Is It Me or My Hormones? Neuroendocrine Activation Profiles to Visual Food Stimuli Across the Menstrual Cycle

The habitual degree of weight loss might be associated with specific fat and protein intakes during a period of weight maintenance in athletes used to weight variations: preliminary results from the WAVE study

Weight variations are common in sporting life, with important inter-individual variability in the degree of an athlete's habitual weight loss. As a part of the WAVE study (NCT04107545), the main objective of this preliminary study was to determine whether the habitual degree of weight loss was associated with anthropometric, body composition, nutritional or psychometric profiles during a period of weight maintenance in athletes accustomed to weight variations. We hypothesized that athletes accustomed to a higher habitual degree of weight loss may have a higher body weight and body fat mass, and may present a more controlled diet regimen and cognitive restriction than athletes with a lower habitual degree of weight loss. During a period of weight maintenance, 62 athletes (24.0 ± 5.3 years; 26 women) completed anthropometry and body composition measurements, a 48-hours food diary and self-reported questionnaires to determine their weight variation practice, nutritional profile and mood state. Athletes were stratified within inter- and intra-quartile groups according to their habitual degree of weight loss. Athletes with a higher habitual degree of weight loss were those who consumed more protein (P < .001) and less fat (P = .01) as a proportion of total energy compared with those losing less weight, without any difference in body composition between the groups. The rapid weight loss score was significantly higher in individuals losing more weight (P < .001) and no difference was observed for the mood state profile. The present results suggest a potential control of nutritional regulation during a period of weight maintenance in order to spare fat-free mass and favor fat mass loss in athletes who are routinely losing more weight. Fat-free mass may be the main nutritional driver due to low body fat mass in athletes, which may limit the "catch-up fat" phenomenon commonly observed in nonathletic population.

Electroencephalography findings in menstrually-related mood disorders: A critical review

The female reproductive years are characterized by fluctuations in ovarian hormones across the menstrual cycle, which have the potential to modulate neurophysiological and behavioral dynamics. Menstrually-related mood disorders (MRMDs) comprise cognitive-affective or somatic symptoms that are thought to be triggered by the rapid fluctuations in ovarian hormones in the luteal phase of the menstrual cycle. MRMDs include premenstrual syndrome (PMS), premenstrual dysphoric disorder (PMDD), and premenstrual exacerbation (PME) of other psychiatric disorders. Electroencephalography (EEG) non-invasively records in vivo synchronous activity from populations of neurons with high temporal resolution. The present overview sought to systematically review the current state of task-related and resting-state EEG investigations on MRMDs. Preliminary evidence indicates lower alpha asymmetry at rest being associated with MRMDs, while one study points to the effect being luteal-phase specific. Moreover, higher luteal spontaneous frontal brain activity (slow/fast wave ratio as measured by the delta/beta power ratio) has been observed in persons with MRMDs, while sleep architecture results point to potential circadian rhythm disturbances. In this review, we discuss the quality of study designs as well as future perspectives and challenges of supplementing the diagnostic and scientific toolbox for MRMDs with EEG.

Hypothalamic Reactivity and Connectivity following Intravenous Glucose Administration

Dysfunctional glucose sensing in homeostatic brain regions such as the hypothalamus is interlinked with the pathogenesis of obesity and type 2 diabetes mellitus. However, the physiology and pathophysiology of glucose sensing and neuronal homeostatic regulation remain insufficiently understood. To provide a better understanding of glucose signaling to the brain, we assessed the responsivity of the hypothalamus (i.e., the core region of homeostatic control) and its interaction with mesocorticolimbic brain regions in 31 normal-weight, healthy participants. We employed a single-blind, randomized, crossover design of the intravenous infusion of glucose and saline during fMRI. This approach allows to investigate glucose signaling independent of digestive processes. Hypothalamic reactivity and connectivity were assessed using a pseudo-pharmacological design and a glycemia-dependent functional connectivity analysis, respectively. In line with previous studies, we observed a hypothalamic response to glucose infusion which was negatively related to fasting insulin levels. The observed effect size was smaller than in previous studies employing oral or intragastric administration of glucose, demonstrating the important role of the digestive process in homeostatic signaling. Finally, we were able to observe hypothalamic connectivity with reward-related brain regions. Given the small amount of glucose employed, this points toward a high responsiveness of these regions to even a small energy stimulus in healthy individuals. Our study highlights the intricate relationship between homeostatic and reward-related systems and their pronounced sensitivity to subtle changes in glycemia.

Effect of transcranial direct current stimulation on homeostatic and hedonic appetite control and mood states in women presenting premenstrual syndrome across menstrual cycle phases

PURPOSE

This study investigated the acute effect of anodal transcranial direct current stimulation (a-tDCS) over the left dorsolateral prefrontal cortex (DLPFC) on appetite, energy intake, food preferences, and mood states in the luteal and follicular phases of the menstrual cycle in women presenting premenstrual syndrome.

METHODS

Sixteen women (26.5 ± 5.2 years; 1.63 ± 0.1 m; 64.2 ± 12.8 kg; body mass index 24.0 ± 5.0 kg/m²; body fat 27.6 ± 7.5%) with the eumenorrheic menstrual cycle were submitted to a-tDCS and sham-tDCS conditions over their follicular and luteal phases. At pre - and post-tDCS, hunger and desire to eat something tasty, (analogic visual scale), the profile of mood states (POMS), and the psychological components of food preferences (Leeds Food Preference Questionnaire-BR) were assessed. Participants recorded their food intake for the rest of the day using a diary log.

RESULTS

There was a trend towards main effect of condition for decreased implicit wanting for low-fat savory food after a-tDCS but not sham-tDCS regardless of menstrual cycle phase (p = 0.062). There was no effect for self-reported hunger, desire to eat, energy and macronutrient intake, and on other components of food preferences (explicit liking and wanting for low- and high-fat savory and sweet foods, implicit wanting for low- and high-fat sweet and high-fat savory food); as well as for mood states.

CONCLUSIONS

Although no significant effects of a-tDCS were found, the present investigation provides relevant perspectives for future studies.

Progesterone and contraceptive progestin actions on the brain: A systematic review of animal studies and comparison to human neuroimaging studies

In this review we systematically summarize the effects of progesterone and synthetic progestins on neurogenesis, synaptogenesis, myelination and six neurotransmitter systems. Several parallels between progesterone and older generation progestin actions emerged, suggesting actions via progesterone receptors. However, existing results suggest a general lack of knowledge regarding the effects of currently used progestins in hormonal contraception regarding these cellular and molecular brain parameters. Human neuroimaging studies were reviewed with a focus on randomized placebo-controlled trials and cross-sectional studies controlling for progestin type. The prefrontal cortex, amygdala, salience network and hippocampus were identified as regions of interest for future preclinical studies. This review proposes a series of experiments to elucidate the cellular and molecular actions of contraceptive progestins in these areas and link these actions to behavioral markers of emotional and cognitive functioning. Emotional effects of contraceptive progestins appear to be related to 1) alterations in the serotonergic system, 2) direct/indirect modulations of inhibitory GABA-ergic signalling via effects on the allopregnanolone content of the brain, which differ between androgenic and anti-androgenic progestins. Cognitive effects of combined oral contraceptives appear to depend on the ethinylestradiol dose.

Hormonal contraceptives and the brain: A systematic review on 60 years of neuroimaging, EEG, and biochemical studies in humans and animals

Hormonal contraception has been widely prescribed for decades. Although safety and efficacy are well-established, much uncertainty remains regarding brain effects of hormonal contraception. We systematically review human and animal studies on the brain effects of hormonal contraception which employed neuroimaging techniques such as MRI, PET and EEG, as well as animal studies which reported on neurotransmitter and other brain biochemical effects. We screened 1001 articles and ultimately extracted data from 70, comprising 51 human and 19 animal studies. Of note, there were no animal studies which employed structural or functional MRI, MRS or PET. In summary, our review shows hormonal contraceptive associations with changes in the brain have been documented. Many questions remain and more studies are needed to describe the effects of hormonal contraception on the brain.

Food preferences throughout the menstrual cycle - A computer-assisted neuro-endocrino-psychological investigation

BACKGROUND

As eating behavior changes in relation to the menstrual cycle and weight changes with menopausal transition, ovarian hormones appear to be involved in regulating eating behavior. However, observations are contradictory and are difficult to compare, due to methodological problems related to nutritional epidemiology. To better understand the relationship between ovarian steroid hormones and eating behavior, our study evaluates women's responses to visual food cues at different points in the menstrual cycle with their specific serum estrogen/progesterone levels and women's responses in the case of strong estrogen changes in the context of fertility treatments.

METHODS

We collected data from 129 women, 44 of whom received in vitro fertilization (IVF) at the Department of Reproductive Endocrinology, University Hospital Zurich. A total of 85 women with natural cycles were recruited at the University Hospital Zurich (n = 37) and at the Hannover Medical School (n = 48). Our observational study used 4 different measurement time points across the natural cycle and 2 measurement time points in women with supraphysiological estradiol levels during fertility treatments. Using a second cycle, we then tested our results for replication. At these predefined time points, women were shown pictures of 11 categories of food, with 4 items for each category and blood samples for measurement of hormone levels were taken. Food preferences registered at the time of the investigation were indicated on a visual analogue scale (0-100).

RESULTS

We did not find any statistically significant association between women's serum hormone levels and the rating of visually presented food, either during the menstrual cycle or during fertility treatments after controlling for multiple testing (all p > 0.005). Ratings for fruits, vegetables, and carbohydrates showed a significant linear decline throughout the first menstrual cycle (p < 0.01), which did not replicate in the second cycle (p > 0.05). In contrast, the ratings for sweets showed a significant linear decline in both cycles (both p < 0.01), with a mean rating of 54.2 and 48.8 in the menstrual phase of the first and second cycle, respectively, to a mean rating of 47.7 and 43.4 in the premenstrual phase of the first and second cycle, respectively. During fertility treatments, no food rating showed a significant change (all p > 0.05). Mood such as negative and positive affects did not influence ratings for visual food cues neither throughout the menstrual cycles nor during fertility treatment.

CONCLUSIONS

Serum levels of estradiol and progesterone do not correlate with food ratings in women, even when estradiol levels are above the physiological level of a natural menstrual cycle. Since, except for sweets, significant changes in food ratings in a first cycle did not replicate in a second menstrual cycle, significant findings from the literature based on animal or human studies focusing on a single-cycle have to be interpreted with caution.

Combined oral contraceptive use and risk for binge eating in women: Potential gene × hormone interactions

Extant animal and human data suggest endogenous ovarian hormones increase risk for binge eating in females, possibly via gene × hormone interactions and hormonally induced increases in genetic influences. Approximately 85 % of women will take combined oral contraceptives (COCs) that mimic the riskiest hormonal milieu for binge eating (i.e., post-ovulation when both estrogen and progesterone are present). The purpose of this narrative review is to synthesize findings of binge eating risk in COC users. Few studies have been conducted, but results suggest that COCs may increase risk for binge eating and related phenotypes (e.g., craving for sweets), particularly in genetically vulnerable women. Larger, more systematic human and animal studies of COCs and binge eating are needed. The goal of this work should be to advance personalized medicine by identifying the extent of COC risk as well as the role of gene × hormone interactions in susceptibility.

Attentional bias towards appealing and disgusting food cues varies with the menstrual cycle

Ovarian hormonal changes along the female menstrual cycle are believed to adapt women to the external environment through various adaptive strategies, including modulating appetite and eating behavior. We aimed to compare food-associated behavioral responses between two distinct menstrual phases (late follicular vs. mid-luteal) and investigate the underlying neural mechanism. Attentional bias towards visual food cues was repeatedly measured in 29 healthy young women during these two menstrual phases in a counterbalanced manner. Combining an emotional dot-probe task with frequency-tagged electroencephalography (EEG), we confirmed that the menstrual cycle modulated healthy women's attentional bias towards appealing and disgusting food cues. Women in the mid-luteal phase showed more avoidance of disgusting food cues, as reflected by a significantly longer response time. Steady-state visual evoked potential (SSVEP) results indicated that they exhibited a trend of transiently enhanced attentional bias towards appealing food cues and another trend of speeded attentional withdrawal from disgusting food cues during the mid-luteal phase relative to the late follicular phase, albeit non-significant after correction for multiple testing. Moreover, a significantly larger P3 amplitude was evoked by probes following the presentation of disgusting food cues in the mid-luteal phase than the late follicular phase. These findings indicate divergent attentional deployments on emotional food cues across menstrual phases and suggest the mid-luteal phase as a relatively sensitive stage in the menstrual cycle for women to regulate their appetite and eating behavior.

Ovarian steroid hormones: A long overlooked but critical contributor to brain aging and Alzheimer's disease

Ovarian hormones, particularly 17β-estradiol, are involved in numerous neurophysiological and neurochemical processes, including those subserving cognitive function. Estradiol plays a key role in the neurobiology of aging, in part due to extensive interconnectivity of the neural and endocrine system. This aspect of aging is fundamental for women's brains as all women experience a drop in circulating estradiol levels in midlife, after menopause. Given the importance of estradiol for brain function, it is not surprising that up to 80% of peri-menopausal and post-menopausal women report neurological symptoms including changes in thermoregulation (vasomotor symptoms), mood, sleep, and cognitive performance. Preclinical evidence for neuroprotective effects of 17β-estradiol also indicate associations between menopause, cognitive aging, and Alzheimer's disease (AD), the most common cause of dementia affecting nearly twice more women than men. Brain imaging studies demonstrated that middle-aged women exhibit increased indicators of AD endophenotype as compared to men of the same age, with onset in perimenopause. Herein, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining cognition in women, with evidence implicating menopause-related declines in 17β-estradiol in cognitive aging and AD risk. We will review research focused on the role of endogenous and exogenous estrogen exposure as a key underlying mechanism to neuropathological aging in women, with a focus on whether brain structure, function and neurochemistry respond to hormone treatment. While still in development, this research area offers a new sex-based perspective on brain aging and risk of AD, while also highlighting an urgent need for better integration between neurology, psychiatry, and women's health practices.

HPA axis activity across the menstrual cycle - a systematic review and meta-analysis of longitudinal studies

Differential HPA axis function has been proposed to underlie sex-differences in mental disorders; however, the impact of fluctuating sex hormones across the menstrual cycle on HPA axis activity is still unclear. This meta-analysis investigated basal cortisol concentrations as a marker for HPA axis activity across the menstrual cycle. Through a systematic literature search of five databases, 121 longitudinal studies were included, summarizing data of 2641 healthy, cycling participants between the ages of 18 and 45. The meta-analysis showed higher cortisol concentrations in the follicular vs. luteal phase (d_SMC = 0.12, p =.004, [0.04 - 0.20]). Comparisons between more precise cycle phases were mostly insignificant, aside from higher concentrations in the menstrual vs. premenstrual phase (d_SMC = 0.17, [0.02 - 0.33], p =.03). In all included studies, nine samples used established cortisol parameters to indicate HPA axis function, specifically diurnal profiles (k = 4) and the cortisol awakening response (CAR) (k = 5). Therefore, the meta-analysis highlights the need for more rigorous investigation of HPA axis activity and menstrual cycle phase.

Behavioral Symptomatology in the Premenstruum

OBJECTIVE

Sleep and eating behaviors are disturbed during the premenstrual phase of the menstrual cycle in a significant number of reproductive-age women. Despite their impact on the development and control of chronic health conditions, these behaviors are poorly understood. In the present study, we sought to identify affective and psychological factors which associate with premenstrual changes in sleeping and eating behaviors and assess how they impact functionality.

METHODS

Fifty-seven women provided daily ratings of premenstrual symptomatology and functionality across two-three menstrual cycles (156 cycles total). For each participant and symptom, we subtracted the mean day +5 to +10 ("post-menstruum") ratings from mean day -6 to -1 ("pre-menstruum") ratings and divided this value by participant- and symptom-specific variance. We completed the statistical analysis using multivariate linear regression.

RESULTS

Low interest was associated with a premenstrual increase in insomnia (p ≤ 0.05) and appetite/eating (p ≤ 0.05). Furthermore, insomnia was associated with occupational (p ≤ 0.001), recreational (p ≤ 0.001), and relational (p ≤ 0.01) impairment.

CONCLUSIONS

Results of the present analysis highlight the importance of apathy (i.e., low interest) on the expression of behavioral symptomatology, as well as premenstrual insomnia on impairment. These findings can inform treatment approaches, thereby improving care for patients suffering from premenstrual symptomatology linked to chronic disease conditions.

Waist Circumference and Its Association With Premenstrual Food Craving: The PHASE Longitudinal Study

Visceral adiposity is a significant marker of all-cause mortality. Reproductive age women are at a considerable risk for developing visceral adiposity; however, the associated factors are poorly understood. The proposed study evaluated whether food craving experienced during the premenstrual period is associated with waist circumference. Forty-six women (mean BMI = 24.36) prospectively provided daily ratings of food craving across two-three menstrual cycles (122 cycles total). Their premenstrual rating of food craving was contrasted against food craving in the follicular phase to derive a corrected summary score of the premenstrual food craving increase. Study groups were divided into normal (n = 26) and obese (n = 20) based on the 80 cm waist circumference cutoff signifying an increase in risk. Waist circumference category was significantly associated with premenstrual food cravings [F _(1,44) = 5.12, p = 0.028]. Post hoc comparisons using the Tukey HSD test (95% family-wise confidence level) showed that the mean score for the food craving effect size was 0.35 higher for the abdominally obese vs. normal study groups (95% CI: 0.039 to 0.67). The result was statistically significant even following inclusion of BMI in the model, pointing to a particularly dangerous process of central fat accumulation. The present study establishes an association between temporal vulnerability to an increased food-related behavior and a marker of metabolic abnormality risk (i.e., waist circumference), thereby forming a basis for integrating the premenstruum as a viable intervention target for this at-risk sex and age group.

Effect of oral contraceptives on energy balance in women: A review of current knowledge and potential cellular mechanisms

Body weight management is currently of major concern as the obesity epidemic is still a worldwide challenge. As women face more difficulties to lose weight than men, there is an urgent need to better understand the underlying reasons and mechanisms. Recent data have suggested that the use of oral contraceptive (OC) could be involved. The necessity of utilization and development of contraceptive strategies for birth regulation is undeniable and contraceptive pills appear as a quite easy approach. Moreover, OC also represent a strategy for the management of premenstrual symptoms, acne or bulimia nervosa. The exact impact of OC on body weight remains not clearly established. Thus, after exploring the potential underlying mechanisms by which OC could influence the two side of energy balance, we then provide an overview of the available evidence regarding the effects of OC on energy balance (i.e. energy expenditure and energy intake). Finally, we highlight the necessity for future research to clarify the cellular effects of OC and how the individualization of OC prescriptions can improve long-term weight loss management.

No Differences in Value-Based Decision-Making Due to Use of Oral Contraceptives

Fluctuating ovarian hormones have been shown to affect decision-making processes in women. While emerging evidence suggests effects of endogenous ovarian hormones such as estradiol and progesterone on value-based decision-making in women, the impact of exogenous synthetic hormones, as in most oral contraceptives, is not clear. In a between-subjects design, we assessed measures of value-based decision-making in three groups of women aged 18 to 29 years, during (1) active oral contraceptive intake (N = 22), (2) the early follicular phase of the natural menstrual cycle (N = 20), and (3) the periovulatory phase of the natural menstrual cycle (N = 20). Estradiol, progesterone, testosterone, and sex-hormone binding globulin levels were assessed in all groups via blood samples. We used a test battery which measured different facets of value-based decision-making: delay discounting, risk-aversion, risk-seeking, and loss aversion. While hormonal levels did show the expected patterns for the three groups, there were no differences in value-based decision-making parameters. Consequently, Bayes factors showed conclusive evidence in support of the null hypothesis. We conclude that women on oral contraceptives show no differences in value-based decision-making compared to the early follicular and periovulatory natural menstrual cycle phases.

Genetically-predicted prefrontal DRD4 gene expression modulates differentiated brain responses to food cues in adolescent girls and boys

The dopamine receptor 4 (DRD4) in the prefrontal cortex (PFC) acts to modulate behaviours including cognitive control and motivation, and has been implicated in behavioral inhibition and responsivity to food cues. Adolescence is a sensitive period for the development of habitual eating behaviors and obesity risk, with potential mediation by development of the PFC. We previously found that genetic variations influencing DRD4 function or expression were associated with measures of laboratory and real-world eating behavior in girls and boys. Here we investigated brain responses to high energy–density (ED) and low-ED food cues using an fMRI task conducted in the satiated state. We used the gene-based association method PrediXcan to estimate tissue-specific DRD4 gene expression in prefrontal brain areas from individual genotypes. Among girls, those with lower vs. higher predicted prefrontal DRD4 expression showed lesser activation to high-ED and low-ED vs. non-food cues in a distributed network of regions implicated in attention and sensorimotor processing including middle frontal gyrus, and lesser activation to low-ED vs non-food cues in key regions implicated in valuation including orbitofrontal cortex and ventromedial PFC. In contrast, males with lower vs. higher predicted prefrontal DRD4 expression showed minimal differences in food cue response, namely relatively greater activation to high-ED and low-ED vs. non-food cues in the inferior parietal lobule. Our data suggest sex-specific effects of prefrontal DRD4 on brain food responsiveness in adolescence, with modulation of distributed regions relevant to cognitive control and motivation observable in female adolescents.

Food addiction symptoms are related to neuroaffective responses to preferred binge food and erotic cues

It has been proposed that some individuals succumb to maladaptive eating behaviors because, like those with addiction, they attribute high incentive salience to food-associated cues. Here, we tested whether women that attribute high incentive salience to food-associated cues report high food addiction symptomatology. In 76 college women, we assessed self-reported food addiction symptoms using the Yale Food Addiction Scale and we recorded event-related potentials (ERPs, a direct measure of brain activity) to preferred food, erotic, unpleasant, and neutral images. We used the amplitude of the late positive potential (LPP, a component of the ERPs) as an index of the incentive salience attributed to the images. Using a multivariate classification algorithm (k-means cluster analysis), we identified two neuroaffective reactivity profiles that have been previously associated with individual differences in the tendency to attribute incentive salience to cues and with differences in vulnerability to addictive behaviors. Results showed that women with elevated LPP responses to preferred food cues relative to erotic images report higher food addiction symptoms than women with low LPP responses to preferred food cues relative to other motivationally relevant stimuli. These results support the hypothesis that individual differences in the tendency to attribute incentive salience to food cues play an important role in modulating food addiction symptomatology.

Increased Brain Reward Responsivity to Food-Related Odors in Obesity

OBJECTIVE

Food odors serve as powerful stimuli signaling the food quality and energy density and direct food-specific appetite and consumption. This study explored obesity-related brain activation in response to odors related to high- or low-energy-dense foods.

METHODS

Seventeen participants with obesity (BMI > 30 kg/m² ; 4 males and 13 females) and twenty-one with normal weight (BMI < 25 kg/m² ; 9 males and 12 females) underwent a functional magnetic resonance imaging scan in which they received chocolate (high-energy-dense food) and cucumber (low-energy-dense food) odor stimuli. Participants' olfactory and gustatory functions were assessed by the "Sniffin' Sticks" and "Taste Strips" tests, respectively.

RESULTS

Compared with normal-weight controls, participants with obesity had lower odor sensitivity (phenylethyl alcohol) and decreased odor discrimination ability. However, participants with obesity demonstrated greater brain activation in response to chocolate compared with cucumber odors in the bilateral inferior frontal operculum and cerebellar vermis, right ventral anterior insula extending to putamen, right middle temporal gyrus, and right supramarginal areas.

CONCLUSIONS

The present study provides preliminary evidence that obesity is associated with heightened brain activation of the reward and flavor processing areas in response to chocolate versus cucumber odors, possibly because of the higher energy density and reinforcing value of chocolate compared with cucumber.

Ovarian Hormones and Reward Processes in Palatable Food Intake and Binge Eating

Ovarian hormones are associated with risk for binge eating in women. Recent animal and human studies suggest that food-related reward processing may be one set of neurobiological factors that contribute to these relationships, but additional studies are needed to confirm and extend findings.

Neuroimaging of hypothalamic mechanisms related to glucose metabolism in anorexia nervosa and obesity

BACKGROUNDGiven the heightened tolerance to self-starvation in anorexia nervosa (AN), a hypothalamic dysregulation of energy and glucose homeostasis has been hypothesized. Therefore, we investigated whether hypothalamic reactivity to glucose metabolism is impaired in AN.METHODSTwenty-four participants with AN, 28 normal-weight participants, and 24 healthy participants with obesity underwent 2 MRI sessions in a single-blind, randomized, case-controlled crossover study. We used an intragastric infusion of glucose and water to bypass the cephalic phase of food intake. The responsivity of the hypothalamus and the crosstalk of the hypothalamus with reward-related brain regions were investigated using high-resolution MRI.RESULTSNormal-weight control participants displayed the expected glucose-induced deactivation of hypothalamic activation, whereas patients with AN and participants with obesity showed blunted hypothalamic reactivity. Furthermore, patients with AN displayed blunted reactivity in the nucleus accumbens and amygdala. Compared with the normal-weight participants and control participants with obesity, the patients with AN failed to show functional connectivity between the hypothalamus and the reward-related brain regions during water infusion relative to glucose infusion. Finally, the patients with AN displayed typical baseline levels of peripheral appetite hormones during a negative energy balance.CONCLUSIONThese results indicate that blunted hypothalamic glucose reactivity might be related to the pathophysiology of AN. This study provides insights for future research, as it is an extended perspective of the traditional primary nonhomeostatic understanding of the disease.FUNDINGThis study was supported by a grant from the DFG (SI 2087/2-1).

Neuroimaging the menstrual cycle: A multimodal systematic review

Increasing evidence indicates that ovarian hormones affect brain structure, chemistry and function of women in their reproductive age, potentially shaping their behavior and mental health. Throughout the reproductive years, estrogens and progesterone levels fluctuate across the menstrual cycle and can modulate neural circuits involved in affective and cognitive processes. Here, we review seventy-seven neuroimaging studies and provide a comprehensive and data-driven evaluation of the accumulating evidence on brain plasticity associated with endogenous ovarian hormone fluctuations in naturally cycling women (n = 1304). The results particularly suggest modulatory effects of ovarian hormones fluctuations on the reactivity and structure of cortico-limbic brain regions. These findings highlight the importance of performing multimodal neuroimaging studies on neural correlates of systematic ovarian hormone fluctuations in naturally cycling women based on careful menstrual cycle staging.

Homeostasis and food craving in obesity: a functional MRI study

OBJECTIVES

Food intake in obesity has been found to be reward-based and less contingent on homeostatic needs. Accordingly, previous studies investigating neural processing of food cues observed aberrant processing in reward- and control-related brain regions in obesity. To further investigate the relation between homeostasis and food intake, this study investigated the influence of glucose metabolism on the neuronal response during the regulation of food craving in participants with obesity.

METHODS

Twenty-five normal-weight and 25 women with obesity were examined on two occasions after receiving either water or glucose directly into the stomach using a nasogastric tube. Participants were blinded to the type of infusion and were required to refrain from eating for 16 h before each visit. An event-related fMRI paradigm was used to investigate the effect of intestinal glucose load on the neuronal response during the regulation of food craving.

RESULTS

A 2 × 2 mixed-model ANOVA revealed that craving regulation was associated with increased activation in fronto-parietal regions in participants with obesity when compared to healthy controls. However, this effect was observed independently from homeostatic satiety. A regression analysis revealed that the reduction of food craving was related to increased activation in the lingual gyrus in individuals with obesity following the infusion of water.

CONCLUSIONS

In participants with obesity, the neuronal response during the regulation of food craving is associated with increased neural cognitive top-down control and increased visual food processing. Since this observation was independent from satiety status, our results indicate a reduced influence of homeostasis on neural processing during food craving in obesity. This study was registered on clinicaltrials.org: NCT03075371.

The Effects of Hormonal Contraceptives on the Brain: A Systematic Review of Neuroimaging Studies

Background: Hormonal contraceptive drugs are being used by adult and adolescent women all over the world. Convergent evidence from animal research indicates that contraceptive substances can alter both structure and function of the brain, yet such effects are not part of the public discourse or clinical decision-making concerning these drugs. We thus conducted a systematic review of the neuroimaging literature to assess the current evidence of hormonal contraceptive influence on the human brain.

Methods: The review was registered in PROSPERO and conducted in accordance with the PRISMA criteria for systematic reviews. Structural and functional neuroimaging studies concerning the use of hormonal contraceptives, indexed in Embase, PubMed and/or PsycINFO until February 2020 were included, following a comprehensive and systematic search based on predetermined selection criteria.

Results: A total of 33 articles met the inclusion criteria. Ten of these were structural studies, while 23 were functional investigations. Only one study investigated effects on an adolescent sample. The quality of the articles varied as many had methodological challenges as well as partially unfounded theoretical claims. However, most of the included neuroimaging studies found functional and/or structural brain changes associated with the use of hormonal contraceptives.

Conclusion: The included studies identified structural and functional changes in areas involved in affective and cognitive processing, such as the amygdala, hippocampus, prefrontal cortex and cingulate gyrus. However, only one study reported primary research on a purely adolescent sample. Thus, there is a need for further investigation of the implications of these findings, especially with regard to adolescent girls.

Food cue-elicited brain potentials change throughout menstrual cycle: Modulation by eating styles, negative affect, and premenstrual complaints

BACKGROUND

While there is evidence for increased food intake and craving during the luteal phase, underlying mechanisms are incompletely understood. The present study investigated electrophysiological responses to food pictures as a function of menstrual cycle phase. In addition, the moderating effects of progesterone, eating behaviors (restraint, emotional, orthorexic), negative affect, and premenstrual complaints were explored.

METHODS

Using a within-subject design, 35 free-cycling women watched and rated pictures of food (high and low caloric) and control items during the follicular, the ovulatory, and the luteal phase (counterbalanced), while EEG was recorded to examine the late positive potentials (LPP). Salivary gonadal hormones and affect were examined at each occasion. Eating behaviors and premenstrual complaints were assessed once.

RESULTS

For parietal regions, average LPPs were comparable between cycle phases but slightly larger LPP amplitudes were elicited by high caloric food pictures as compared to the neutral category. Descriptively, both food categories elicited larger parietal LPPs than neutral pictures during the luteal phase. Analyses of LPPs for central-parietal regions showed no effect of picture category or cycle phase, except higher amplitudes in the right area during the luteal phase. During the luteal phase, progesterone and functional interference from premenstrual symptoms (but not age, BMI, picture ratings, affect, estradiol, or eating behaviors) significantly predicted larger parietal LPPs towards high caloric (but not low caloric) pictures.

CONCLUSION

Our findings suggest a heightened food cue reactivity during the luteal phase, which may relate to higher ovarian hormone secretion and more functional impact of premenstrual symptoms. This research contributes to a better understanding of menstrual health and the identification of preventive strategies for premenopausal women.

Sex and region-specific effects of high fat diet on PNNs in obesity susceptible rats

Perineuronal nets (PNNs) are specialized extracellular matrix structures that primarily surround fast-spiking parvalbumin (PV)-containing interneurons within the PFC. They regulate PV neuron function and plasticity to maintain cortical excitatory/inhibitory balance. For example, reductions in PNN intensity are associated with reduced local inhibition and enhanced pyramidal neuron firing. We previously found that exposure to dietary high fat reduced PNN intensity within the PFC of male Sprague-Dawley (SD) rats. However, how high fat affects PNNs in the PFC of females or in obesity-vulnerable vs. -resistant models is unknown. Therefore, we gave male and female SD, selectively bred obesity-prone (OP), and obesity-resistant rats (OR) free access to standard lab chow or 60% high fat for 21 days. We then measured the number of PNN positive cells and PNN intensity (determined by Wisteria floribunda agglutinin [WFA] staining) as well as the number of PV positive neurons using immunohistochemistry. We found sex and region-specific effects of dietary high fat on PNN intensity, in the absence of robust changes in cell number. Effects were comparable in SD and OP but differed in OR rats. Specifically, high fat reduced PNN intensities in male SD and OP rats but increased PNN intensities in female SD and OP rats. In contrast, effects in ORs were opposite, with males showing increases in PNN intensity and females showing a reduction in intensity. Finally, these effects were also region specific, with diet-induced reductions in PNN intensity found in the prelimbic PFC (PL-PFC) and ventral medial orbital frontal cortex (vmOFC) of SD and OP males in the absence of changes in the infralimbic PFC (IL-PFC), and increases in PNN intensity in the IL-PFC of SD and OP females in the absence of changes in other regions. These results are discussed in light of roles PNNs may play in influencing PFC neuronal activity and the differential role of these sub-regions in food-seeking and motivation.

Oxytocin reduces the functional connectivity between brain regions involved in eating behavior in men with overweight and obesity

Background:

Oxytocin (OXT), shown to decrease food intake in animal models and men, is a promising novel treatment for obesity. We have shown that in men with overweight and obesity, intranasal (IN) OXT reduced the functional magnetic resonance imaging (fMRI) blood oxygenation level-dependent signal in the ventral tegmental area (VTA), the origin of the mesolimbic dopaminergic reward system, in response to high-calorie food vs. non-food images. Here, we employed functional connectivity fMRI analysis, which measures the synchrony in activation between neural systems in a context-dependent manner. We hypothesized that OXT would attenuate the functional connectivity of the VTA with key food motivation brain areas only when participants viewed high-calorie food stimuli.

Methods:

This randomized, double-blind, placebo-controlled crossover study of 24 IU IN OXT included 10 men with overweight or obesity (mean±SEM BMI: 28.9±0.8 kg/m²). Following drug administration, subjects completed an fMRI food motivation paradigm including images of high and low-calorie foods, non-food objects, and fixation stimuli. A psychophysiological interaction analysis was performed with the VTA as seed region.

Results:

Following OXT administration, compared with placebo, participants exhibited significantly attenuated functional connectivity between the VTA and the insula, oral somatosensory cortex, amygdala, hippocampus, operculum, and middle temporal gyrus in response to viewing high-calorie foods (Z≥3.1, cluster-corrected, p<0.05). There was no difference in functional connectivity between VTA and these brain areas when comparing OXT and placebo for low-calorie food, non-food, and fixation images.

Conclusion:

In men with overweight and obesity, OXT attenuates the functional connectivity between the VTA and food motivation brain regions in response to high-calorie visual food images. These findings could partially explain the observed anorexigenic effect of OXT, providing insight into the mechanism through which OXT ameliorates food cue-induced reward anticipation in patients with obesity. Additional studies are ongoing to further delineate the anorexigenic effect of OXT in obesity.

Effects of Hormonal Contraceptives on Mood: A Focus on Emotion Recognition and Reactivity, Reward Processing, and Stress Response

PURPOSE OF REVIEW

We review recent research investigating the relationship of hormonal contraceptives and mood with a focus on relevant underlying mechanisms, such as emotion recognition and reactivity, reward processing, and stress response.

RECENT FINDINGS

Adverse effects of hormonal contraceptives (HCs) on mood seem most consistent in women with a history of depressive symptoms and/or previous negative experience with HC-intake. Current evidence supports a negativity bias in emotion recognition and reactivity in HC-users, although inconsistent to some extent. Some data, however, do indicate a trend towards a blunted reward response and a potential dysregulation of the stress response in some HC-users. HC-effects on psychological and neurophysiological mechanisms underlying mood are likely context-dependent. We provide suggestions on how to address some of the contributing factors to this variability in future studies, such as HC-dose, timing, administration-mode, and individual risk. A better understanding of how and when HCs affect mood is critical to provide adequate contraceptive choices to women worldwide.

Effects of the estrous cycle and ovarian hormones on cue-triggered motivation and intrinsic excitability of medium spiny neurons in the Nucleus Accumbens core of female rats

Naturally occurring alterations in estradiol influence food intake in females. However, how motivational responses to food cues are affected by the estrous cycle or ovarian hormones is unknown. In addition, while individual susceptibility to obesity is accompanied by enhanced incentive motivational responses to food cues and increased NAc intrinsic excitability in males, studies in females are absent. Therefore, we examined basal differences in intrinsic NAc excitability of obesity-prone vs. obesity-resistant females and determined how conditioned approach (a measure of cue-triggered motivation), food intake, and motivation for food vary with the cycle in naturally cycling female obesity-prone, obesity-resistant, and outbred Sprague-Dawley rats. Finally, we used ovariectomy followed by hormone treatment to determine the role of ovarian hormones in cue-triggered motivation in selectively-bred and outbred female rats. We found that intrinsic excitability of NAc MSNs and conditioned approach are enhanced in female obesity-prone vs. obesity-resistant rats. These effects were driven by greater MSN excitability and conditioned approach behavior during metestrus/diestrus vs. proestrus/estrus in obesity-prone but not obesity-resistant rats, despite similar regulation of food intake and food motivation by the cycle in these groups. Furthermore, estradiol and progesterone treatment reduced conditioned approach behavior in obesity-prone and outbred Sprague-Dawley females. To our knowledge, these data are the first to demonstrate cycle- and hormone-dependent effects on the motivational response to a food cue, and the only studies to date to determine how individual susceptibility to obesity influences NAc excitability, cue-triggered food-seeking, and differences in the regulation of these neurobehavioral responses by the estrous cycle.

Greater Reward-Related Neuronal Response to Hedonic Foods in Women Compared with Men

OBJECTIVE

The current study aimed to identify how sex influences neurobiological responses to food cues, particularly those related to hedonic eating, and how this relates to obesity propensity, using functional magnetic resonance imaging (fMRI).

METHODS

Adult men and women who were either obesity resistant (OR) or obesity prone (OP) underwent fMRI while viewing visual food cues (hedonic foods, neutral foods, and nonfood objects) in both fasted and fed states.

RESULTS

When fasted, a significant sex effect on the response to hedonic vs. neutral foods was observed, with greater responses in women than men in the nucleus accumbens (P = 0.0002) and insula (P = 0.010). Sex-based differences were not observed in the fed state. No significant group effects (OP vs. OR) or group-by-sex interactions were observed in fasted or fed states.

CONCLUSIONS

Greater fasted responses to hedonic food cues in reward-related brain regions were observed in women compared with men, suggesting that women may be more sensitive to the reward value of hedonic foods than men when fasted. This may indicate sex-dependent neurophysiology underlying eating behaviors.