Hippocampal volume and cognitive function in anorexia nervosa

Event-related potentials during recognition of semantic and pictorial food stimuli in patients with anorexia nervosa and healthy controls with varying internal states of hunger

OBJECTIVE

To elucidate maladaptive central processing of food cues during recognition tasks in anorexia nervosa (AN), while considering influences of nutritional preload and presentation modality (word versus picture).

METHODS

Event-related potentials to food-related word and pictorial stimuli were assessed during recognition tasks in 16 patients with AN, 16 control participants with food intake before the study, and 16 control participants with a fasting period before the study.

RESULTS

Patients with AN showed a P3b amplitude reduction especially at the midline parietal site compared with satiated controls (5.7 [standard deviation = 3.3] versus 8.7 [3.1] μV, p < .03). Subtle recognition deficits in patients with AN were indicated by smaller "old/new" effects compared with satiated (p = .049) and fasting controls (p < .003) for pictorial stimuli. Hunger-modulated enhanced old/new effects for food pictures compared with neutral pictorial stimuli could be observed in fasting controls only (2.7 [2.6] versus 0.8 [2.2] μV, p < .01).

CONCLUSIONS

The presented data provide evidence for a midline parietal P3b amplitude reduction in patients with AN, which might point to reduced network activation in AN even during satiety. Observed subtle recognition deficits either represent a stable trait characteristic or a "scar" effect of chronic starvation that may play a role in the development and/or persistence of the disorder.

Neuroscience and eating disorders: the allocentric lock hypothesis

Evidence from psychology and neuroscience indicates that our spatial experience, including the bodily one, involves the integration of different sensory inputs within two different reference frames egocentric (body as reference of first-person experience) and allocentric (body as object in the physical world). Even if functional relations between these two frames are usually limited, they influence each other during the interaction between long- and short-term memory processes in spatial cognition. If, for some reasons, this process is impaired, the egocentric sensory inputs are no more able to update the contents of the allocentric representation of the body: the subject is locked to it. In the presented perspective, subjects with eating disorders are locked to an allocentric representation of their body, stored in long-term memory (allocentric lock). A significant role in the locking may be played by the medial temporal lobe, and in particular by the connection between the hippocampal complex and amygdala. The differences between exogenous and endogenous causes of the lock may also explain the difference between bulimia nervosa and anorexia nervosa.

Restraint of appetite and reduced regional brain volumes in anorexia nervosa: a voxel-based morphometric study

BACKGROUND

Previous Magnetic Resonance Imaging (MRI) studies of people with anorexia nervosa (AN) have shown differences in brain structure. This study aimed to provide preliminary extensions of this data by examining how different levels of appetitive restraint impact on brain volume.

METHODS

Voxel based morphometry (VBM), corrected for total intracranial volume, age, BMI, years of education in 14 women with AN (8 RAN and 6 BPAN) and 21 women (HC) was performed. Correlations between brain volume and dietary restraint were done using Statistical Package for the Social Sciences (SPSS).

RESULTS

Increased right dorsolateral prefrontal cortex (DLPFC) and reduced right anterior insular cortex, bilateral parahippocampal gyrus, left fusiform gyrus, left cerebellum and right posterior cingulate volumes in AN compared to HC. RAN compared to BPAN had reduced left orbitofrontal cortex, right anterior insular cortex, bilateral parahippocampal gyrus and left cerebellum. Age negatively correlated with right DLPFC volume in HC but not in AN; dietary restraint and BMI predicted 57% of variance in right DLPFC volume in AN.

CONCLUSIONS

In AN, brain volume differences were found in appetitive, somatosensory and top-down control brain regions. Differences in regional GMV may be linked to levels of appetitive restraint, but whether they are state or trait is unclear. Nevertheless, these discrete brain volume differences provide candidate brain regions for further structural and functional study in people with eating disorders.

Structural magnetic resonance imaging in eating disorders: a systematic review of voxel-based morphometry studies

This systematic review summarises and critically appraises the literature on structural magnetic resonance imaging in people with a current or past eating disorder. Studies using voxel-based morphometry image analysis were included. Ten studies reported on a total of 236 people with a current or past eating disorder and 257 healthy controls. Sample heterogeneity prohibited a meta-analytic approach. The findings do not unequivocally indicate grey or white matter volume abnormalities in people with an eating disorder. Nevertheless, these preliminary data suggest that, compared with healthy controls, people with anorexia nervosa have decreased grey matter in a range of brain regions and that those with bulimia nervosa have increased grey matter volumes in frontal and ventral striatal areas. Research in the recovery phase and longitudinal studies suggest that potential brain tissue abnormalities may recover with clinical improvement. Overall, as the available data are inconclusive, further efforts in this field are warranted.

Grey matter abnormalities within cortico-limbic-striatal circuits in acute and weight-restored anorexia nervosa patients

Functional disturbances within cortico-striatal control systems have been implicated in the psychobiology (i.e. impaired cognitive-behavioral flexibility, perfectionist personality) of anorexia nervosa. The aim of the present study was to investigate the morphometry of brain regions within cortico-striatal networks in acute anorexia nervosa (AN) as well as long-term weight-restored anorexia nervosa (AN-WR) patients. A total of 39 participants: 12 AN, 13 AN-WR patients, and 14 healthy controls (HC) underwent high-resolution, T1-weighted magnetic resonance imaging (MRI), a cognitive-behavioral flexibility task, and a psychometric assessment. Group differences in local grey matter volume (GMV) were analyzed using whole brain voxel-based morphometry (VBM) and brain-atlas based automatic volumetry computation (IBASPM). Individual differences in total GMV were considered as a covariate in all analyses. In the regional brain morphometry, AN patients, as compared to HC, showed decreased GMVs (VBM and volumetry) in the anterior cingulate cortex (ACC), the supplementary motor area (SMA), and in subcortical regions (amygdala, putamen: VBM only). AN-WR compared to HC showed decreased GMV (VBM and volumetry) in the ACC and SMA, whereas GMV of the subcortical region showed no differences. The findings of the study suggest that structural abnormalities of the ACC and SMA were independent of the disease stage, whereas subcortical limbic-striatal changes were state dependent.

Memory performance in acute and weight-restored anorexia nervosa patients

BACKGROUND

Anorexia nervosa (AN), at the stage of starvation and emaciation, is characterized by abnormalities in cognitive function, including memory performance. It is unclear whether memory impairment persists or is reversible following weight restoration, and whether memory function differs between AN subtypes. The aim of the present study was to investigate general memory performance in currently ill and fully weight-restored patients of different AN subtypes.

METHOD

Memory performance was assessed using the Wechsler Memory Scale-Revised (WMS-R) in a total of 99 participants, including 34 restricting-type AN patients (AN-RESTR), 19 binge-eating/purging-type AN patients (AN-PURGE), 16 weight-restored AN patients (AN-W-R) and 30 healthy controls (CONTROL). Cognitive evaluation included a battery of standardized neuropsychological tasks for validating the findings on memory function.

RESULTS

Deficits were found with respect to immediate and delayed story recall in currently ill AN patients irrespective of AN subtype. These deficits persisted in weight-restored AN patients. Currently ill and weight-restored AN patients did not differ significantly from healthy controls with respect to working memory or other measures of neuropsychological functioning.

CONCLUSIONS

The findings suggest that impaired memory performance is either a stable trait characteristic or a scar effect of chronic starvation that may play a role in the development and/or persistence of the disorder.

Estimated intelligence quotient in anorexia nervosa: a systematic review and meta-analysis of the literature

BACKGROUND

It has been hypothesised that people with anorexia nervosa have a higher intelligence quotient (IQ) level than the general population. The purpose of this review was to systematically appraise the research into reported IQ levels in people with anorexia nervosa.

METHODS

A search using the terms intelligence quotient, IQ, intelligence, cognition, eating disorders and anorexia was conducted in electronic databases only.

RESULTS

In all, 30 peer-reviewed studies written in English that used well established measures of intelligence quotient (the National Adult Reading Test and Wechsler Intelligence Scales) were identified. This review established that people with anorexia nervosa score 10.8 units and 5.9 units above the average intelligence quotient of the normative population on the National Adult Reading Test and Wechsler Intelligence Scales, respectively. An association was found between Body Mass Index and intelligence quotient, as measured by the National Adult Reading Test.

CONCLUSIONS

More studies including other eating disorder categories and recovered people are needed to explore important questions regarding the role of the intelligence quotient in treatment response.

Structural neuroplasticity in the sensorimotor network of professional female ballet dancers

Evidence suggests that motor, sensory, and cognitive training modulates brain structures involved in a specific practice. Functional neuroimaging revealed key brain structures involved in dancing such as the putamen and the premotor cortex. Intensive ballet dance training was expected to modulate the structures of the sensorimotor network, for example, the putamen, premotor cortex, supplementary motor area (SMA), and the corticospinal tracts. We investigated gray (GM) and white matter (WM) volumes, fractional anisotropy (FA), and mean diffusivity (MD) using magnetic resonance-based morphometry and diffusion tensor imaging in 10 professional female ballet dancers compared with 10 nondancers. In dancers compared with nondancers, decreased GM volumes were observed in the left premotor cortex, SMA, putamen, and superior frontal gyrus, and decreased WM volumes in both corticospinal tracts, both internal capsules, corpus callosum, and left anterior cingulum. FA was lower in the WM underlying the dancers' left and right premotor cortex. There were no significant differences in MD between the groups. Age of dance commencement was negatively correlated with GM and WM volume in the right premotor cortex and internal capsule, respectively, and positively correlated with WM volume in the left precentral gyrus and corpus callosum. Results were not influenced by the significantly lower body mass index of the dancers. The present findings complement the results of functional imaging studies in experts that revealed reduced neural activity in skilled compared with nonskilled subjects. Reductions in brain activity are accompanied by local decreases in GM and WM volumes and decreased FA.

Voxel-based morphometry in eating disorders: correlation of psychopathology with grey matter volume

Twenty-nine adult female patients with eating disorders (17 with bulimia nervosa, 12 with restrictive anorexia nervosa) were compared with 18 age-matched female healthy controls, using voxel-based morphometry. Restrictive anorexia nervosa patients showed a decrease of grey matter, particularly affecting the anterior cingulate cortex, frontal operculum, temporoparietal regions and the precuneus. By contrast, patients with bulimia nervosa did not differ from healthy controls. A positive correlation of "drive for thinness" and grey matter volume of the right inferior parietal lobe was found for both eating disorder groups. The strong reduction of grey matter volume in adult patients with restrictive anorexia nervosa is in line with results of adolescent patients. Contrary to other studies, this first voxel-based morphometry report of bulimic patients did not find any structural abnormalities. The inferior parietal cortex is a critical region for sensory integration of body and spatial perception, and the correlation of "drive for thinness" with grey matter volume of this region points to a neural correlate of this core psychopathological feature of eating disorders.

Refeeding syndrome: treatment considerations based on collective analysis of literature case reports

Refeeding syndrome (RFS) represents a group of clinical findings that occur in severely malnourished individuals undergoing nutritional support. Cardiac arrhythmias, multisystem organ dysfunction, and death are the most severe symptoms observed. As the cachectic body attempts to reverse its adaptation to the starved state in response to the nutritional load, symptoms result from fluid and electrolyte imbalances, with hypophosphatemia playing a central role. Because guidelines for feeding the malnourished patient at risk for refeeding syndrome is scarce, we have provided management recommendations based on the knowledge derived from a collection of reported English literature cases of the RFS. A MEDLINE search using keywords including "refeeding syndrome," "RFS," and "refeeding hypophosphatemia" was performed. References from initial cases were utilized for more literature on the subject. We have emphasized the continued importance of managing patients at risk for RFS, compared how management of the severely malnourished patients have evolved over time, and provided comprehensive clinical guidelines based on the sum of experience documented in the case reports for the purpose of supplementing the guidelines available. Based on our review, the most effective means of preventing or treating RFS were the following: recognizing the patients at risk; providing adequate electrolyte, vitamin, and micronutrient supplementation; careful fluid resuscitation; cautious and gradual energy restoration; and monitoring of critical laboratory indices.

Structural neuroplasticity in the sensorimotor network of professional female ballet dancers

Evidence suggests that motor, sensory, and cognitive training modulates brain structures involved in a specific practice. Functional neuroimaging revealed key brain structures involved in dancing such as the putamen and the premotor cortex. Intensive ballet dance training was expected to modulate the structures of the sensorimotor network, for example, the putamen, premotor cortex, supplementary motor area (SMA), and the corticospinal tracts. We investigated gray (GM) and white matter (WM) volumes, fractional anisotropy (FA), and mean diffusivity (MD) using magnetic resonance-based morphometry and diffusion tensor imaging in 10 professional female ballet dancers compared with 10 nondancers. In dancers compared with nondancers, decreased GM volumes were observed in the left premotor cortex, SMA, putamen, and superior frontal gyrus, and decreased WM volumes in both corticospinal tracts, both internal capsules, corpus callosum, and left anterior cingulum. FA was lower in the WM underlying the dancers' left and right premotor cortex. There were no significant differences in MD between the groups. Age of dance commencement was negatively correlated with GM and WM volume in the right premotor cortex and internal capsule, respectively, and positively correlated with WM volume in the left precentral gyrus and corpus callosum. Results were not influenced by the significantly lower body mass index of the dancers. The present findings complement the results of functional imaging studies in experts that revealed reduced neural activity in skilled compared with nonskilled subjects. Reductions in brain activity are accompanied by local decreases in GM and WM volumes and decreased FA.

Evaluation of autophagy using mouse models of brain injury

Autophagy is a homeostatic, carefully regulated, and dynamic process for intracellular recycling of bulk proteins, aging organelles, and lipids. Autophagy occurs in all tissues and cell types, including the brain and neurons. Alteration in the dynamics of autophagy has been observed in many diseases of the central nervous system. Disruption of autophagy for an extended period of time results in accumulation of unwanted proteins and neurodegeneration. However, the role of enhanced autophagy after acute brain injury remains undefined. Established mouse models of brain injury will be valuable in clarifying the role of autophagy after brain injury and are the topic of discussion in this review.

Quantitative evidence for distinct cognitive impairment in anorexia nervosa and bulimia nervosa

It is generally agreed that at least some aspects of abnormal eating behaviour is indeed due in part to disordered cognition. The accumulated literature illustrates cognitive impairment in patients with anorexia nervosa (AN) and bulimia nervosa (BN). Yet beyond being inconsistent, these independent studies also do not reveal the magnitude of impairment within and across studies and fail to give due consideration to the magnitude of impairment so as to understand the severity and breadth of impairment and/or differences in cognitive profiles between patients with AN and BN. Hence, the present review on the subject sought to articulate the magnitude of cognitive impairment in patients with AN and BN by quantitatively synthesizing the existing literature using meta-analytic methodology. The results demonstrate modest evidence of cognitive impairment specific to AN and BN that is related to body mass index in AN in terms of its severity, and is differentially impaired between disorders. Together, these results suggest that disturbed cognition is figural in the presentation of eating disorders and may serve to play an integral role in its cause and maintenance. Implications of these findings with respects to future research are discussed.

Are anorexia nervosa and bulimia nervosa separate disorders? Challenging the 'transdiagnostic' theory of eating disorders

BACKGROUND

Anorexia nervosa (AN) and bulimia nervosa (BN) are classified as separate and distinct clinical disorders. Recently, there has been support for a transdiagnostic theory of eating disorders, which would reclassify them as one disorder.

OBJECTIVE

To determine whether AN and BN are a single disorder with one cause or separate disorders with different causes.

METHOD

Hill's Criteria of Causation were used to test the hypothesis that AN and BN are one disorder with a single cause. Hill's Criteria of Causation demand that the minimal conditions are needed to establish a causal relationship between two items which include all of the following: strength of association, consistency, temporality, biological gradient, plausibility, coherence, experimental evidence and analogy.

RESULTS

The hypothesis that AN and BN have a single cause did not meet all of Hill's Criteria of Causation. Strength of association, plausibility, analogy and some experimental evidence were met, but not consistency, specificity, temporality, biological gradient, coherence and most experimental evidence.

CONCLUSIONS

The hypothesis that AN and BN are a single disorder with a common cause is not supported by Hill's Criteria of Causation. This argues against the notion of a transdiagnostic theory of eating disorders.

A cross-sectional and follow-up voxel-based morphometric MRI study in adolescent anorexia nervosa

The objective was to examine whether cerebral volumes are reduced, and in what regions, in adolescents with anorexia nervosa and to study changes after nutritional recovery. Twelve anorexia nervosa (DSM-IV) patients aged 11-17 consecutively admitted to an Eating Disorders Unit were assessed by means of psychopathological scales, neuropsychological battery and voxel-based morphometric (VBM) magnetic resonance imaging at admission and after 7 months' follow-up. Nine control subjects of similar age, gender and estimated intelligence level were also studied. The two groups showed differences in gray matter (F=22.2; p<0.001) and cerebrospinal fluid (CSF) (F=21.2; p<0.001) but not in white matter volumes. In anorexic patients, gray matter volume correlated negatively with the copy time from the Rey Complex Figure Test. In the regional VBM study several temporal and parietal gray matter regions were reduced. During follow-up there was a greater global increase in gray matter (F=10.7; p=0.004) and decrease in CSF (F=22.1; p=0.001) in anorexic patients. The increase in gray matter correlated with a decrease in cortisol (Spearman correlation=-0.73; p=0.017). At follow-up there were no differences in global gray matter (F=2.1; p=0.165), white matter (F=0.02, p=0.965) or CSF (F=1.8; p=0.113) volumes between both groups. There were still some smaller areas, in the right temporal and both supplementary motor area, showing differences between them in the regional VBM study. In conclusion, in adolescent anorexic patients gray matter is more affected than white matter and mainly involves the posterior regions of the brain. Overall gray matter alterations are reversible after nutritional recovery.

Neuroimaging in eating disorders and obesity: implications for research

Medicine and psychiatry have benefited from developments in investigational techniques. Neuroimaging is one such domain that has technically progressed enormously in recent years, resulting in, for example, higher temporal and spatial resolution. Neuroimaging techniques have been widely used in a range of psychiatric disorders, providing new insights into neural brain circuits and neuroreceptor functions in vivo. These imaging techniques allow researchers to study not only the configuration of brain structures but also aspects of normal and anomalous human behavior more accurately.

What potential role is there for medication treatment in anorexia nervosa?

OBJECTIVE

To review selected issues regarding the development of drug treatments for anorexia nervosa (AN).

METHOD

The existing pharmacotherapy literature for AN is reviewed, and the theoretical and practical considerations are discussed.

RESULTS

A very wide variety of drugs have been examined in AN, generally with negative results. There are a number of potential reasons for this finding, including compliance, nutritional deficits, selection of the wrong targets or the wrong outcome measures, use of monotherapy, lack of animal models, or factors intrinsic to AN.

CONCLUSION

Pharmacotherapy provides little benefit in the treatment of AN at present. Several strategies might lead to the identification of more effective agents, including new measurement strategies, identification of novel pharmacologic targets, and consideration of a clinical trials network.

Starving neurons show sex difference in autophagy

Sex-dependent differences in adaptation to famine have long been appreciated, thought to hinge on female versus male preferences for fat versus protein sources, respectively. However, whether these differences can be reduced to neurons, independent of typical nutrient depots, such as adipose tissue, skeletal muscle, and liver, was heretofore unknown. A vital adaptation to starvation is autophagy, a mechanism for recycling amino acids from organelles and proteins. Here we show that segregated neurons from males in culture are more vulnerable to starvation than neurons from females. Nutrient deprivation decreased mitochondrial respiration, increased autophagosome formation, and produced cell death more profoundly in neurons from males versus females. Starvation-induced neuronal death was attenuated by 3-methyladenine, an inhibitor of autophagy; Atg7 knockdown using small interfering RNA; or L-carnitine, essential for transport of fatty acids into mitochondria, all more effective in neurons from males versus females. Relative tolerance to nutrient deprivation in neurons from females was associated with a marked increase in triglyceride and free fatty acid content and a cytosolic phospholipase A2-dependent increase in formation of lipid droplets. Similar sex differences in sensitivity to nutrient deprivation were seen in fibroblasts. However, although inhibition of autophagy using Atg7 small interfering RNA inhibited cell death during starvation in neurons, it increased cell death in fibroblasts, implying that the role of autophagy during starvation is both sex- and tissue-dependent. Thus, during starvation, neurons from males more readily undergo autophagy and die, whereas neurons from females mobilize fatty acids, accumulate triglycerides, form lipid droplets, and survive longer.

Cognitive function and brain structure in females with a history of adolescent-onset anorexia nervosa

OBJECTIVE

Abnormalities in cognitive function and brain structure have been reported in acutely ill adolescents with anorexia nervosa, but whether these abnormalities persist or are reversible in the context of weight restoration remains unclear. Brain structure and cognitive function in female subjects with adolescent-onset anorexia nervosa assessed at long-term follow-up were studied in comparison with healthy female subjects, and associations with clinical outcome were investigated.

PATIENTS AND METHODS

Sixty-six female subjects (aged 21.3 +/- 2.3 years) who had a diagnosis of adolescent-onset anorexia nervosa and treated 6.5 +/- 1.7 years earlier in a tertiary care hospital and 42 healthy female control subjects (aged 20.7 +/- 2.5 years) were assessed. All participants underwent a clinical examination, magnetic resonance brain scan, and cognitive evaluation. Clinical data were analyzed first as a function of weight recovery (n = 14, <85% ideal body weight; n = 52, >or=85% ideal body weight) and as a function of menstrual status (n = 18, absent/irregular menses; n = 29, oral contraceptive pill; n = 19, regular menses). Group comparisons were made across structural brain volumes and cognitive scores.

RESULTS

Compared with control subjects, participants with anorexia nervosa who remained at low weight had larger lateral ventricles. Twenty-four-hour urinary free-cortisol levels were positively correlated with volumes of the temporal horns of the lateral ventricles and negatively correlated with volumes of the hippocampi in clinical participants. Participants who were amenorrheic or had irregular menses showed significant cognitive deficits across a broad range of many domains.

CONCLUSIONS

Female subjects with adolescent-onset anorexia nervosa showed abnormal cognitive function and brain structure compared with healthy individuals despite an extended period since diagnosis. To our knowledge, this is the first study to report a specific relationship between menstrual function and cognitive function in this patient population. Possible mechanisms underlying neural and cognitive deficits with anorexia nervosa are discussed. Additional examination of the effects of estrogen on cognitive function in female subjects with anorexia nervosa is necessary.

Conserved and differential effects of dietary energy intake on the hippocampal transcriptomes of females and males

The level of dietary energy intake influences metabolism, reproductive function, the development of age-related diseases, and even cognitive behavior. Because males and females typically play different roles in the acquisition and allocation of energy resources, we reasoned that dietary energy intake might differentially affect the brains of males and females at the molecular level. To test this hypothesis, we performed a gene array analysis of the hippocampus in male and female rats that had been maintained for 6 months on either ad libitum (control), 20% caloric restriction (CR), 40% CR, intermittent fasting (IF) or high fat/high glucose (HFG) diets. These diets resulted in expected changes in body weight, and circulating levels of glucose, insulin and leptin. However, the CR diets significantly increased the size of the hippocampus of females, but not males. Multiple genes were regulated coherently in response to energy restriction diets in females, but not in males. Functional physiological pathway analyses showed that the 20% CR diet down-regulated genes involved in glycolysis and mitochondrial ATP production in males, whereas these metabolic pathways were up-regulated in females. The 40% CR diet up-regulated genes involved in glycolysis, protein deacetylation, PGC-1α and mTor pathways in both sexes. IF down-regulated many genes in males including those involved in protein degradation and apoptosis, but up-regulated many genes in females including those involved in cellular energy metabolism, cell cycle regulation and protein deacetylation. Genes involved in energy metabolism, oxidative stress responses and cell death were affected by the HFG diet in both males and females. The gender-specific molecular genetic responses of hippocampal cells to variations in dietary energy intake identified in this study may mediate differential behavioral responses of males and females to differences in energy availability.

The effects of stress on body weight: biological and psychological predictors of change in BMI

OBJECTIVE

To investigate individual differences in the effects of stress on BMI.

RESEARCH METHODS AND PROCEDURES

Participants were 71 healthy women volunteers enrolled in a university-based nurse practitioner program. Predictors of change in BMI were hypothesized to be cortisol secretion, dietary restraint, binging, mastery, mood, and eating attitudes. Measures were made at the beginning of the academic semester and 12 weeks later during the participants' examination period.

RESULTS

The women were of normal weight (BMI 25.2 +/- 4.3) for their age [43; standard deviation (SD), 7]. By the examination period, 40 had gained weight (mean, 5.5 pounds; SD, 2.2), 19 lost weight (mean, 2.5 pounds; SD, 1.5), and 12 had stable weight. BMI, salivary cortisol secretion, binging behavior, depression, and anxiety increased significantly, whereas scores on dietary restraint, weight, shape, and eating concerns, and mastery decreased significantly. Regression analysis showed that change in daily cortisol secretion significantly predicted change in BMI and that mastery significantly moderated this relationship. However, a reduction in dietary restraint was a perfect mediator of this relationship. Change in cortisol secretion also significantly predicted change in dietary restraint, and this was moderated by dietary restraint at the beginning of the academic semester. Reduction in dietary restraint was also predicted by a reduction in mastery and weight concern.

DISCUSSION

We identified individual differences that confer vulnerability to weight gain during stressful life events (dietary restraint and mastery). Given that women are exposed to daily stressors and use cognitive strategies to restrain their dietary intake, increasing awareness of the role of stress on eating behavior and weight is an important goal.

Sex-dependent metabolic, neuroendocrine, and cognitive responses to dietary energy restriction and excess

Females and males typically play different roles in survival of the species and would be expected to respond differently to food scarcity or excess. To elucidate the physiological basis of sex differences in responses to energy intake, we maintained groups of male and female rats for 6 months on diets with usual, reduced [20% and 40% caloric restriction (CR), and intermittent fasting (IF)], or elevated (high-fat/high-glucose) energy levels and measured multiple physiological variables related to reproduction, energy metabolism, and behavior. In response to 40% CR, females became emaciated, ceased cycling, underwent endocrine masculinization, exhibited a heightened stress response, increased their spontaneous activity, improved their learning and memory, and maintained elevated levels of circulating brain-derived neurotrophic factor. In contrast, males on 40% CR maintained a higher body weight than the 40% CR females and did not change their activity levels as significantly as the 40% CR females. Additionally, there was no significant change in the cognitive ability of the males on the 40% CR diet. Males and females exhibited similar responses of circulating lipids (cholesterols/triglycerides) and energy-regulating hormones (insulin, leptin, adiponectin, ghrelin) to energy restriction, with the changes being quantitatively greater in males. The high-fat/high-glucose diet had no significant effects on most variables measured but adversely affected the reproductive cycle in females. Heightened cognition and motor activity, combined with reproductive shutdown, in females may maximize the probability of their survival during periods of energy scarcity and may be an evolutionary basis for the vulnerability of women to anorexia nervosa.

Neuropsychologische Beeinträchtigungen und kognitive Verarbeitung von Essensreizen bei Anorexia nervosa

Zusammenfassung. Essstörungen stellen eine wichtige psychiatrische Behandlungsindikation dar. Es ist bekannt, dass bei diesen Erkrankungen auch klinisch relevante kognitive Defizite und Auffälligkeiten in der Informationsverarbeitung bestehen, die im Alltag der PatientInnen zu Beeinträchtigungen führen. Insbesondere im Hinblick auf die schwierige und langwierige Behandlung und hohen Rückfallquoten dieser Patientengruppe ist die Berücksichtigung dieser kognitiven Besonderheiten in der Therapie von Essstörungen wichtig. Der vorliegende Artikel beschreibt neurokognitive Auffälligkeiten bei Anorexia nervosa (AN) in verschiedenen relevanten Funktionsbereichen. Im zweiten Teil der Arbeit werden aktuelle Verhaltens- und Bildgebungsstudien zur Verarbeitung von nahrungsrelevanten Stimuli dargestellt.