ERP and oscillatory differences in overweight/obese and normal-weight adolescents in response to food stimuli

Self-Regulation in Eating Behaviors: The Role of Executive Function in Response to Food Stimuli

Human nutrition is characterized by both automatic and self-regulated processes. One of the dimensions that may be employed in monitoring eating behaviors is the cognitive control played by the executive functions (EFs). The role of EFs in affecting eating behaviors has been assessed in empirical studies, but further analyses are needed in a current society characterized by a food-abundant environment. Accordingly, this study attempted to evaluate the association between weight status and executive functions in response to food-related stimuli. One hundred and forty-four young adults took part in the study (25.7% in overweight condition). The participants completed a set of computerized cognitive tasks to assess cognitive and motor inhibition and working memory in two different conditions: (i) classic versions of the tasks and (ii) modified versions with food cues. The results indicate that food stimuli may influence executive performance and that there is an association between food cue-related executive functioning, particularly in the domain of motor inhibition, and working memory. These results suggest that self-regulation in nutrition may involve executive control. Although further studies are needed, this work suggests the importance of a multidimensional perspective in the analysis of eating behaviors and the relevance of EFs in monitoring our approach to food stimuli in an environmental context.

The Effect of Accelerated Continuous Theta Burst Stimulation on Weight Loss in Overweight Individuals With Schizophrenia: A Double-Blind, Randomized, Sham-Controlled Clinical Trial

BACKGROUND AND HYPOTHESIS

Obesity is a common comorbidity in individuals with schizophrenia and is associated with poor clinical outcomes. At present, there are limited effective approaches for addressing this issue. We conducted a double-blind, randomized, sham-controlled clinical trial to investigate the efficacy of noninvasive magnetic stimulation techniques in reducing obesity in individuals with schizophrenia.

STUDY DESIGN

Forty overweight individuals with schizophrenia were recruited and randomly assigned to receive either the active or sham intervention. The active group received 50 accelerated continuous theta burst stimulation (cTBS) sessions over the left primary motor area (M1), while the sham group received sham stimulation. The primary outcomes were the change in body weight and body mass index (BMI), and the secondary outcomes were the psychiatric symptoms, eating behavior scales, metabolic measures, and electrophysiological to food picture stimuli.

STUDY RESULTS

The study demonstrated a significant decrease in body weight and BMI after the intervention selectively in the active group (mean = -1.33 kg, P = .002), and this improvement remained at the 1-month follow-up (mean = -2.02 kg, P = .008). The score on the Barratt Impulsivity Scale (mean = -1.78, P = 0.036) decreased in the active group and mediated the effect of accelerated cTBS on body weight. In the food picture cue electroencephalograph task, the late positive potential component, which is related to motivated attention and emotional processing, decreased in frontal brain regions and increased in posterior regions after the active intervention.

CONCLUSIONS

The accelerated cTBS may offer a promising approach for treating obesity in individuals with schizophrenia. Further research with a larger sample size or individualized stimulation protocol should be promising.

TRIAL REGISTRATION

Clinical trial registered with clinicaltrials.gov (NCT05086133).

Neural mechanisms of expert persuasion on willingness to pay for sugar

Introduction: Sugar consumption is associated with many negative health consequences. It is, therefore, important to understand what can effectively influence individuals to consume less sugar. We recently showed that a healthy eating call by a health expert can significantly decrease the willingness to pay (WTP) for sugar-containing food. Here, we investigate which aspects of neural responses to the same healthy eating call can predict the efficacy of expert persuasion.

Methods: Forty-five healthy participants performed two blocks of a bidding task, in which they had to bid on sugar-containing, sugar-free and non-edible products, while their electroencephalography (EEG) was recorded. In between the two blocks, they listened to a healthy eating call by a nutritionist emphasizing the risks of sugar consumption.

Results: We found that after listening to the healthy eating call, participants significantly decreased their WTP for sugar-containing products. Moreover, a higher intersubject correlation of EEG (a measure of engagement) during listening to the healthy eating call resulted in a larger decrease in WTP for sugar-containing food. Whether or not a participant’s valuation of a product was highly influenced by the healthy eating call could also be predicted by spatiotemporal patterns of EEG responses to the healthy eating call, using a machine learning classification model. Finally, the healthy eating call increased the amplitude of the P300 component of the visual event-related potential in response to sugar-containing food.

Disussion: Overall, our results shed light on the neural basis of expert persuasion and demonstrate that EEG is a powerful tool to design and assess health-related advertisements before they are released to the public.

Food-related reward sensitivity across the spectrum of body weight and impulsive eating: Pilot findings from a multi-method approach

Overweight with and without comorbid binge-eating disorder (BED) has been associated with increased reward sensitivity, though evidence is heterogeneous. To disentangle this heterogeneity and gain insights into mechanisms of impaired reward processing, this study applied multi-method neuro-behavioural techniques. Reward sensitivity was investigated in N = 49 participants allocated to three subgroups: overweight individuals with BED (BED+, n = 17), overweight individuals without BED (BED-, n = 15), and normal-weight controls (NWC, n = 17). Applying a free exploration paradigm (food vs. non-food stimuli), eye tracking and electroencephalographic data were gathered. A valid cue before stimulus onset indicated the position of food, and the end points analysed after the cue and stimulus onset were attentional approach, attention allocation, and conflict processing (e.g., conflict between looking at the potentially rewarding food stimulus or not). The effect of negative mood was tested using mood induction. The study's main hypothesis was that individuals with overweight, particularly under negative mood, would have increased food-related reward sensitivity. All participants showed increased food-specific attentional approach (p < .001). BED + allocated more attention to food stimuli than non-food stimuli compared to the healthy control (p = .045). For individuals with overweight but without BED (BED-), results indicate that conflict processing might be prolonged after the stimulus onset (p = .011). No group-specific effect of negative mood was found. Preliminary results in overweight individuals with and without comorbid BED suggest that food stimuli are generally rewarding stimuli, but even more so for participants with binge eating psychopathology. Prolonged conflict processing during the confrontation with competing food and non-food stimuli was solely found in the BED- sample and might indicate a compensation mechanism. Replication is warranted. The multi-method approach seems to be promising to give indications for the development of psychotherapeutic treatment.

Preventable risk factors for type 2 diabetes can be detected using noninvasive spontaneous electroretinogram signals

Given the ever-increasing prevalence of type 2 diabetes and obesity, the pressure on global healthcare is expected to be colossal, especially in terms of blindness. Electroretinogram (ERG) has long been perceived as a first-use technique for diagnosing eye diseases, and some studies suggested its use for preventable risk factors of type 2 diabetes and thereby diabetic retinopathy (DR). Here, we show that in a non-evoked mode, ERG signals contain spontaneous oscillations that predict disease cases in rodent models of obesity and in people with overweight, obesity, and metabolic syndrome but not yet diabetes, using one single random forest-based model. Classification performance was both internally and externally validated, and correlation analysis showed that the spontaneous oscillations of the non-evoked ERG are altered before oscillatory potentials, which are the current gold-standard for early DR. Principal component and discriminant analysis suggested that the slow frequency (0.4-0.7 Hz) components are the main discriminators for our predictive model. In addition, we established that the optimal conditions to record these informative signals, are 5-minute duration recordings under daylight conditions, using any ERG sensors, including ones working with portative, non-mydriatic devices. Our study provides an early warning system with promising applications for prevention, monitoring and even the development of new therapies against type 2 diabetes.

Capsaicin-induced pain increases neural responses to low-calorie non-spicy food cues: An ERP study

Capsaicin, the main spicy ingredient in chili, can activate pain receptors on the human tongue and skin. Although some studies have determined that pain influenced preference for high-calorie foods, little is known whether pain can modulate the individuals' preference for spicy foods and its neural mechanisms. After 30 participants underwent painful (topical capsaicin cream) and control (hand cream) treatments, an event-related potential (ERP) study was conducted to investigate the modulation of capsaicin-induced pain on food preference with food images. Results showed that both P3 and late positive potential (LPP) amplitudes during the painful treatment were significantly larger than those during the control treatment for low-calorie non-spicy food cues. However, for the other three categories of food cues, there were no significant differences between the two treatments. The present study suggests that capsaicin-induced pain increases individuals' neural processing of low-calorie non-spicy food cues, which provides empirical evidence on the relationship between pain and neural responses to food cues to help optimize dietary interventions for patients experiencing pain.

“Sound” Decisions: The Combined Role of Ambient Noise and Cognitive Regulation on the Neurophysiology of Food Cravings

Our ability to evaluate long-term goals over immediate rewards is manifested in the brain’s decision circuit. Simplistically, it can be divided into a fast, impulsive, reward “system 1” and a slow, deliberate, control “system 2.” In a noisy eating environment, our cognitive resources may get depleted, potentially leading to cognitive overload, emotional arousal, and consequently more rash decisions, such as unhealthy food choices. Here, we investigated the combined impact of cognitive regulation and ambient noise on food cravings through neurophysiological activity. Thirty-seven participants were recruited for an adapted version of the Regulation of Craving (ROC) task. All participants underwent two sessions of the ROC task; once with soft ambient restaurant noise (∼50 dB) and once with loud ambient restaurant noise (∼70 dB), while data from electroencephalography (EEG), electrodermal activity (EDA), and self-reported craving were collected for all palatable food images presented in the task. The results indicated that thinking about future (“later”) consequences vs. immediate (“now”) sensations associated with the food decreased cravings, which were mediated by frontal EEG alpha power. Likewise, “later” trials also increased frontal alpha asymmetry (FAA) —an index for emotional motivation. Furthermore, loud (vs. soft) noise increased alpha, beta, and theta activity, but for theta activity, this was solely occurring during “later” trials. Similarly, EDA signal peak probability was also higher during loud noise. Collectively, our findings suggest that the presence of loud ambient noise in conjunction with prospective thinking can lead to the highest emotional arousal and cognitive load as measured by EDA and EEG, respectively, both of which are important in regulating cravings and decisions. Thus, exploring the combined effects of interoceptive regulation and exteroceptive cues on food-related decision-making could be methodologically advantageous in consumer neuroscience and entail theoretical, commercial, and managerial implications.

Effects of the calorie content of visual food stimuli and simulated situations on event-related frontal alpha asymmetry and event-related potentials in the context of food choices

Approach and avoidance tendencies play an important role in everyday food choices when choosing between high-caloric, rather unhealthy, and low-caloric, rather healthy options. On a neuronal level, approach and avoidance motivation have been associated with asymmetrical activity of the frontal cortex, often quantified by alpha power averaged over several seconds of resting electroencephalogram (EEG). Going beyond the analysis of resting EEG, the present study aimed to investigate asymmetrical frontal activity in direct response to food stimuli in an event-related design and in combination with event-related potentials (ERPs). Therefore, a sample of 56 young and healthy participants completed a food choice task. They were asked to choose from a selection of high-caloric and low-caloric foods which they would want to eat on a normal day (baseline), when being on a diet, and in a reward situation. On the behavioural level, there was a clear preference for low-caloric foods. Well in line with that, time-frequency analyses of alpha asymmetry revealed relatively stronger temporary (950-1175 ms) left-hemispheric frontal activity, that is, a stronger approach tendency, in response to low-caloric as compared to high-caloric foods. Furthermore, larger P300 for low-caloric foods indicated an increased task relevance of low-caloric foods in the baseline and the reward situation. In contrast, the late positive potential (LPP), an index of subjective value, was larger for high-as compared to low-caloric foods, reflecting the intrinsic rewarding properties of high-caloric foods. ERPs, but not frontal alpha asymmetry, were influenced by the situational context.

A Pilot Event-Related Potentials Study on Mechanisms Underlying a tDCS-Enhanced Food-Specific Response Inhibition Task for Patients With Binge Eating Disorder

Behavioural studies demonstrate alterations in cognitive functioning, particularly impaired response inhibition and increased attentional bias towards food in binge eating disorder (BED). This pilot study aimed to investigate the neurophysiological processing of a food-specific inhibition training combined with anodal transcranial direct current stimulation (tDCS) of the right dorsolateral prefrontal cortex (DLPFC) in 16 patients with BED (mean age = 38.6, mean BMI = 33.7 kg/m²). Patients performed a food-specific antisaccade task at baseline (T0) and in a cross-over design with verum vs. sham stimulation at T1 and T2. We investigated (i) event-related potentials (ERPs; N2, ERN and P3 amplitudes) while executing the task at baseline, (ii) whether baseline ERPs would predict task performance at T1 and T2 and (iii) associations between ERPs, eating disorder pathology and impulsivity at baseline. The mean amplitude of N2 was less pronounced in erroneous saccades (ES) than correct saccades (CS), whereas ERN and P3 mean amplitudes were more pronounced in ES. Moreover, the P3 mean amplitude of ES predicted the percentage of ES at both follow up-measurements irrespective of the applied stimulation (sham vs. verum). N2 in trials with correct saccades were negatively correlated with nonplanning trait impulsivity, while P3 in erroneous antisaccade trials was negatively correlated with food-related impulsivity. Overall, the findings of reduced ERN, enhanced P3 and N2 amplitude might be interpreted as difficulties in response inhibition towards food in individuals with BED. In particular, P3 predicts task outcome at follow-up and might represent a potential marker for inhibitory control processes.

Social reward from giving food to others affects food craving and brain potentials: An imagery-based event-related potential study

The interactions between social and eating behaviors can be quite pronounced and are mediated by overlapping neural circuits. The present event-related potential study tested whether the imagery of a specific prosocial behavior (giving chocolates to grateful children) can influence food cue reactivity. A total of 92 females (mean age = 23.5 years) were randomly assigned to one of three guided imagery conditions. The participants listened to an audio recording and were instructed to imagine one of three possible scenes; giving 30 M&Ms to children, eating 30 M&Ms, or sorting 30 marbles. Directly after the imagery task, the participants were presented with images of M&Ms and marbles while their electroencephalogram was recorded. We examined the Late Positive Potential (LPP) across a fronto-central and a parieto-occipital cluster, M&M craving, and subsequent consumption of (real) M&Ms. The mental imagery of offering M&Ms to children was associated with lower M&M craving and higher fronto-central LPP amplitudes (300-600 ms after picture onset) compared to the other imagery conditions. The consumption of M&Ms did not differ between the groups. The LPP is sensitive to the implementation of craving regulation strategies. Furthermore, heightened LPPs are reliably observed in response to motivationally significant stimuli, conflict, and social context. Future studies are needed to specify the specific psychological processes that are associated with the observed LPP effect. In conclusion, this study demonstrated that mental imagery of receiving a social reward from giving food to others can change components of food cue reactivity in healthy females.

Visual food cue processing in children with Prader-Willi Syndrome

Hyperphagia and the associated interest in food is a characteristic feature of Prader-Willi syndrome (PWS) that emerges during childhood and remains a life-long concern. This study examined neural responses reflecting food cue salience in children with PWS and typical controls, age 3-12 years. Visual event-related potentials were recorded while participants in satiated state passively viewed photographs of high- and low-calorie foods, animals, and neutral objects. Contrary to the prediction, children with PWS did not demonstrate greater than typical neural responses to food, suggesting that it is not an exceptionally motivationally salient stimulus in PWS. Caregiver reports of greater hyperphagia were associated with neural responses to low-calorie foods suggesting accelerated and more fine-grained visual stimulus categorization in terms of edibility and caloric content. Overall, the findings align more closely with the altered satiety rather than increased food reward models of hyperphagia in PWS.

Changing the visualization of food to reduce food cue reactivity: An event-related potential study

Visual food cues automatically capture our attention. Moreover, food cue exposure is associated with an increased desire to eat (craving) and food consumption. We attempted to reduce the attentional bias to images depicting a specific food (M&Ms), craving, and consumption through mental imagery in a sample of 98 females (mean age = 23.82 years). The participants either listened to a guided imagery script that described the crushing of M&Ms to reduce the appetitive value of the chocolates, or they envisioned the sorting of M&Ms, or marbles (as control conditions). Afterward, participants were presented with images of M&Ms (not crushed) and marbles while their electroencephalogram, craving ratings, and M&M consumption were measured. The visualization of crushing M&Ms was associated with increased early (P200) and late positivity (P300, early LPP) to M&M pictures, which indicate automatic (P200/P300) and deliberate attention (LPP). M&M sorting increased craving but did not influence M&M consumption. Our findings show that imaginary M&M crushing cannot reduce attention to M&M images and even has the opposite of the intended effect.

A Pictorial Dot Probe Task to Assess Food-Related Attentional Bias in Youth With and Without Obesity: Overview of Indices and Evaluation of Their Reliability

Several versions of the dot probe detection task are frequently used to assess maladaptive attentional processes associated with a broad range of psychopathology and health behavior, including eating behavior and weight. However, there are serious concerns about the reliability of the indices derived from the paradigm as measurement of attentional bias toward or away from salient stimuli. The present paper gives an overview of different attentional bias indices used in psychopathology research and scrutinizes three types of indices (the traditional attentional bias score, the dynamic trial-level base scores, and the probability index) calculated from a pictorial version of the dot probe task to assess food-related attentional biases in children and youngsters with and without obesity. Correlational analyses reveal that dynamic scores (but not the traditional and probability indices) are dependent on general response speed. Reliability estimates are low for the traditional and probability indices. The higher reliability for the dynamic indices is at least partially explained by general response speed. No significant group differences between youth with and without obesity are found, and correlations with weight are also non-significant. Taken together, results cast doubt on the applicability of this specific task for both experimental and individual differences research on food-related attentional biases in youth. However, researchers are encouraged to make and test adaptations to the procedure or computational algorithm in an effort to increase psychometric quality of the task and to report psychometric characteristics of their version of the task for their specific sample.