such theories.

METHOD

Twelve women with bulima nervosa (BN) and 12 comparison women underwent functional brain imaging while viewing images of women with either thin or overweight bodies in a self-referencing context.

RESULTS

For thin bodies, there was no significant mPFC activation for either group. For overweight bodies, mPFC activation was significantly greater for BN patients, with a focus in subregions associated with emotional processing.

DISCUSSION

These findings are consistent with cognitive models of eating disorders which posit that negative body-related stimuli are more central to self-schemas and more emotionally provocative in persons with eating disorders, lending support to treatment and prevention interventions that emphasize body overvaluation as a primary target of change.

Predicting ideal body mass index: what does clothing size have to do with it?

This study examined demographic and anthropometric variables as predictors of ideal body mass index (BMI) from cross-sectional, archival, self-reported data from the Psychology of Size Survey of 4014 U.S. residents collected in 2007. As hypothesized, ideal BMI can be predicted by a within gender hierarchical multiple regression analysis with the predictor variables of age, number of clothing sizes from ideal size, and current BMI; these variables account for 54.1% of variance in women's ideal BMI and 65.5% of variance in men's ideal BMI. Findings also demonstrated a logarithmic relationship between current BMI and ideal BMI, with increasing variance in ideal BMI for individuals with high current BMIs. These findings evidence the strong role of current body characteristics in the formation of ideals. Understanding how individuals conceptualize body ideals can inform researchers and practitioners alike, as this evidence has important implications related to both medical and psychological health.