Comparison of regional cerebral blood flow in patients with anorexia nervosa before and after weight gain

Myo-inositol Levels in the Dorsal Anterior Cingulate Cortex Predicts Anxiety-to-Eat in Anorexia Nervosa

Background

Anorexia nervosa (AN) is a mental and behavioral health condition characterized by an intense fear of weight or fat gain, severe restriction of food intake resulting in low body weight, and distorted self-perception of body shape or weight. While substantial research has focused on general anxiety in AN, less is known about eating-related anxiety and its underlying neural mechanisms. Therefore, we sought to characterize anxiety-to-eat in AN and examine the neurometabolic profile within the dorsal anterior cingulate cortex (dACC), a brain region putatively involved in magnifying the threat response.

Methods

Women seeking inpatient treatment for AN and women of healthy weight without a lifetime history of an eating disorder (healthy controls; HC) completed a computer-based behavioral task assessing anxiety-to-eat in response to images of higher (HED) and lower (LED) energy density foods. Participants also underwent magnetic resonance spectroscopy of the dACC in a 3 Tesla scanner.

Results

The AN group reported greater anxiety to eat HED and LED foods relative to the HC group. Both groups reported greater anxiety to eat HED foods relative to LED foods. The neurometabolite myo-inositol (mI) was lower in the dACC in AN relative to HC, and mI levels negatively predicted anxiety to eat HED but not LED foods in the AN group only. mI levels in the dACC were independent of body weight, body mass, and general anxiety.

Conclusions

These findings provide critical new insight into the clinically challenging feature and underlying neural mechanisms of eating-related anxiety and indicate mI levels in the dACC could serve as a novel biomarker of illness severity that is independent of body weight to identify individuals vulnerable to disordered eating or eating pathology as well as a potential therapeutic target.

Originalbeiträge (Originals). Altered microvascular density in patients with anorexia nervosa – an optical coherence tomography angiography (OCTA) pilot study

OBJECTIVES

To investigate macular and peripapillary vascular density (VD) in patients with anorexia nervosa (AN) compared to healthy controls. Methods:Whole face scans of the superficial and deep macular layers and whole face and peripapillary scans of the radial peripapillary capillaries (RPC) were obtained using optical coherence tomography angiography (OCTA, AngioVueR, Optovue) in ten patients with AN and ten age-matched controls.The primary objective was to determine whether there was a difference between the vessel density (VD) in the above areas in AN and controls. P-values ≤ 0.0125 were considered statistically significant. Results: VD in the superficialmacular en-face OCTA image was significantly lower in the study group compared to the control group. Neither the deepmacula nor the radial peripapillary capillary (RPC) in the whole-face image nor the RPC-peripapillary imaging appeared to be significantly different. Conclusion: Patients with AN showed reduced VD in the superficialmacular layers compared to healthy controls, which can be discussed as a consequence of the malnutrition. OCTA could be a useful non- invasive tool to detect reduced peripheral blood supply to show vascular changes that occur before ocular symptoms.

The Effect of Transcranial Direct Current Stimulation (tDCS) on Anorexia Nervosa: A Narrative Review

(1) Introduction: Anorexia nervosa (AN) is a severe, debilitating disease with high incidence and high mortality. The methods of treatment used so far are moderately effective. Evidence from neuroimaging studies helps to design modern methods of therapy. One of them is transcranial direct current stimulation (tDCS), a non-invasive brain neuromodulation technique. (2) Methods: The purpose of this narrative review is to bring together all studies investigating the use of tDCS in the treatment of AN and to evaluate its effect and efficiency. Searches were conducted in the Pubmed/Medline, Research Gate, and Cochrane databases. (3) Results: The literature search resulted in five articles. These studies provide preliminary evidence that tDCS has the potential to alter eating behaviour, body weight, and food intake. Additionally, tDCS reduced symptoms of depression. Throughout all trials, stimulation targeted the left dorsolateral prefrontal cortex (DLPFC). Although the number of studies included is limited, attempts were made to elucidate the potential mechanisms underlying tDCS action in individuals with AN. Recommendations for future tDCS research in AN were issued. (4) Conclusions: The included studies have shown that tDCS stimulation of the left DLPFC has a positive effect on AN clinical symptoms and may improve them, as measured by various assessment measures. It is important to conduct more in-depth research on the potential benefits of using tDCS for treating AN. This should entail well-designed studies incorporating advanced neuroimaging techniques, such as fMRI. The aim is to gain a better understanding of how tDCS works in AN.

Protective Effects of 4-Trifluoromethyl-(E)-cinnamoyl]-L-4-F-phenylalanine Acid against Chronic Cerebral Hypoperfusion Injury through Promoting Brain-Derived Neurotrophic Factor-Mediated Neurogenesis

Vascular dementia (VaD), one of the major consequences after stroke, is the second reason for the cognitive decline in aged people. Chronic cerebral hypoperfusion (CCH) is considered as the main cause for cognitive impairment in VaD patients. In our previous study, a synthetic compound, 4-trifluoromethyl-(E)-cinnamoyl]-L-4-F-phenylalanine acid (AE-18), has been proven to decrease infarct volume and to recover the insufficient blood supply after ischemia-reperfusion in rats, which was reminded that AE-18 may possess the ameliorative effect in CCH. In this study, the bilateral common carotid artery occlusion was performed to establish the CCH model in rats to evaluate the effect and mechanisms of AE-18 in CCH. Results showed that AE-18 (5 and 10 mg/kg, i.g.) could recover the learning and memory and increase the number of neurons in the hippocampus, which may be attributed to its neurogenesis effects and its recovery of cerebral blood flow in CCH rats. In addition, the in vitro studies showed that AE-18 promoted neuronal proliferation, induced differentiation of Neuro-2a cells into a neuron-like morphology, and accelerated the establishment of axon-dendrite polarization of primary hippocampal neurons through upregulating brain-derived neurotrophic factor via the PI3K/Akt/CREB pathway. In conclusion, AE-18 is a promising candidate for the treatment of cognitive decline after CCH injury by restoring blood supply to the brain and promoting neurogenesis in the hippocampus.

Structural and functional brain alterations in anorexia nervosa:A multimodal meta-analysis of neuroimaging studies

Anorexia nervosa (AN) is a complex psychiatric disorder with poorly understood etiology. Numerous voxel‐based morphometry (VBM) and resting‐state functional imaging studies have provided strong evidence of abnormal brain structure and intrinsic and functional activities in AN, but with inconsistent conclusions. Herein, a whole‐brain meta‐analysis was conducted on VBM (660 patients with AN, and 740 controls) and resting‐state functional imaging (425 patients with AN, and 461 controls) studies that measured differences in the gray matter volume (GMV) and intrinsic functional activity between patients with AN and healthy controls (HCs). Overall, patients with AN displayed decreased GMV in the bilateral median cingulate cortex (extending to the bilateral anterior and posterior cingulate cortex), and left middle occipital gyrus (extending to the left inferior parietal lobe). In resting‐state functional imaging studies, patients with AN displayed decreased resting‐state functional activity in the bilateral anterior cingulate cortex and bilateral median cingulate cortex, and increased resting‐state functional activity in the right parahippocampal gyrus. This multimodal meta‐analysis identified reductions of gray matter and functional activity in the anterior and median cingulate in patients with AN, which contributes to further understanding of the pathophysiology of AN.

A pilot study exploring the effect of repetitive transcranial magnetic stimulation (rTMS) treatment on cerebral blood flow and its relation to clinical outcomes in severe enduring anorexia nervosa

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a novel treatment option for people with severe enduring anorexia nervosa (SE-AN), but associated neurobiological changes are poorly understood. This study investigated the effect of rTMS treatment on regional cerebral blood flow (CBF) and whether any observed changes in CBF are associated with changes in clinical outcomes in people with SE-AN.

METHODS

As part of a randomised sham-controlled feasibility trial of 20 sessions of high-frequency rTMS to the left dorsolateral prefrontal cortex, 26 of 34 trial participants completed arterial spin labelling (ASL) functional magnetic resonance imaging (fMRI) to quantify regional and global resting state CBF before (pre-randomisation baseline) and after real or sham treatment (1-month post-randomisation). A group of healthy females (n = 30) were recruited for baseline comparison. Clinical outcomes, including BMI, and depression and anxiety symptoms, were assessed at baseline, 1-, 4-, and 18-months post-randomisation.

RESULTS

No group differences in regional CBF were identified between the SE-AN and healthy comparison participants. A significant treatment-by-time interaction in a medial temporal lobe cluster with the maximal peak in the right amygdala was identified, reflecting a greater reduction in amygdala CBF following real rTMS compared to sham. Participants with the greatest rTMS-related reduction in amygdala CBF (i.e., between baseline and 1-month post-randomisation) showed the greatest sustained weight gain at 18-months post-randomisation. Higher baseline CBF in the insula predicted greater weight gain between baseline and 1-month post-randomisation and between baseline and 4-months post-randomisation.

CONCLUSIONS

This exploratory pilot study identified rTMS treatment related changes in CBF in adults with SE-AN and these were associated with changes in weight. Our preliminary findings also suggest that CBF (as measured by ASL fMRI) may be a marker of rTMS treatment response in this patient group. Future rTMS studies in AN should employ longitudinal neuroimaging to further explore the neurobiological changes related to rTMS treatment.

TRIAL REGISTRATION

ISRCTN14329415 , registered 23rd July 2015.

The effect of a single yoga class on interoceptive accuracy in patients affected by anorexia nervosa and in healthy controls: a pilot study

PURPOSE

To evaluate interoceptive accuracy (Iac) before and after a single yoga class in a population of patients with anorexia nervosa (AN) and in a population of healthy controls (HC).

METHODS

Fifteen patients with AN and twenty HC were included in the study. All individuals participated in a single yoga class. Before (T0) and after (T1) the yoga class, they underwent the heartbeat detection task for the evaluation of Iac. At T0, all participants also underwent a psychological assessment, including evaluation of depression, anxiety, body awareness, alexithymia, self-objectification and eating disorders psychopathology.

RESULTS

Patients with AN had lower Iac than HC at T0. A significant improvement of Iac at T1 was found in the HC group but not in the group of patients with AN.

CONCLUSION

We infer that our findings might be linked to the fact that patients with AN, differently from HC, did not properly attend to their bodies, despite the yoga class. This hypothesis is consistent with previous studies showing that patients with AN have decreased Iac during self-focused behavior because of body-related avoidance. Moreover, we surmise that HC might be keener to improve their perception of internal body signals even after a single yoga class because their emotional awareness system is not impaired. Patients with AN, on the contrary, may have an intrinsic impairment of their emotional awareness, making it harder for them to modulate their Iac.

LEVEL OF EVIDENCE

Level III, evidence obtained from well-designed cohort or case-control analytical studies.

Neuroimaging Findings in Adolescents and Young Adults with Anorexia Nervosa: A Systematic Review

BACKGROUND

Anorexia nervosa (AN) is a serious, multifactorial mental disorder affecting predominantly young females. This systematic review examines neuroimaging findings in adolescents and young adults up to 24 years old, in order to explore alterations associated with disease pathophysiology.

METHODS

Eligible studies on structural and functional brain neuroimaging were sought systematically in PubMed, CENTRAL and EMBASE databases up to 5 October 2020.

RESULTS

Thirty-three studies were included, investigating a total of 587 patients with a current diagnosis of AN and 663 healthy controls (HC). Global and regional grey matter (GM) volume reduction as well as white matter (WM) microstructure alterations were detected. The mainly affected regions were the prefrontal, parietal and temporal cortex, hippocampus, amygdala, insula, thalamus and cerebellum as well as various WM tracts such as corona radiata and superior longitudinal fasciculus (SLF). Regarding functional imaging, alterations were pointed out in large-scale brain networks, such as default mode network (DMN), executive control network (ECN) and salience network (SN). Most findings appear to reverse after weight restoration. Specific limitations of neuroimaging studies in still developing individuals are also discussed.

CONCLUSIONS

Structural and functional alterations are present in the early course of the disease, most of them being partially or totally reversible. Nonetheless, neuroimaging findings have been open to many biological interpretations. Thus, more studies are needed to clarify their clinical significance.

Multimodal neuroimaging in anorexia nervosa

Anorexia nervosa (AN) is a severe and complex psychiatric disorder characterized by intense fear about weight gain and finalized to food-related control behaviors. Growing interest has been demonstrated about neurobiological processes subtend to AN physiopathology. The present review aimed to collect neurostructural and neurofunctional available data from 2010 to 2019. Results have been organized according to the neuroimaging technique employed, also including a specific section on electroencephalographic results, mostly neglected in previous reviews. Diffuse cerebral vulnerability has been demonstrated and the contribution of several structures has been identified. Insula, cingulate cortex, parietal and frontal areas are primarily involved both by structural and functional perspectives. Moreover, consistent alterations in white matter integrity and brain electrical activity have been reported. Neuroimaging findings give a substantial contribution to AN pathophysiological description, also in order to understand altered but reversible processes in the passage from acute illness phase to disorder's remission, useful also for defining therapy.

Functional neuroimaging in anorexia nervosa: A clinical approach

Aims

To provide a review of the available literature about the functional neuroimaging of anorexia nervosa, and to summarize the possible role of neurobiological factors in its pathogenesis.

Methods

A systematic review of the literature was performed using PubMed and Medline electronic database (1950–September 2009). Eligible studies were restricted to those involving the main parameters of cerebral activity and functional neuroimaging techniques. Findings of the reviewed studies have been grouped on a diagnostic subtype basis, and their comparison has been interpreted in terms of concordance.

Results

We found a high level of concordance among available studies with regard to the presence of frontal, parietal and cingulate functional disturbances in both anorexia nervosa restricting and binge/purging subtypes. Concordance among studies conducted regardless of the anorexia nervosa subtypes suggests an alteration in temporal and parietal functions and striatal metabolism.

Conclusions

The most consistent alterations in anorexia nervosa cerebral activity seem to involve the dorsolateral prefrontal cortex, the inferior parietal lobule, the anterior cingulate cortex and the caudate nucleus. They may affect different neural systems such as the frontal visual system, the attention network, the arousal and emotional processing systems, the reward processing network, and the network for the body schema.

The effect of the demyelinating agent cuprizone on binge-like eating of sweetened palatable food in female and male C57BL/6 substrains

Binge eating is a heritable symptom of eating disorders with an unknown genetic etiology. Rodent models for binge-like eating (BLE) of palatable food permit the study of genetic and biological mechanisms. We previously genetically mapped a coding mutation in Cyfip2 associated with increased BLE of sweetened palatable food in the C57BL/6NJ versus C57BL/6J substrain. The increase in BLE in C57BL/6NJ mice was associated with a decrease in transcription of genes enriched for myelination in the striatum. Here, we tested the hypothesis that decreasing myelin levels with the demyelinating agent cuprizone would enhance BLE. Mice were treated with a 0.3% cuprizone home cage diet for two weeks. Cuprizone induced similar weight loss in both substrains and sexes that recovered within 48 h after removal of cuprizone. Following a three-week recovery period, mice were trained for BLE in an intermittent, limited access procedure. Surprisingly, cuprizone significantly reduced BLE in male but not female C57BL/6NJ mice while having no effect in C57BL/6J mice. Cuprizone also reduced myelin basic protein (MBP) at seven weeks post-cuprizone removal while having no effect on myelin-associated glycoprotein at this time point. C57BL/6NJ mice also showed less MBP than C57BL/6J mice. There were no statistical interactions of Treatment with Sex on MBP levels, indicating that differences in MBP reduction are unlikely to account for sex differences in BLE. To summarize, cuprizone induced an unexpected, significant reduction in BLE in C57BL/6NJ males, which could indicate genotype-dependent sex differences in the biological mechanisms of BLE.

Basal ganglia volume and shape in anorexia nervosa

Background

Reward-centred models have proposed that anomalies in the basal ganglia circuitry that underlies reward learning and habit formation perpetuate anorexia nervosa (AN). The present study aimed to investigate the volume and shape of key basal ganglia regions, including the bilateral caudate, putamen, nucleus accumbens (NAcc), and globus pallidus in AN.

Methods

The present study combined data from two existing studies resulting in a sample size of 46 women with AN and 56 age-matched healthy comparison (HC) women. Group differences in volume and shape of the regions of interest were examined. Within the AN group, the impact of eating disorder characteristics on volume and shape of the basal ganglia regions were also explored.

Results

The shape analyses revealed inward deformations in the left caudate, right NAcc, and bilateral ventral and internus globus pallidus, and outward deformations in the right middle and posterior globus pallidus in the AN group.

Conclusions

The present findings appear to fit with the theoretical models suggesting that there are alterations in the basal ganglia regions associated with habit formation and reward processing in AN. Further investigation of structural and functional connectivity of these regions in AN as well as their role in recovery would be of interest.

Neuroendocrinology of reward in anorexia nervosa and bulimia nervosa: Beyond leptin and ghrelin

The pathophysiology of anorexia nervosa (AN) and bulimia nervosa (BN) are still poorly understood, but psychobiological models have proposed a key role for disturbances in the neuroendocrines that signal hunger and satiety and maintain energy homeostasis. Mounting evidence suggests that many neuroendocrines involved in the regulation of homeostasis and body weight also play integral roles in food reward valuation and learning via their interactions with the mesolimbic dopamine system. Neuroimaging data have associated altered brain reward responses in this system with the dietary restriction and binge eating and purging characteristic of AN and BN. Thus, neuroendocrine dysfunction may contribute to or perpetuate eating disorder symptoms via effects on reward circuitry. This narrative review focuses on reward-related neuroendocrines that are altered in eating disorder populations, including peptide YY, insulin, stress and gonadal hormones, and orexins. We provide an overview of the animal and human literature implicating these neuroendocrines in dopaminergic reward processes and discuss their potential relevance to eating disorder symptomatology and treatment.

Functional MRI with a set-shifting task in adolescent anorexia nervosa: A cross-sectional and follow-up study

Studies of set-shifting in adolescent AN present conflicting results, since not all have found differences with regard to controls. To date, no functional Magnetic Resonance Imaging (fMRI) studies have been carried out in adolescent patients, nor have patients been assessed after weight recovery. In this study, 30 female AN patients aged 12-17 and 16 matched control subjects were assessed both at baseline and after six months and renutrition using a structured diagnostic interview, clinical and neurocognitive scales, and fMRI during a set-shifting task. Adolescent AN patients presented similar performance on different neurocognitive tests and also on a set-shifting task during fMRI, but they showed a lower activation in the inferior and middle occipital and lingual gyri, fusiform gyri and cerebellum during the set-shifting task. No correlations were found between decreased activation and clinical variables such as body mass index, eating or depressive symptoms. After six months of treatment and renutrition in AN patients, there were no differences between patients and controls. These results show that adolescent AN patients have lower activation in relevant brain areas during a set-shifting task, and support the use of fMRI with set-shifting paradigms as a biomarker in future studies.

The potential of calibrated fMRI in the understanding of stress in eating disorders

Eating disorders (ED), including Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Binge Eating Disorder (BED), are medically dangerous psychiatric disorders of unknown etiology. Accumulating evidence supports a biopsychosocial model that includes genetic heritability, neurobiological vulnerability, and psychosocial factors, such as stress, in the development and maintenance of ED. Notably, stress hormones influence appetite and eating, and dysfunction of the physiological stress response has been implicated in ED pathophysiology. Stress signals also appear associated with food reward neurocircuitry response in ED, providing a possible mechanism for the role of stress in appetite dysregulation. This paper provides a review of some of the interacting psychological, behavioral, physiological, and neurobiological mechanisms involved in the stress response among individuals with ED, and discusses novel neuroimaging techniques to address potential physiological confounds of studying neural correlates of stress in ED, such as calibrated fMRI.

Women with Anorexia Nervosa do not show altered tactile localization compared to healthy controls

Body image disturbance is a key symptom of Anorexia Nervosa (AN). Previous studies found that women with AN overestimate their body size in comparison with healthy controls (HC), at least for unimodal measures involving either only visual input (e.g. distorted photographs technique) or only tactile input (e.g. tactile distance tasks). Distorted body representations are hypothesized to cause this misperception in AN. We here tested whether this overestimation remains present in a novel one-point-localization (OPL) task involving the mapping of a tactile stimulus onto a visual image. Two experiments compared the ability of 27 women with AN and 40 HC to accurately localize a tactile stimulus on a live image of their body. Women with AN and HC did not differ in their performance. Instead, participants in both groups showed systematic distortions in their localization performance. This study suggests that the mapping of a tactile stimulus does not involve a distorted body representation in women with AN compared to HC.

Altered Medial Frontal Feedback Learning Signals in Anorexia Nervosa

BACKGROUND

In their relentless pursuit of thinness, individuals with anorexia nervosa (AN) engage in maladaptive behaviors (restrictive food choices and overexercising) that may originate in altered decision making and learning.

METHODS

In this functional magnetic resonance imaging study, we employed computational modeling to elucidate the neural correlates of feedback learning and value-based decision making in 36 female patients with AN and 36 age-matched healthy volunteers (12-24 years). Participants performed a decision task that required adaptation to changing reward contingencies. Data were analyzed within a hierarchical Gaussian filter model that captures interindividual variability in learning under uncertainty.

RESULTS

Behaviorally, patients displayed an increased learning rate specifically after punishments. At the neural level, hemodynamic correlates for the learning rate, expected value, and prediction error did not differ between the groups. However, activity in the posterior medial frontal cortex was elevated in AN following punishment.

CONCLUSIONS

Our findings suggest that the neural underpinning of feedback learning is selectively altered for punishment in AN.

Aberrant Cerebral Blood Flow in Response to Hunger and Satiety in Women Remitted from Anorexia Nervosa

The etiology of pathological eating in anorexia nervosa (AN) remains poorly understood. Cerebral blood flow (CBF) is an indirect marker of neuronal function. In healthy adults, fasting increases CBF, reflecting increased delivery of oxygen and glucose to support brain metabolism. This study investigated whether women remitted from restricting-type AN (RAN) have altered CBF in response to hunger that may indicate homeostatic dysregulation contributing to their ability to restrict food. We compared resting CBF measured with pulsed arterial spin labeling in 21 RAN and 16 healthy comparison women (CW) when hungry (after a 16-h fast) and after a meal. Only remitted subjects were examined to avoid the confounding effects of malnutrition on brain function. Compared to CW, RAN demonstrated a reduced difference in the Hungry − Fed CBF contrast in the right ventral striatum, right subgenual anterior cingulate cortex (p_corr < 0.05) and left posterior insula (p_unc < 0.05); RAN had decreased CBF when hungry versus fed, whereas CW had increased CBF when hungry versus fed. Moreover, decreased CBF when hungry in the left insula was associated with greater hunger ratings on the fasted day for RAN. This represents the first study to show that women remitted from AN have aberrant resting neurovascular function in homeostatic neural circuitry in response to hunger. Regions involved in homeostatic regulation showed group differences in the Hungry − Fed contrast, suggesting altered cellular energy metabolism in this circuitry that may reduce motivation to eat.

Reduced Resting-State Functional Connectivity in Current and Recovered Restrictive Anorexia Nervosa

Functional connectivity studies based on resting-state functional magnetic resonance imaging (rs-fMRI) have shown alterations in brain networks associated with self-referential processing, cognitive control, and somatosensory processing in anorexia nervosa (AN). This study aimed to further investigate the functional connectivity of resting-state networks (RSNs) in homogenous subsamples of individuals with restrictive AN (current and recovered) and the relationship this has with core eating disorder psychopathology. rs-fMRI scans were obtained from 12 female individuals with restrictive AN, 14 females recovered from restrictive AN, and 16 female healthy controls. Independent components analysis revealed a set of functionally relevant RSNs, previously reported in the literature. Dual regression analysis showed decreased temporal coherence within the lateral visual and auditory RSNs in individuals with current AN and those recovered from AN compared to healthy individuals. This decreased connectivity was also found in regions associated with somatosensory processing, and is consistent with reduced interoceptive awareness and body image perception, characteristic of AN. Widespread gray matter (GM) reductions were also found in both the AN groups, and differences in functional connectivity were no longer significant when GM maps were added as a covariate in the dual regression analysis. This raises the possibility that deficits in somatosensory and interoceptive processing observed in AN may be in part underpinned or exacerbated by GM reductions.

Voxel-based morphometry reveals brain gray matter volume changes in successful dieters

OBJECTIVE

To compare regional brain volume predictors of percent weight loss (WL) in dieters with obesity (DwO) and in the same participants categorized as "successful" (≥7% WL) or "unsuccessful" dieters (<7% WL).

METHODS

DwO (n = 72) and participants with healthy weight (n = 22) completed a structural MRI at baseline and 3 months. All DwO participants were enrolled in a 12-week program consisting of a reduced calorie diet, increased physical activity, and behavioral modification. SPM8-based voxel-based morphometry processing streams were used for measurements of regional gray (GMV) and white matter volume and longitudinal changes in volume. Correlations between WL and baseline brain volume and change in brain volume, as well as differences between groups, were then tested.

RESULTS

%WL was positively correlated with baseline GMV in right parahippocampal and orbitofrontal gyri in DwO. Successful dieters showed greater GMV loss in the left precentral gyrus and the insula compared with unsuccessful dieters. A negative correlation was found between %WL and GMV change from baseline in the left prefrontal regions.

CONCLUSIONS

Findings illustrate that WL is related to volumetric changes in brain areas previously linked to interoception and food motivation.

Cerebro- and Cardio-vascular Responses to Energy Drink in Young Adults: Is there a Gender Effect?

Background and Purpose: Energy drinks (EDs) are suspected to induce potential adverse cardiovascular effects and have recently been shown to reduce cerebral blood flow velocity (CBFV) in young, healthy subjects. Gender differences in CBFV in response to EDs have not previously been investigated, despite the fact that women are more prone to cardiovascular disturbances such as neurocardiogenic syncope than men. Therefore, the aim of this study was to explore gender differences in cerebrovascular and cardiovascular responses to EDs.

Methods: We included 45 subjects in a retrospective analysis of pooled data from two previous randomized trials carried out in our laboratory with similar protocols. Beat-to-beat blood pressure, impedance cardiography, transcranial Doppler, and end-tidal carbon dioxide (etCO₂) measurements were made for at least 20 min baseline and for 80 min following the ingestion of 355 mL of a sugar-sweetened ED. Gender and time differences in cerebrovascular and cardiovascular parameters were investigated.

Results: CBFV was significantly reduced in response to ED, with the greatest reduction observed in women compared with men (−12.3 ± 0.8 vs. −9.7 ± 0.8%, P < 0.05). Analysis of variance indicated significant time (P < 0.01) and gender × time (P < 0.01) effects. The percentage change in CBFV in response to ED was independent of body weight and etCO₂. No significant gender difference in major cardiovascular parameters in response to ED was observed.

Conclusions: ED ingestion reduced CBFV over time, with a greater reduction observed in women compared with men. Our results have potential implications for women ED consumers, as well as high-risk individuals.

Cerebellar sub-divisions differ in exercise-induced plasticity of noradrenergic axons and in their association with resilience to activity-based anorexia

The vermis or "spinocerebellum" receives input from the spinal cord and motor cortex for controlling balance and locomotion, while the longitudinal hemisphere region or "cerebro-cerebellum" is interconnected with non-motor cortical regions, including the prefrontal cortex that underlies decision-making. Noradrenaline release in the cerebellum is known to be important for motor plasticity but less is known about plasticity of the cerebellar noradrenergic (NA) system, itself. We characterized plasticity of dopamine β-hydroxylase-immunoreactive NA fibers in the cerebellum of adolescent female rats that are evoked by voluntary wheel running, food restriction (FR) or by both, in combination. When 8 days of wheel access was combined with FR during the last 4 days, some responded with excessive exercise, choosing to run even during the hours of food access: this exacerbated weight loss beyond that due to FR alone. In the vermis, exercise, with or without FR, shortened the inter-varicosity intervals and increased varicosity density along NA fibers, while excessive exercise, due to FR, also shortened NA fibers. In contrast, the hemisphere required the FR-evoked excessive exercise to evoke shortened inter-varicosity intervals along NA fibers and this change was exhibited more strongly by rats that suppressed the FR-evoked excessive exercise, a behavior that minimized weight loss. Presuming that shortened inter-varicosity intervals translate to enhanced NA release and synthesis of norepinephrine, this enhancement in the cerebellar hemisphere may contribute towards protection of individuals from the life-threatening activity-based anorexia via relays with higher-order cortical areas that mediate the animal's decision to suppress the innate FR-evoked hyperactivity.

Retinal and choroidal alterations in patients with anorexia nervosa without vision loss

OBJECTIVE

Evaluate the alterations of retinal anatomy and function, as well as choroidal thickness changes, in patients with anorexia nervosa (AN).

METHOD

13 female AN patients (26 eyes) and 20 female controls (40 eyes) were included. Assessment of the retinal and choroidal anatomy was performed by optical-coherence-tomography, while multifocal-electroretinogram was used for measurements of the electrical activity of the macula. Statistical analysis was performed using t-test.

RESULTS

Central macular thickness was found to be thinner in AN (140.04 ± 14.45, 150.85 ± 16.03, p = 0.007), likewise the ganglion cell complex and outer retinal layer (ORL) at most areas. ORL superiorly was thicker in AN (169.12 ± 2.55, 163.00 ± 8.70, p < 0.001), while retinal nerve fiber layer was not different between the two groups, except the inferior region (121.08 ± 18.52, 137.60 ± 7.30, p < 0.001). Choroidal thickness was evenly diminished in the anorectic group (p = 0.001-0.027). Multifocal-electroretinogram showed lower P1-retinal response density amplitude of ring 1 in AN (159.04 ± 60.83, 292.43 ± 11.59, p < 0.001), but no significant difference concerning the P1-response density amplitude of ring 2 (79.04 ± 21.89, 82.63 ± 9.10, p = 0.36).

DISCUSSION

In AN patients, even without vision loss, significant changes occur in retinal and choroidal thickness, as well as in the electrical activity of the macula. However, this is a pilot study in a small sample that needs replication.

Structural and functional differences in the cingulate cortex relate to disease severity in anorexia nervosa

BACKGROUND

The dysfunction of specific brain areas might account for the distortion of body image in patients with anorexia nervosa. The present study was designed to reveal brain regions that are abnormal in structure and function in patients with this disorder. We hypothesized, based on brain areas of altered activity in patients with anorexia nervosa and regions involved in pain processing, an interrelation of structural aberrations in the frontoparietal-cingulate network and aberrant functional activation during thermal pain processing in patients with the disorder.

METHODS

We determined pain thresholds outside the MRI scanner in patients with anorexia nervosa and matched healthy controls. Thereafter, thermal pain stimuli were applied during fMRI imaging. Structural analyses with high-resolution structural T1-weighted volumes were performed using voxel-based morphometry and a surface-based approach.

RESULTS

Twenty-six patients and 26 controls participated in our study, and owing to technical difficulties, 15 participants in each group were included in our fMRI analysis. Structural analyses revealed significantly decreased grey matter volume and cortical thickness in the frontoparietal-cingulate network in patients with anorexia nervosa. We detected an increased blood oxygen level-dependent signal in patients during the painful 45 °C condition in the midcingulate and posterior cingulate cortex, which positively correlated with increased pain thresholds. Decreased grey matter and cortical thickness correlated negatively with pain thresholds, symptom severity and illness duration, but not with body mass index.

LIMITATIONS

The lack of a specific quantification of body image distortion is a limitation of our study.

CONCLUSION

This study provides further evidence for confined structural and functional brain abnormalities in patients with anorexia nervosa in brain regions that are involved in perception and integration of bodily stimuli. The association of structural and functional deviations with thermal thresholds as well as with clinical characteristics might indicate a common neuronal origin.

Cerebral perfusion differences in women currently with and recovered from anorexia nervosa

Anorexia nervosa is a serious psychiatric disorder characterized by restricted eating, a pursuit of thinness, and altered perceptions of body shape and size. Neuroimaging in anorexia nervosa has revealed morphological and functional alterations in the brain. A better understanding of physiological changes in anorexia nervosa could provide a brain-specific health marker relevant to treatment and outcomes. In this study, we applied several advanced magnetic resonance imaging (MRI) techniques to quantify regional and global cerebral blood flow (CBF) in 25 healthy women (HC), 23 patients currently with anorexia (AN-C) and 19 patients in long-term weight recovery following anorexia (AN-WR). Specifically, CBF was measured with pseudo-continuous arterial spin labeling (pCASL) MRI and then verified by a different technique, phase contrast (PC) MRI. Venous T2 values were determined by T2 relaxation under spin tagging (TRUST) MRI, and were used to corroborate the CBF results. These novel techniques were implemented on a standard 3T MRI scanner without any exogenous tracers, and the total scan duration was less than 10min. Voxel-wise comparison revealed that the AN-WR group showed lower CBF in bilateral temporal and frontal lobes than the AN-C group. Compared with the HC group, the AN-C group also showed higher CBF in the right temporal lobe. Whole-brain-averaged CBF was significantly decreased in the AN-WR group compared with the AN-C group, consistent with the PC-MRI results. Venous T2 values were lower in the AN-WR group than in the AN-C group, consistent with the CBF results. A review of prior work examining CBF in anorexia nervosa is included in the discussion. This study identifies several differences in the cerebral physiological alterations in anorexia nervosa, and finds specific differences relevant to the current state of the disorder.

The neurobiology of eating disorders--a clinical perspective

OBJECTIVE

To provide a neurobiological basis of eating disorders for clinicians and to enlighten how comparing neurobiology and eating disorders with neurobiology of other psychiatric illnesses can improve treatment protocols.

METHOD

A selective review on the neurobiology of eating disorders. The article focuses on clinical research on humans with consideration of the anatomical, neural, and molecular basis of eating disorders.

RESULTS

The neurobiology of people with eating disorders is altered. Many of the neurobiological regions, receptors, and chemical substrates that are affected in other mental illnesses also play an important role in eating disorders. More knowledge about the neurobiological overlap between eating disorders and other psychiatric populations will help when developing treatment protocols not the least regarding that comorbidity is common in patients with EDs.

CONCLUSION

Knowledge about the underlying neurobiology of eating disorders will improve treatment intervention and will benefit from comparisons with other mental illnesses and their treatments.

Global and regional brain volumes normalization in weight-recovered adolescents with anorexia nervosa: preliminary findings of a longitudinal voxel-based morphometry study

The recent literature on anorexia nervosa (AN) suggests that functional and structural abnormalities of cortico-limbic areas might play a role in the evolution of the disease. We explored global and regional brain volumes in a cross-sectional and follow-up study on adolescents affected by AN. Eleven adolescents with AN underwent a voxel-based morphometry study at time of diagnosis and immediately after weight recovery. Data were compared to volumes carried out in eight healthy, age and sex matched controls. Subjects with AN showed increased cerebrospinal fluid volumes and decreased white and gray matter volumes, when compared to controls. Moreover, significant regional gray matter decrease in insular cortex and cerebellum was found at time of diagnosis. No regional white matter decrease was found between samples and controls. Correlations between psychological evaluation and insular volumes were explored. After weight recovery gray matter volumes normalized while reduced global white matter volumes persisted.

Brain Dysfunctions, Psychopathologies, and Body Image Distortions

The major features in eating disorders are a preoccupation with food and its consumption and body dissatisfaction. Diagnostic manuals provide clusters of criteria according to which affected individuals can be categorized into one or other group of eating disorder. Yet, when considering the high proportion of comorbidities and ignoring the content of the symptoms (food, body), the major features seem to yield obsessional-compulsive, addictive, and impulsive qualities. In the present article, we review studies from the neuroscientific literature (mainly lesion studies) on eating disorder, obsessive-compulsive disorder, impulse control disorder, and addiction to investigate the possibility of a wider phenotype that can be related to a common brain network. The literature localizes this network to the right frontal lobe and its connectivities. This network, when dysfunctional, might result in a behavior that favors the preoccupation with particular thoughts, behaviors, anxieties, and uncontrollable urges that are accompanied by little scope for ongoing behavioral adjustments (e.g., impulse control). We reason that this network may turn out to be equally involved in understudied mental conditions of dysfunctional body processing such as muscle dysmorphia, body dysmorphic disorder (including esthetic surgery), and xelomelia. We finally consider previous notions of a wider phenotype approach to current diagnostic practice (using DSM), such as the possibility of a model with a reduced number of diagnostic categories and primary and secondary factors, and to etiological models of mental health conditions.

Increased set shifting costs in fasted healthy volunteers

We investigated the impact of temporary food restriction on a set shifting task requiring participants to judge clusters of pictures against a frequently changing rule. 60 healthy female participants underwent two testing sessions: once after fasting for 16 hours and once in a satiated state. Participants also completed a battery of questionnaires (Hospital Anxiety and Depression Scale [HADS]; Persistence, Perseveration and Perfectionism Questionnaire [PPPQ-22]; and Eating Disorders Examination Questionnaire [EDE-Q6]). Set shifting costs were significantly increased after fasting; this effect was independent of self-reported mood and perseveration. Furthermore, higher levels of weight concern predicted a general performance decrement under conditions of fasting. We conclude that relatively short periods of fasting can lead to set shifting impairments. This finding may have relevance to studies of development, individual differences, and the interpretation of psychometric tests. It also could have implications for understanding the etiology and maintenance of eating disorders, in which impaired set shifting has been implicated.

Reduced salience and default mode network activity in women with anorexia nervosa

BACKGROUND

The neurobiology of anorexia nervosa is poorly understood. Neuronal networks contributing to action selection, self-regulation and interoception could contribute to pathologic eating and body perception in people with anorexia nervosa. We tested the hypothesis that the salience network (SN) and default mode network (DMN) would show decreased intrinsic activity in women with anorexia nervosa and those who had recovered from the disease compared to controls. The basal ganglia (BGN) and sensorimotor networks (SMN) were also investigated.

METHODS

Between January 2008 and January 2012, women with restricting-type anorexia nervosa, women who recovered from the disease and healthy control women completed functional magnetic resonance imaging during a conditioned stimulus task. Network activity was studied using independent component analysis.

RESULTS

We studied 20 women with anorexia nervosa, 24 recovered women and 24 controls. Salience network activity in the anterior cingulate cortex was reduced in women with anorexia nervosa (p = 0.030; all results false-discovery rate- corrected) and recovered women (p = 0.039) compared to controls. Default mode network activity in the precuneus was reduced in women with anorexia compared to controls (p = 0.023). Sensorimotor network activity in the supplementary motor area (SMA; p = 0.008), and the left (p = 0.028) and right (p = 0.002) postcentral gyrus was reduced in women with anorexia compared to controls; SMN activity in the SMA (p = 0.019) and the right postcentral gyrus (p = 0.008) was reduced in women with anorexia compared to recovered women. There were no group differences in the BGN.

LIMITATIONS

Differences between patient and control populations (e.g., depression, anxiety, medication) are potential confounds, but were included as covariates.

CONCLUSION

Reduced SN activity in women with anorexia nervosa and recovered women could be a trait-related biomarker or illness remnant, altering the drive to approach food. The alterations in the DMN and SMN observed only in women with anorexia nervosa suggest state-dependent abnormalities that could be related to altered interoception and body image in these women when they are underweight but that remit following recovery.

The neurobiology of anorexia nervosa: a systematic review

OBJECTIVE

Recent advances in neuroimaging techniques have enabled a better understanding of the neurobiological underpinnings of anorexia nervosa (AN). The aim of this paper was to summarise our current understanding of the neurobiology of AN.

METHODS

The literature was searched using the electronic databases PubMed and Google Scholar, and by additional hand searches through reference lists and specialist eating disorders journals. Relevant studies were included if they were written in English, only used human participants, had a specific AN group, used clinical populations of AN, group comparisons were reported for AN compared to healthy controls and not merely AN compared to other eating disorders or other psychiatric groups, and were not case studies.

RESULTS

The systematic review summarises a number of structural and functional brain differences which are reported in individuals with AN, including differences in neurotransmitter function, regional cerebral blood flow, glucose metabolism, volumetrics and the blood oxygen level dependent response.

CONCLUSION

Several structural and functional differences have been reported in AN, some of which reverse and others which persist following weight restoration. These findings have important implications for our understanding of the neurobiological underpinnings of AN, and further research in this field may provide new direction for the development of more effective treatments.

Greater anterior insula activation during anticipation of food images in women recovered from anorexia nervosa versus controls

Individuals with anorexia nervosa (AN) restrict food consumption and become severely emaciated. Eating food, even thinking of eating food, is often associated with heightened anxiety. However, food cue anticipation in AN is poorly understood. Fourteen women recovered from AN and 12 matched healthy control women performed an anticipation task viewing images of food and object images during functional magnetic resonance imaging. Comparing anticipation of food versus object images between control women and recovered AN groups showed significant interaction only in the right ventral anterior insula, with greater activation in recovered AN anticipating food images. These data support the hypothesis of a disconnect between anticipating and experiencing food stimuli in recovered AN. Insula activation positively correlated with pleasantness ratings of palatable foods in control women, while no such relationship existed in recovered AN, which is further evidence of altered interoceptive function. Finally, these findings raise the possibility that enhanced anterior insula anticipatory response to food cues in recovered AN could contribute to exaggerated sensitivity and anxiety related to food and eating.

Subcallosal cingulate deep brain stimulation for treatment-refractory anorexia nervosa: a phase 1 pilot trial

BACKGROUND

Anorexia nervosa is characterised by a chronic course that is refractory to treatment in many patients and has one of the highest mortality rates of any psychiatric disorder. Deep brain stimulation (DBS) has been applied to circuit-based neuropsychiatric diseases, such as Parkinson's disease and major depression, with promising results. We aimed to assess the safety of DBS to modulate the activity of limbic circuits and to examine how this might affect the clinical features of anorexia nervosa.

METHODS

We did a phase 1, prospective trial of subcallosal cingulate DBS in six patients with chronic, severe, and treatment-refractory anorexia nervosa. Eligible patients were aged 20-60 years, had been diagnosed with restricting or binge-purging anorexia nervosa, and showed evidence of chronicity or treatment resistance. Patients underwent medical optimisation preoperatively and had baseline body-mass index (BMI), psychometric, and neuroimaging investigations, followed by implantation of electrodes and pulse generators for continuous delivery of electrical stimulation. Patients were followed up for 9 months after DBS activation, and the primary outcome of adverse events associated with surgery or stimulation was monitored at every follow-up visit. Repeat psychometric assessments, BMI measurements, and neuroimaging investigations were also done at various intervals. This trial is registered with ClinicalTrials.gov, number NCT01476540.

FINDINGS

DBS was associated with several adverse events, only one of which (seizure during programming, roughly 2 weeks after surgery) was serious. Other related adverse events were panic attack during surgery, nausea, air embolus, and pain. After 9 months, three of the six patients had achieved and maintained a BMI greater than their historical baselines. DBS was associated with improvements in mood, anxiety, affective regulation, and anorexia nervosa-related obsessions and compulsions in four patients and with improvements in quality of life in three patients after 6 months of stimulation. These clinical benefits were accompanied by changes in cerebral glucose metabolism (seen in a comparison of composite PET scans at baseline and 6 months) that were consistent with a reversal of the abnormalities seen in the anterior cingulate, insula, and parietal lobe in the disorder.

INTERPRETATION

Subcallosal cingulate DBS seems to be generally safe in this sample of patients with chronic and treatment-refractory anorexia nervosa.

FUNDING

Klarman Family Foundation Grants Program in Eating Disorders Research and Canadian Institutes of Health Research.

Insular dysfunction and descending pain inhibition in anorexia nervosa

OBJECTIVE

Reduced perception of pain is a well-established phenomenon in patients with anorexia nervosa (AN). We tested the hypothesis that altered processing of pain within the insula might account for reduced perception of pain.

METHOD

Heat pain thresholds were obtained in nineteen patients with AN and matched controls. Thereafter, a thermode was used to deliver thermal painful stimuli to the right arm during functional magnetic resonance imaging (fMRI) measurements. Stimuli were initiated for 10 s from a baseline resting temperature (32°C) to three different levels (37, 42, 45°C).

RESULTS

Significantly increased heat pain thresholds were observed in patients. A stronger activation during heat pain perception was found in the left posterior insula in controls. In contrast, higher levels of activity were shown in the ipsilateral pons in patients when compared to controls. In patients, we found a significant interrelation between the depression score (Beck depression inventory) and heat pain activations.

CONCLUSION

We suggest that reduced activity in the left posterior insula might contribute to increased pain thresholds in patients, while increased activations in the right anterior insula and pons mirror augmented sympathetic modulation putatively related to amplification of adrenergic descending pain inhibition. In addition, pain thresholds and brain activations were influenced by disease-inherent depressed mood.

[The processing of pain in psychiatric diseases]

The perception and processing of pain is disturbed in many psychiatric diseases. Some diseases are known to show decreased perception of pain (e.g. borderline personality disorder), while others are associated with augmented pain perception (e.g. alcohol and drug dependence). The close relationship between psychiatric diseases and pain is most probably caused by aberrant processing of pain in brain structures, known to be involved in psychiatric disorders as well. Aberrant perception and processing of pain in patients with anorexia nervosa (AN) will be used to demonstrate this close relationship. Dysfunction within the insula has been suggested to account for many features of AN and might contribute to reduced pain perception. Moreover, it might lead to increased adrenergic descending inhibition associated with increased sympathetic modulation. Thus, pain research might be able to alter our view on autonomic regulation, which is putatively associated with increased cardiac mortality of the disease.

What can cognitive neuroscience teach us about anorexia nervosa?

Anorexia nervosa (AN) is a complex illness and highly challenging to treat. One promising approach to significantly advance our understanding of the underlying pathophysiology of AN involves developing a cognitive neuroscience model of illness. Cognitive neuroscience uses probes such as neuropsychological tasks and neuroimaging techniques to identify the neural underpinnings of behavior. With this approach, advances have been made in identifying higher-order cognitive processes that likely mediate symptom expression in AN. Identification of related neuropathology is beginning. Such findings led to the development of complex neurobehavioral models that aim to explain the etiology and persistence of AN. Future research will use these advanced tools to test and refine hypotheses about the underlying mechanisms of AN.

Thinking about eating food activates visual cortex with reduced bilateral cerebellar activation in females with anorexia nervosa: an fMRI study

Background

Women with anorexia nervosa (AN) have aberrant cognitions about food and altered activity in prefrontal cortical and somatosensory regions to food images. However, differential effects on the brain when thinking about eating food between healthy women and those with AN is unknown.

Methods

Functional magnetic resonance imaging (fMRI) examined neural activation when 42 women thought about eating the food shown in images: 18 with AN (11 RAN, 7 BPAN) and 24 age-matched controls (HC).

Results

Group contrasts between HC and AN revealed reduced activation in AN in the bilateral cerebellar vermis, and increased activation in the right visual cortex. Preliminary comparisons between AN subtypes and healthy controls suggest differences in cortical and limbic regions.

Conclusions

These preliminary data suggest that thinking about eating food shown in images increases visual and prefrontal cortical neural responses in females with AN, which may underlie cognitive biases towards food stimuli and ruminations about controlling food intake. Future studies are needed to explicitly test how thinking about eating activates restraint cognitions, specifically in those with restricting vs. binge-purging AN subtypes.

Reward processing in anorexia nervosa

Individuals with anorexia nervosa (AN) demonstrate a relentless engagement in behaviors aimed to reduce their weight, which leads to severe underweight status, and occasionally death. Neurobiological abnormalities, as a consequence of starvation are controversial: evidence, however, demonstrates abnormalities in the reward system of patients, and recovered individuals. Despite this, a unifying explanation for reward abnormalities observed in AN and their relevance to symptoms of the illness, remains incompletely understood. Theories explaining reward dysfunction have conventionally focused on anhedonia, describing that patients have an impaired ability to experience reward or pleasure. We review taste reward literature and propose that patients' reduced responses to conventional taste-reward tasks may reflect a fear of weight gain associated with the caloric nature of the tasks, rather than an impaired ability to experience reward. Consistent with this, we propose that patients are capable of 'liking' hedonic taste stimuli (e.g., identifying them), however, they do not 'want' or feel motivated for the stimuli in the same way that healthy controls report. Recent brain imaging data on more complex reward processing tasks provide insights into fronto-striatal neural circuit dysfunction related to altered reward processing in AN that challenges the relevance of anhedonia in explaining reward dysfunction in AN. In this way, altered activity of the anterior cingulate cortex and striatum could explain patients' pathological engagement in behaviors they consider rewarding (e.g., self-starvation) that are otherwise aversive or punishing, to those without the eating disorder. Such evidence for altered patterns of brain activity associated with reward processing tasks in patients and recovered individuals may provide important information about mechanisms underlying symptoms of AN, their future investigation, and the development of treatment approaches.

Metabolic gray matter changes of adolescents with anorexia nervosa in combined MR proton and phosphorus spectroscopy

INTRODUCTION

There are hints for changes in phospholipid membrane metabolism and structure in the brain of adolescents with anorexia nervosa (AN) using either proton ((1)H) or phosphorus ((31)P) magnetic resonance spectroscopic imaging (MRSI). We aimed to specify these pathological metabolite changes by combining both methods with additional focus on the neuronal metabolites glutamate (Glu) and N-acetyl-l-aspartate (NAA).

METHODS

Twenty-one female patients (mean 14.4  ±  1.9 years) and 29 female controls (mean 16  ±  1.6 years) underwent (1)H and (31)P MRSI at 3 T applied to the centrum semiovale including the anterior cingulate cortex. We assessed gray matter (GM) and white matter (WM) metabolite concentration changes of the frontal and parietal brain measuring choline(Cho)- and ethanolamine(Eth)-containing compounds, Glutamate (Glu) and glutamine (Gln) and their sum (Glx), myoinositol, NAA, and high-energy phosphates.

RESULTS

For (1)H MRSI, a clear discrimination between GM and WM concentrations was possible, showing an increase of Glx (p < 0.001), NAA (frontal p < 0.05), pooled creatine (tCr) (p < 0.001), and choline (tCho) (p < 0.05) in the GM of AN patients. The lipid catabolites glycerophosphocholine (p < 0.07) and glycerophosphoethanolamine (p < 0.03) were increased in the parietal region.

CONCLUSIONS

Significant changes in GM metabolite concentrations were observed in AN possibly triggered by elevated excitotoxin Glu. Increased tCho may indicate modifications of membrane phospholipids due to increased catabolism in the parietal region. Since no significant changes in phosphorylated choline compounds were found for the frontal region, the tCho increase in this region may hint to fluidity changes.

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.

The cannabinoid receptor agonist THC attenuates weight loss in a rodent model of activity-based anorexia

Anorexia nervosa (AN) is characterized by anhedonia whereby patients experience little pleasure or reward in many aspects of their lives. Reward pathways and the endocannabionid system have been implicated in the mediation of food intake. The potential to exploit these systems to reverse weight loss is investigated in a rodent model of activity-based anorexia (ABA). The effect of subchronic (6 days) Δ(9)-tetrahydrocannabinol (THC) treatment (0.1, 0.5, or 2.0 mg/kg/day) was assessed on chow and high-fat diet (HFD) intake, body weight, running wheel activity (RWA) as well as thermogenesis in brown adipose tissue (BAT) and lipid metabolism in white adipose tissue (WAT). Limited time availability of food and continuous access to running wheels led to anorexia and significantly reduced body weight. THC treatment (0.5 and 2.0 mg/kg/day) transiently stimulated chow intake with a moderate effect on RWA. THC (2.0 mg/kg/day) significantly reduced body weight loss and shifted markers of thermogenesis in BAT and lipid metabolism in WAT in directions consistent with reduced energy expenditure and lipolysis. THC (2.0 mg/kg/day) combined with HFD, produced a transient increase in food intake, reduction in RWA, attenuation of body weight loss, and changes in markers of thermogensis in BAT and lipolysis in the WAT. These changes were significantly greater than those seen in vehicle (HFD), vehicle (chow), and THC (chow)-treated animals. These data show for the first time the effectiveness of the endocannabinoid system in attenuating the weight loss associated with the development of ABA via a mechanism involving reduced energy expenditure.

Brain dysfunction in anorexia nervosa: cause or consequence of under-nutrition?

PURPOSE OF REVIEW

Imaging studies that demonstrate loss of brain substance help explain why people with anorexia nervosa have cognitive deficits and may help to elucidate the cognitive style found in many patients. It is not known whether a neurobiological vulnerability predisposes to anorexia nervosa or if this is associated with maintenance of symptoms once the illness develops.

RECENT FINDINGS

Evidence emerging from functional neuro-imaging studies raise the possibility of a biological abnormality that may predispose to anorexia nervosa. Studies have found abnormal functioning in the frontal, limbic, occipital, striatal and cerebellar regions that may persist after recovery. However, most recent cross-sectional and prospective studies indicate improved cerebral activity and mixed findings in regards to neurocognitve function with recovery from anorexia nervosa.

SUMMARY

The elucidation of the neurobiology of anorexia nervosa has benefited from recent advances in neuro-imaging and cognitive neuroscience. Further research is needed to examine the degree to which abnormalities are a consequence of starvation or are caused by a putative anorexia nervosa endophenotype.

A case series investigating distinct neuropsychological profiles in children and adolescents with anorexia nervosa

A number of specific deficits in neuropsychological functioning in anorexia nervosa (AN) have been identified. However, it is not known whether these specific deficits cluster together to form one or more clear neuropsychological profiles. We present a case series of nine participants who were recruited as part of a wider, ongoing investigation of the neuropsychological profile of eating disorders (the Ravello Profile). Results show that there was a wide range of different neuropsychological profiles at initial assessment. This suggests a spectrum of neuropsychological strengths and weaknesses that would otherwise be masked in a cohort analysis. It is anticipated that factor and cluster analytic studies will establish one or more common profiles of neuropsychological deficits in AN.

Gray matter decrease distribution in the early stages of Anorexia Nervosa restrictive type in adolescents

Few studies have used Voxel-Based Morphometry (VBM) to examine brain structure in Anorexia Nervosa patients. The purpose of the present study was to investigate a sample of Anorexia Nervosa restrictive type (AN-r) adolescent patients in the early stages of the illness, using VBM in order to characterize morphometric gray matter (GM) changes. Participants were 16 AN-r female patients (with no other psychiatric disorders) whose AN-r had been in progress for less than 12 months and 16 age-matched healthy female subjects. High-resolution T1-weighted magnetic resonance images were preprocessed according to the optimized VBM method, and statistically analyzed. The analyses revealed a significant global GM decrease in the AN-r patients; furthermore, a significant region-specific decrease in GM volume was found bilaterally in the middle cingulate cortex, the precuneus, and the inferior and superior parietal lobules. The significant early GM decrease in the aforementioned regions in AN-r adolescent patients suggests that there might be a region-specific GM vulnerability that could play a role in the pathophysiology of the disease. Given that these regions are also involved in the manipulation of mental images and the mental representation of the self, this might explain the presence of a distorted body image in these patients.

Prefrontal brain function in children with anorexia nervosa: a near-infrared spectroscopy study

To investigate the prefrontal hemodynamic response during a cognitive task in childhood anorexia nervosa (AN), we measured regional cerebral blood volume changes in terms of changes in hemoglobin concentrations [Hb], using near-infrared spectroscopy (NIRS). Sixteen females with AN (mean age 14.2 years old) and 12 age-matched healthy female control subjects (mean age 14.3 years old) participated in this study. Waveform patterns for [Hb] during the word fluency task differed between the two groups, although their task performances showed no significant difference. In the control group, the [total-Hb] and [oxy-Hb] immediately increased and the [deoxy-Hb] immediately decreased after the beginning of the task and gradually reached the baseline level after the end of the task. The patients with AN were consistently characterized by an unchanged or less fluctuating response pattern of [total-Hb], [oxy-Hb] and [deoxy-Hb] during the task and rest periods. In the AN group, subjects with higher Eating Attitudes Test (EAT-26) scores showed higher [oxy-Hb] during the task. On the other hand, in the control group, subjects with higher EAT-26 scores showed lower [oxy-Hb] during the task. The grand waveforms of each [Hb] during a motor activation task, which was applied as a control task, did not differ significantly between two groups. The different prefrontal hemodynamic responses might indicate that AN subjects might apply fewer brain circuits or fewer neurons per circuit during cognitive tasks and might use different brain circuits in relation to their preoccupation with eating behaviors.