Alterations of EEG functional connectivity in resting state obese and overweight patients with binge eating disorder: A preliminary report

Intergenerational transfer of binge eating-like behavior: The additive impact of juvenile stress

Binge eating (BE) is consuming large amounts of food in a short time, while experiencing loss of control over eating behavior. BE can be hereditary, and juvenile stress (JS) may contribute to its onset. We examined the impact of JS on BE-like behavior, in an animal model of intergenerational BE. Twenty-four female Wistar rats received 2-h access to palatable food (PF) three or five times a week (3 TW or 5 TW) for 4 weeks, followed by the open field test (OFT). At postnatal day (PND)27-29, female offspring either underwent JS (O-JSC) or not (O-CC). At PND51-53, offspring's stress levels were assessed behaviorally. At PND70-85, offspring received 2-h access to PF three times a week to assess their BE-like tendency. Hair samples were collected afterwards. Compared to 5 TW, 3 TW had a greater binge size. In the elevated plus maze and dark\light box, in O-JSC, offspring of 3 TW (O-3TW) spent less time in the open arms and lit area compared to O-5TW. O-3TW consumed more PF than O-5TW. O-JSC consumed more than O-CC. O-3TW-JSC had higher hair CORT levels than O-3TW-CC and O-5TW-JSC. This study highlights the interplay between maternal and offspring experiences, allowing for the study of underlying mechanisms.

Neuroimaging studies of resting-state functional magnetic resonance imaging in eating disorders

Eating disorders (EDs), including anorexia nervosa (AN), bulimia nervosa (BN), binge-eating disorder (BED), and pica, are psychobehavioral conditions characterized by abnormal eating behaviors and an excessive preoccupation with weight and body shape. This review examines changes in brain regions and functional connectivity in ED patients over the past decade (2013-2023) using resting-state functional magnetic resonance imaging (rs-fMRI). Key findings highlight alterations in brain networks such as the default mode network (DMN), central executive network (CEN), and emotion regulation network (ERN). In individuals with AN, there is reduced functional connectivity in areas associated with facial information processing and social cognition, alongside increased connectivity in regions linked to sensory stimulation, aesthetic judgment, and social anxiety. Conversely, BED patients show diminished connectivity in the dorsal anterior cingulate cortex within the salience network and increased connectivity in the posterior cingulate cortex and medial prefrontal cortex within the DMN. These findings suggest that rs-fMRI could serve as a valuable biomarker for assessing brain function and predicting treatment outcomes in EDs, paving the way for personalized therapeutic strategies.

A Systematic Review of Electrophysiological Findings in Binge-Purge Eating Disorders: A Window Into Brain Dynamics

Binge-purge eating disorders (BP-ED), such as bulimia nervosa and binge eating disorder, may share some neurobiological features. Electroencephalography (EEG) is a non-invasive measurement modality that may aid in research and diagnosis of BP-ED. We conducted a systematic review of the literature on EEG findings in BP-ED, seeking to summarize and analyze the current evidence, as well as identify shortcomings and gaps to inform new perspectives for future studies. Following PRISMA Statement recommendations, the PubMed, Embase, and Web of Science databases were searched using terms related to “electroencephalography” and “binge-purge” eating disorders. Of 555 articles retrieved, 15 met predefined inclusion criteria and were included for full-text analysis. Eleven studies investigated EEG by means of event-related potentials (ERP) in BP-ED individuals: 7 using eating disorder-related stimuli (i.e., food, body image) and 4 using non-eating disorder-related stimuli (i.e., facial expressions or auditory clicks). These studies found significant differences in the N200, P200, P300, and LPP components in BP-ED participants compared to controls, indicating that this population exhibits impairments in selective attention, attentional allocation/processing, and allocation of motivational or emotion-based attention. Five studies investigated EEG using frequency analysis; reporting significant differences in beta activity in fronto-temporal and occipito-temporo-parietal areas in BP-ED individuals compared to controls, revealing a dysfunctional brain network. However, the small number of studies, the heterogeneity of samples, study paradigms, stimulus types, and the lack of an adequate assessment of neuropsychological parameters are some limitations of the current literature. Although some EEG data are promising and consistent with neuroimaging and neuropsychological findings in individuals with BP-ED, future studies need to overcome current methodological shortcomings.

Neuropsychological and Neurophysiological Indicators of General and Food-Specific Impulsivity in Children with Overweight and Obesity: A Pilot Study

Impulsivity, particularly towards food, is a potential risk factor for increased energy intake and the development and maintenance of obesity in children. However, neuropsychological and neurophysiological indicators of general and food-specific impulsivity and their association with children's weight status are poorly understood. This pilot study examined electroencephalography (EEG) frequency band profiles during eyes-closed and eyes-open resting state in n = 12 children with overweight or obesity versus n = 22 normal-weight controls and their link to child- and parent-reported and experimentally assessed impulsivity of children (e.g., risk-taking behavior, approach-avoidance behavior towards food). The main results indicated that children with overweight/obesity versus normal weight showed significantly increased delta and decreased alpha band activity during eyes-closed resting state. Across the total sample, EEG slow-wave band activity was particularly linked to self- and parent-reported impulsivity and greater risk-taking behavior, but not to approach behavior towards food, after controlling for children's age and weight status. The identification of specific EEG patterns in children with excess weight may provide a new basis for developing neurophysiological diagnostic and treatment approaches for childhood obesity. Future studies with larger samples and longitudinal designs are needed to replicate the present findings and test their stability over time.

Abnormal of inter-hemispheric functional connectivity in elderly subjects with overweight/obesity

BACKGROUND

There is a growing literature documenting a variety of brain abnormalities associated with obesity. However, little is known about the effects of obesity on inter-hemispheric connectivity in aging people.

METHODS

Participants included 61 cognitively intact elderly (including people with obesity, overweight, and lean controls) who underwent structural MRI, resting-state functional magnetic resonance imaging (rsfMRI) and standard neuropsychological batteries. Techniques including FreeSurfer and Voxel-mirrored Homotopic Connectivity (VMHC) were employed to evaluate inter-hemispheric structural and functional connectivity respectively.

RESULTS

There were no differences of cognitive abilities and vascular risks among groups. When compared to lean controls, obese group had greater VMHC in fusiform gyrus (FG); while overweight group had greater VMHC in FG, calcarine gyrus, inferior temporal gyrus (ITG), and postcentral gyrus (PCG). Moreover, the obesity group had lower VMHC in calcarine gyrus and PCG than overweight group (p<0.05, corrected).

CONCLUSIONS

The present study suggested, increased inter-hemispheric information transmission in networks supporting visual and sensorimotor function may lead to gain in weight, by possibly mediating diet behaviours of individuals.

Neurobiological evidence for attention bias to food, emotional dysregulation, disinhibition and deficient somatosensory awareness in obesity with binge eating disorder

OBJECTIVES

To refine the biobehavioral markers of binge eating disorder (BED).

METHODS

We conducted fMRI brain scans using images of high energy processed food (HEPF), low energy unprocessed food (LEUF), or non-foods (NF) in 42 adults (obese with BED [obese -BED; n=13] and obese with no BED [obese non-BED; n=29]) selected via ads. Two blood oxygenated level dependent (BOLD) signal contrast maps were examined: food versus nonfood, and HEPF versus LEUF. In addition, score differences on the disinhibition scale were correlated with BOLD signals.

RESULTS

food versus nonfood showed greater BOLD activity for BED in emotional, motivational and somatosensory brain areas: insula, anterior cingulate cortex (ACC), Brodmann areas (BA) 19 & 32, inferior parietal lobule (IPL), posterior cingulate cortex (PCC), and lingual, postcentral, middle temporal and cuneate gyri (p≤0.005; k≥88). HEPF versus LEUF showed greater BOLD activity for BED in inhibitory brain regions: BA 6, middle and superior frontal gyri (p<0.01; k≥119). The groups also differed in the relationships between disinhibition and BOLD activity in the postcentral gyrus (PCG; p=0.04) and ACC-BA 32 (p=0.02). For all participants jointly, PCG BOLD amplitude predicted greater disinhibition (p=0.04).

DISCUSSION

Food images elicited neural activity indicating attention bias (cuneate & PCG), emotion dysregulation (BA 19 & 32), and disinhibition (MFG, BA6 & SFG) in obese with BED. These may help tailor a treatment for the obesity with BED phenotype.

Relation of insulin resistance to neurocognitive function and electroencephalography in obese children

BACKGROUND

Childhood obesity may lead to neuronal impairment in both the peripheral and the central nervous system. This study aimed to investigate the impact of obesity and insulin resistance (IR) on the central nervous system and neurocognitive functions in children.

METHODS

Seventy-three obese children (38 male and 35 female) and 42 healthy children (21 male and 21 female) were recruited. Standard biochemical indices and IR were evaluated. The Wechsler Intelligence Scale for Children-Revised (WISC-R) and electroencephalography (EEG) were administered to all participants. The obese participants were divided into two groups based on the presence or absence of IR, and the data were compared between the subgroups.

RESULTS

Only verbal scores on the WISC-R in the IR+ group were significantly lower than those of the control and IR- groups. There were no differences between the groups with respect to other parameters of the WISC-R or the EEG. Verbal scores of the WISC-R were negatively correlated with obesity duration and homeostatic model assessment-insulin resistance (HOMA-IR) values. EEGs showed significantly more frequent 'slowing during hyperventilation' (SDHs) in obese children than non-obese children.

CONCLUSIONS

Neurocognitive functions, particularly verbal abilities, were impaired in obese children with IR. An early examination of cognitive functions may help identify and correct such abnormalities in obese children.

A Potential Animal Model of Maladaptive Palatable Food Consumption Followed by Delayed Discomfort

Introduction: Binging is the consumption of larger amounts of food in a briefer period of time than would normally be consumed under similar circumstances. Binging requires palatable food (PF) to trigger abnormal eating, probably reflecting gene × environment interactions. In this study we examined the impact of trait binge eating (BE) and its compulsive nature on the conflict between hedonic eating of PF and anticipation of a delayed aversive effect. We used female rats as an animal model similar to other models of BE. A novel aspect of this model in this paper is the use of a delayed internal aversive effect produced by lactose ingestion. Establishing this model will allow us to better understand the nature of the conflict between immediate reward and its delayed aversive implications. We hypothesized that BE prone (BEP) rats will demonstrate maladaptive decision making, presenting higher motivation toward PF even when this is associated with delayed discomfort. Method: (Phase 1) 52 female adult Wistar rats were divided to two eating profiles: resistant and prone binge eaters (BER/BEP) based on intake of liquid PF (Ensure). Next, all subjects underwent a Lactose Conditioning Protocol (LCP) that included 4 h tests, one baseline and 3 conditioning days (Phase 2), in which solid PF (Oreo cookies) was paired with glucose (control-no internal aversive effect) or lactose, dissolved in liquid PF. Index for PF motivation was PF consumption during the 4 h LCP. To test for memory of lactose conditioning, we performed another LCP with glucose only (anticipation, but no actual lactose-induced discomfort), a week after the last conditioning session. Results: Lactose conditioned BEP showed higher motivation toward PF compared to lactose conditioned BER faced with delayed aversive effects. Only lactose conditioned BER rats devaluated the PF over LCP days, indicating an association between PF and abdominal discomfort. In addition, only lactose conditioned BER presented an adaptive dynamic behavior, by varying PF intake according to consequences. Furthermore, solid PF consumption was predicted by binge size of liquid PF, only for lactose conditioned rats. Conclusions: We established an animal model for a common eating conflict in humans using delayed internal aversive unconditional stimuli.