The effects of repetitive transcranial magnetic stimulation on eating behaviors and body weight in obesity: A randomized controlled study

Repetitive transcranial magnetic stimulation elicits weight loss and improved insulin sensitivity in type 2 diabetic rats

BACKGROUND

Type 2 diabetes (T2D) accounts for the majority of diabetes incidences and remains a widespread global chronic disorder. Apart from early lifestyle changes, intervention options for T2D are mainly pharmaceutical.

METHODS

Repetitive transcranial magnetic stimulation (rTMS) has been approved by the FDA as a therapeutic intervention option for major depressive disorders, with further studies also indicating its role in energy metabolism and appetite. Considering its safe and non-invasive properties, we evaluated the effects of rTMS on systemic metabolism using T2D rats.

RESULTS

We observed that rTMS improved glucose tolerance and insulin sensitivity in T2D rats after a 10-day exposure. Improved systemic insulin sensitivity was maintained after a 21-day treatment period, accompanied by modest yet significant weight loss. Circulating serum lipid levels, including those of cholesteryl ester, tryglyceride and ceramides, were also reduced following rTMS application. RNA-seq analyses further revealed a changed expression profile of hepatic genes that are related to sterol production and fatty acid metabolism. Altered expression of hypothalamic genes that are related to appetite regulation, neural activity and ether lipid metabolism were also implicated.

CONCLUSION

In summary, our data report a positive impact of rTMS on systemic insulin sensitivity and weight management of T2D rats. The underlying mechanisms via which rTMS regulates systemic metabolic parameters partially involve lipid utilization in the periphery as well as central regulation of energy intake and lipid metabolism.

Repetitive Transcranial Magnetic Stimulation (rTMS) Improves Cognitive Impairment and Intestinal Microecological Dysfunction Induced by High-Fat Diet in Rats

Consuming a high-fat diet (HFD) is widely recognized to cause obesity and result in chronic brain inflammation that impairs cognitive function. Repetitive transcranial magnetic stimulation (rTMS) has shown effectiveness in both weight loss and cognitive improvement, although the exact mechanism is still unknown. Our study examined the effects of rTMS on the brain and intestinal microecological dysfunction. rTMS successfully reduced cognitive decline caused by an HFD in behavioral assessments involving the Y maze and novel object recognition. This was accompanied by an increase in the number of new neurons and the transcription level of genes related to synaptic plasticity (spindlin 1, synaptophysin, and postsynaptic protein-95) in the hippocampus. It was reached that rTMS decreased the release of high mobility group box 1, activation of microglia, and inflammation in the brains of HFD rats. rTMS also reduced hypothalamic hypocretin levels and improved peripheral blood lipid metabolism. In addition, rTMS recovered the HFD-induced gut microbiome imbalances, metabolic disorders, and, in particular, reduced levels of the microvirus. Our research emphasized that rTMS enhanced cognitive abilities, resulting in positive impacts on brain inflammation, neurodegeneration, and the microbiota in the gut, indicating the potential connection between the brain and gut, proposing that rTMS could be a new approach to addressing cognitive deficits linked to obesity.

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).

The effect of continuous theta burst stimulation on antipsychotic-induced weight gain in first-episode drug-naive individuals with schizophrenia: a double-blind, randomized, sham-controlled feasibility trial

Antipsychotic intake may induce weight gain in drug-naive individuals with schizophrenia, leading to poor compliance in clinical management. However, there is still a lack of effective approaches to treat or prevent this side-effect. Therefore, we conducted this pilot study to investigate the effect of continuous theta burst stimulation (cTBS), a non-invasive magnetic stimulation technique, on preventing olanzapine-induced weight gain. Thirty-nine first-episode drug-naive individuals with schizophrenia were randomly assigned to receive either the active or sham cTBS intervention for 25 sessions (5 times per day for 5 consecutive days). The primary outcomes were changes in body weight and body mass index (BMI). Secondary outcomes included psychiatric symptoms, eating behavior scales, behavior tasks, and metabolic measures. For the result, the body weight and BMI increased significantly in the sham group but not in the active group, with a significant group effect. The active group exhibited a selective increase in the cognitive restraint domain in the Three-Factor Eating Questionnaire (TFEQ-CR) and a decrease in stop-signal reaction time compared to the sham group. The effect of cTBS on body weight was mediated by TFEQ-CR. Our findings demonstrated the feasibility that cTBS intervention could be a potential method for preventing olanzapine-induced weight gain in drug-naive first-episode schizophrenia patients through enhancing cognitive restraint to food. Trial registration: clinical trial registered with clinicaltrials.gov (NCT05086133).

The use of non-invasive brain stimulation techniques to reduce body weight and food cravings: A systematic review and meta-analysis

Several studies demonstrated non-invasive brain stimulation (NIBS) techniques such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are safe and simple techniques that can reduce body weight, food cravings, and food consumption in patients with obesity. However, a systematic to evaluate the efficacy of active NIBS versus sham stimulation in reducing body weight and food cravings in patients with obesity is not available. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) using PubMed, Embase, MEDLINE, and Cochrane Central Register of Control Trial between January 1990 and February 2022. Mean differences (MDs) for continuous outcome variables with 95% confidence intervals (95% CIs) were used to examine the effects of NIBS on body weight and body mass index (BMI), whereas the hedges's g test was used to measure the effects on food craving. Nineteen RCTs involving 571 participants were included in this study. Active neurostimulation (TMS and tDCS) was significantly more likely than sham stimulation to reduce body weight (TMS: -3.29 kg, 95% CI [-5.32, -1.26]; I2  = 48%; p < .001; tDCS: -0.82 kg, 95% CI [-1.01, -0.62]; I2  = 0.0%; p = .00) and BMI (TMS: -0.74, 95% CI [-1.17, -0.31]; I2  = 0% p = .00; tDCS: MD = -0.55, 95% CI [-2.32, 1.21]; I2  = 0% p = .54) as well as food cravings (TMS: g = -0.91, 95% CI [-1.68, -0.14]; I2  = 88 p = .00; tDCS: g = -0.32, 95% CI [-0.62, -0.02]; p = .04). Compared with sham stimulation, our findings indicate that active NIBS can significantly help to reduce body weight and food cravings. Hence, these novel techniques may be used as primary or adjunct tools in treating patients with obesity.

Seasonal pattern and depression outcomes from repetitive transcranial magnetic stimulation

Individuals with major depressive disorder (MDD) may exhibit a seasonal pattern. The impact of a seasonal pattern in depressive symptoms on rTMS outcomes is unexplored. A retrospective analysis was performed on patients with MDD receiving open-label high frequency rTMS to the left dorsolateral prefrontal cortex. Having a seasonal pattern was defined as scoring ≥ 12 on the Personal Inventory for Depression and Seasonal Affective Disorder (PIDS). Primary outcomes included improvement in the Hamilton Depression Rating Scale (HAMD) and remission. Secondary analyses included the use of the self-rated Quick Inventory of Depressive Symptomatology (QIDS) to assess for changes in atypical neurovegetative symptoms. Multiple linear regression, multiple logistic regression, and linear mixed effects analyses were performed. 46 % (58/127) of the sample had a seasonal pattern. Seasonal pattern did not significantly influence improvement in HAMD (PIDS < 12, 7.8, SD 5.9; PIDS ≥ 12, 10.4, SD 4.9 or remission (PIDS < 12, 30 %; PIDS ≥ 12, 34 %). There were equivalent degrees of improvement in atypical neurovegetative symptoms over time as assessed using the QIDS. Depression with seasonal pattern was found to respond to rTMS treatment similarly to depression without seasonal pattern, suggesting that this may be a viable treatment for this group.

Novel Insights into the Physiology of Nutrient Sensing and Gut-Brain Communication in Surgical and Experimental Obesity Therapy

Despite standardized surgical technique and peri-operative care, metabolic outcomes of bariatric surgery are not uniform. Adaptive changes in brain function may play a crucial role in achieving optimal postbariatric weight loss. This review follows the anatomic-physiologic structure of the postbariatric nutrient-gut-brain communication chain through its key stations and provides a concise summary of recent findings in bariatric physiology, with a special focus on the composition of the intestinal milieu, intestinal nutrient sensing, vagal nerve-mediated gastrointestinal satiation signals, circulating hormones and nutrients, as well as descending neural signals from the forebrain. The results of interventional studies using brain or vagal nerve stimulation to induce weight loss are also summarized. Ultimately, suggestions are made for future diagnostic and therapeutic research for the treatment of obesity.

Inhibitory control as a potential treatment target for obesity

OBJECTIVES

Strong reward responsiveness to food and insufficient inhibitory control are thought to be implicated in the development and maintenance of obesity. This narrative review addresses the role of inhibitory control in obesity and weight loss, and in how far inhibitory control is a promising target for weight loss interventions.

METHODS

PubMed, Web of Science, and Google Scholar were searched for papers up to May 2021. 41 papers were included.

RESULTS

Individuals with obesity have poorer food-specific inhibitory control, particularly when hungry, and less concurrent activation of inhibitory brain areas. Moreover, this was strongly predictive of future weight gain. More activation of inhibitory brain areas, on the other hand, was predictive of weight loss: individuals with successful weight loss initially show inhibitory brain activity comparable to that of normal weight individuals. When successful weight maintenance is achieved for at least 1 year, this inhibitory activity is further increased. Interventions targeting inhibitory control in obese individuals have divergent effects. Firstly, food-specific inhibitory control training is particularly effective for people with low inhibitory control and high BMI. Secondly, neuromodulation paradigms are rather heterogeneous: although rTMS to the left dorsolateral prefrontal cortex induced some weight-loss, multiple sessions of tDCS reduced food consumption (desire) and induced weight loss in two thirds of the papers. Thirdly, neurofeedback results in successful upregulation of brain activity and connectivity, but occasionally leads to increased food intake. In conclusion, inhibitory control is implicated in obesity. It can be targeted to promote weight loss although major weight losses have not been achieved.

Effect of Repetitive Transcranial Magnetic Stimulation in Inducing Weight Loss in Patients with Chronic Schizophrenia: A Randomized, Double-Blind Controlled 4-Week Study

OBJECTIVES

There is emerging evidence that high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) may promote weight loss in individuals with obesity in the general population. However, no study has been conducted on patients with schizophrenia (SZ). This study evaluated the efficacy of 10Hz rTMS in reducing body weight in patients with chronic SZ.

METHODS

Forty-seven SZ patients were randomly assigned to two groups: 10Hz rTMS or sham stimulation over DLPFC (applied once daily) for 20 consecutive treatments. Body weight was assessed at baseline, at the end of week 1, week 2, week 3 and week 4. Clinical symptoms were evaluated with the Positive and Negative Syndrome Scale (PANSS) at baseline and at the end of week 4.

RESULTS

We found that compared with patients in the sham group, 10Hz rTMS treatment significantly reduced body weight in patients with chronic SZ after a period of 4 weeks of stimulation. Interestingly, further analysis found that from the first week (5 sessions) of treatment, there was a significant difference in body weight between active and sham groups after controlling for baseline weight. However, active rTMS treatment did not improve the psychotic symptoms compared to sham stimulation.

CONCLUSION

Our results suggest that add-on HF rTMS could be an effective therapeutic strategy for body weight control in patients with chronic SZ.

Reducing craving and consumption in individuals with drug addiction, obesity or overeating through neuromodulation intervention: a systematic review and meta-analysis of its follow-up effects

BACKGROUND AND AIMS

Non-invasive brain stimulation has shown potential in clinical applications aiming at reducing craving and consumption levels in individuals with drug addiction or overeating behaviour. However, it is unclear whether these intervention effects are maintained over time. This study aimed to measure the immediate, short- and long-term effects of excitatory transcranial direct current stimulation (tDCS) and high-frequency repetitive transcranial magnetic stimulation (rTMS) targeting at dorsolateral prefrontal cortex (dlPFC) in people with drug addiction or overeating.

METHODS

A systematic review and random effects meta-analysis. We included 20 articles (total of 22 studies using randomized controlled trials: 3 alcohol dependence, 3 drug dependence, 12 smoking, 4 overeating; total: 720 participants) from January 2000 to June 2020, which reported at least one follow-up assessment of craving, consumption or abstinence levels after the intervention. We compared effects of active versus sham stimulation immediately after the intervention and at the last follow-up assessment, as compared with baseline.

RESULTS

Excitatory neuromodulation of dlPFC activity reduced craving and consumption immediately after the intervention (craving: g = 0.734, CI = 0.447-1.021, P < 0.001; consumption: g = 0.527, CI = 0.309-0.745; P < 0.001), as well as during short-, mid- and long-term abstinence (craving: g = 0.677, CI = 0.440-0.914, P < 0.001; consumption: g = 0.445, CI = 0.245-0.645, P < 0.001; abstinence levels: g = 0.698, CI = 0.433-0.963, P < 0.001; average time of follow-up: 84 ± 83 days after last stimulation). Additional analysis demonstrated that the intervention effects were sustained in all populations studied (food, nicotine, alcohol or drug abuse) and with both stimulation techniques used (rTMS, tDCS). Interventions targeting at the left (vs right) hemisphere may be more effective.

CONCLUSIONS

Excitatory neuromodulation targeting the dorsolateral prefrontal cortex appears to lead to a sustained reduction of craving and consumption in individuals with addiction or overeating behaviour.

How Impulsiveness Influences Obesity: The Mediating Effect of Resting-State Brain Activity in the dlPFC

Impulsiveness is a stable personal characteristic that contributes to obesity and may interact with it. Specifically, obesity is caused by unrestrained impulse eating that is not consciously controlled and leads to a hormonal imbalance that also can impair impulse control. However, the mechanism of this relationship is unclear. In our study, 35 obese individuals (body mass index, BMI > 28) were recruited and matched with 31 healthy controls (BMI < 24) in age and education level. All the participants underwent a resting-state fMRI and completed the Barratt Impulsiveness Scale-11. The results showed that patients with obesity had a significantly lower fractional amplitude of low-frequency fluctuations (fALFF) in the bilateral dorsolateral prefrontal cortex (dlPFC) and higher fALFF in the left fusiform cortex. In addition, non-planning impulsiveness was positively correlated with BMI. Importantly, we found that the right dlPFC completely mediated the relationship between non-planning impulsiveness and BMI. Our findings suggest that impulsivity is statistically more likely to precede obesity than to precede impulsivity and contributes to obesity by downregulating spontaneous activity in the dlPFC. This suggests that the dlPFC, which is associated with executive control, may be able a potential target for treating obesity.

A systematic review on neuromodulation therapies for reducing body weight in patients with obesity

The global prevalence of obesity increases yearly along with a rising demand for efficacious, safe, and accessible treatments. Neuromodulation interventions (i.e., deep brain stimulation [DBS], transcranial magnetic stimulation [TMS], transcranial direct current stimulation [tDCS], percutaneous neurostimulation [PENS], vagus nerve stimulation [VNS], and gastric electrical stimulation [GES]) have been proposed as novel therapies. This systematic review sought to examine the safety and efficacy of neuromodulation therapies in reducing body weight in patients with obesity. Using PRISMA guidelines, we performed a systematic review for studies on neuromodulation for the treatment of obesity, resulting in 60 trials included (7 DBS, 5 TMS, 7 tDCS, 17 PENS and VNS, and 24 GES; a total of 3,042 participants). While promising results have been reported in open label studies, double-blinded randomized clinical trials often did not reach their primary endpoints, with no technique inducing a striking reduction in body weight. Bearing in mind the complexity and multifactorial nature of obesity, it is possible that a single treatment may not be enough for patients to lose or maintain the weight lost at long term.

Increasing Physical Activity among Breast Cancer Survivors by Modulating Temporal Orientation with rTMS: Feasibility and Potential Efficacy

Maintaining adequate amounts of physical activity is a critical component of survivorship care for women with breast cancer. Increased physical activity is associated with increases in well-being, quality of life, and longevity, but women with cancer face unique, cancer-related factors that might affect physical activity. Consistent with the Competing Neurobehavioral Decision Systems model of decision making, we proposed to decrease delay discounting and increase physical activity by stimulating the executive function system via high-frequency repetitive transcranial magnetic stimulation (HF rTMS) of the left dorsolateral prefrontal cortex (LDLPFC). This randomized, sham-controlled, double-blinded trial examined the feasibility and potential efficacy of this approach to increase physical activity in breast cancer survivors. We hypothesized that active rTMS would significantly increase the mean number of steps per day and decrease delay discounting. Participants (n = 30) were primarily middle-aged (M = 53.7, SD = 7.9) and white with a mean BMI and body mass indices below 40. Indicators of feasibility and limited efficacy testing were positive. Although repeated-measures ANOVA revealed no significant changes in delay discounting, generalized estimating equations (GEE) found that participants in the active condition increased their mean daily steps by 400 steps per day, while those in the sham condition decreased this by nearly 600 steps per day. These findings indicate that the continued investigation of HF rTMS for increasing physical activity among women with breast cancer is justified.

Efficacy and acceptability of noninvasive brain stimulation interventions for weight reduction in obesity: a pilot network meta-analysis

BACKGROUND/OBJECTIVES

Obesity has recently been recognized as a neurocognitive disorder involving circuits associated with the reward system and the dorsolateral prefrontal cortex (DLPFC). Noninvasive brain stimulation (NIBS) has been proposed as a strategy for the management of obesity. However, the results have been inconclusive. The aim of the current network meta-analysis (NMA) was to evaluate the efficacy and acceptability of different NIBS modalities for weight reduction in participants with obesity.

METHODS

Randomized controlled trials (RCTs) examining NIBS interventions in patients with obesity were analyzed using the frequentist model of NMA. The coprimary outcome was change in body mass index (BMI) and acceptability, which was calculated using the dropout rate.

RESULTS

Overall, the current NMA, consisting of eight RCTs, revealed that the high-frequency repetitive transcranial magnetic stimulation (TMS) over the left DLPFC was ranked to be associated with the second-largest decrease in BMI and the largest decrease in total energy intake and craving severity, whereas the high-frequency deep TMS over bilateral DLPFC and the insula was ranked to be associated with the largest decrease in BMI.

CONCLUSION

This pilot study provided a "signal" for the design of more methodologically robust and larger RCTs based on the findings of the potentially beneficial effect on weight reduction in participants with obesity by different NIBS interventions.

Repetitive Transcranial Magnetic Stimulation: A Potential Treatment for Obesity in Patients with Schizophrenia

Obesity is highly prevalent in patients with schizophrenia and, in association with metabolic syndrome, contributes to premature deaths of patients due to cardiovascular disease complications. Moreover, pharmacologic, and behavioral interventions have not stemmed the tide of obesity in schizophrenia. Therefore, novel effective interventions are urgently needed. Repetitive transcranial magnetic stimulation (rTMS) has shown efficacy for inducing weight loss in obese non-psychiatric samples but this promising intervention has not been evaluated as a weight loss intervention in patients with schizophrenia. In this narrative review, we describe three brain mechanisms (hypothalamic inflammation, dysregulated mesocorticolimbic reward system, and impaired prefrontal cortex function) implicated in the pathogenesis and pathophysiology of obesity and emphasize how the three mechanisms have also been implicated in the neurobiology of schizophrenia. We then argue that, based on the three overlapping brain mechanisms in obesity and schizophrenia, rTMS would be effective as a weight loss intervention in patients with schizophrenia and comorbid obesity. We end this review by describing how deep TMS, relative to conventional TMS, could potentially result in larger effect size for weight loss. While this review is mainly conceptual and based on an extrapolation of findings from non-schizophrenia samples, our aim is to stimulate research in the use of rTMS for weight loss in patients with schizophrenia.

Repetitive deep TMS for the reduction of body weight: Bimodal effect on the functional brain connectivity in "diabesity"

BACKGROUND AND AIMS

Deep repetitive Transcranial Magnetic Stimulation (deep rTMS) over the bilateral insula and prefrontal cortex (PFC) can promote weight-loss in obesity, preventing cardiometabolic complications as Type 2 Diabetes (T2D). To investigate the changes in the functional brain integration after dTMS, we conducted a resting-state functional connectivity (rsFC) study in obesity.

METHODS AND RESULTS

This preliminary study was designed as a randomized, double-blind, sham-controlled study: 9 participants were treated with high-frequency stimulation (realTMS group), 8 were sham-treated (shamTMS group). Out of the 17 enrolled patients, 6 were affected by T2D. Resting-state fMRI scans were acquired at baseline (T0) and after the 5-week intervention (T1). Body weight was measured at three time points [T0, T1, 1-month follow-up visit (FU1)]. A mixed-model analysis showed a significant group-by-time interaction for body weight (p = .04), with a significant decrease (p < .001) in the realTMS group. The rsFC data revealed a significant increase of degree centrality for the realTMS group in the medial orbitofrontal cortex (mOFC) and a significant decrease in the occipital pole.

CONCLUSION

An increase of whole-brain functional connections of the mOFC, together with the decrease of whole-brain functional connections with the occipital pole, may reflect a brain mechanism behind weight-loss through a diminished reactivity to bottom-up visual-sensory processes in favor of increased reliance on top-down decision-making processes.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT03009695.

Clinical Benefit of Rehabilitation Training in Spinal Cord Injury: A Systematic Review and Meta-Analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

This study was performed to evaluate the effects of different rehabilitation interventions in spinal cord injury.

SUMMARY OF BACKGROUND DATA

Several activity-based interventions have been widely applied in spinal cord injury in the past, but the effects of these rehabilitation exercises are controversial.

METHODS

Publications were searched from databases (PubMed, Embase, Cochrane, the database of the U.S. National Institutes of Health and World Health Organization International Clinical Trials Registry Platform) using the searching terms like spinal cord injury, transcranial magnetic stimulation, functional electrical stimulation, activity-based therapy, and robotic-assisted locomotor training. Randomized controlled trials and controlled trials were included. The primary outcomes included functional upper/lower extremity independence, walking capacity, spasticity, and life quality of individuals with spinal cord injury. Meta-analysis was performed using Revman 5.0 software.

RESULTS

Thirty-one articles were included. Meta-analysis showed that transcranial magnetic stimulation improved walking speed (95% confidence interval [CI] 0.01, 0.16) and lower extremity function (95% CI 1.55, 7.27); functional electrical stimulation significantly increased upper extremity independence (95% CI 0.37, 5.48). Robotic-assisted treadmill training improved lower extremity function (95% CI 3.44, 6.56) compared with related controls.

CONCLUSION

Activity-based intervention like transcranial magnetic stimulation, functional electrical stimulation, and robotic-assisted treadmill training are effective in improving function in individuals with spinal cord injury.Level of Evidence: 1.

Gut Microbiota: From the Forgotten Organ to a Potential Key Player in the Pathology of Alzheimer's Disease

More than 300 years ago, Antony van Leewenhoeck first described observing single-celled microorganisms, which he termed “animalcules,” examining his saliva under a microscope. Although the idea of the coexistence of microorganisms in our body is not new, we have only recently been able to investigate their ecological relationship to our body, with the development of high-throughput molecular techniques. The diverse microorganism communities residing in our guts are established and maintained by complex interactions among microorganisms and their host. Notably, their alteration has been implicated in influencing various diseases including neurological diseases. Alzheimer’s disease (AD) is the most common cause of dementia characterized by a progressive decline in memory and thinking severe enough to interfere with daily life. Despite the great progress in linking genetic risk factors with AD pathogenesis, treatments targeted at AD pathology and its modifiers have not yet resulted in a disease-modifying therapy. There is mounting evidence that the gut microbiota interacts with AD pathogenesis by disrupting neuroinflammation and metabolic homeostasis—the gut microbiota has gone from being the forgotten organ to a potential key player in the AD pathology.

Efficacy of Repetitive Transcranial Magnetic Stimulation (rTMS)in Inducing Weight Loss among Obese Filipino Patients:A Randomized Controlled Trial

OBJECTIVE

To determine the efficacy of rTMS in decreasing body mass index (BMI) versus sham stimulation among obese Filipino patients.

Methodology

This was a single-center, randomized, sham-controlled, single-blind, parallel group trial. Participants were 15-65 years old with BMI ≥30 kg/m² and weight stable for 6 weeks. Participants were randomized to receive real rTMS or sham stimulation. Each underwent 4 sessions of stimulation over 2 weeks. Anthropometrics, total caloric intake (TCI), and VAS score for appetite were taken at baseline, 2, 4, 6, and 12 weeks.

RESULTS

A total of 31 patients were randomized with 15 to the treatment and 14 to sham stimulation completing treatment, with 2 lost to follow-up. A significant decrease in BMI was noted after 4 weeks from the start of rTMS in the treatment group, (0.6±0.6, p-value=0.001), with weight change of -1.3±1.3 kg (p-value=0.009), but was no longer observed at 6 weeks onwards. No severe adverse effects were noted.

Conclusion

rTMS to the DLPFC effectively decreased BMI (0.6±0.6) and weight (-1.3±1.3 kg) from baseline to 4 weeks. At 6-12 weeks after rTMS however, there was no longer a significant difference, indicating that 4 sessions of rTMS may not be enough to produce a prolonged effect on weight loss.

Transcranial Magnetic Stimulation Meets Virtual Reality: The Potential of Integrating Brain Stimulation With a Simulative Technology for Food Addiction

The aim of this perspective is to propose and discuss the integration of transcranial magnetic stimulation (TMS) over the dorsolateral prefrontal cortex with virtual reality (VR) food exposure for therapeutic interventions for food addiction. "Food addiction" is a dysfunctional eating pattern which is typically observed in eating disorders (ED) such as bulimia nervosa and binge eating disorder. Food addiction has been compared to substance use disorder due to the necessity of consuming a substance (food) and the presence of a dependence behavior. In recent years, VR has been applied in the treatment of ED because it triggers psychological and physiological responses through food exposure in place of real stimuli. Virtual reality-Cue exposure therapy has been proven as a valid technique for regulating anxiety and food craving in ED. More, TMS has been proven to modulate circuits and networks implicated in neuropsychiatric disorders and is effective in treating addiction such as nicotine craving and consumption and cocaine use disorder. The combination of a simulative technology and a neurostimulation would presumably provide better improvement compared to a single intervention because it implies the presence of both cognitive and neuropsychological techniques. The possible advantage of this approach will be discussed in the perspective.

Food Addiction: Implications for the Diagnosis and Treatment of Overeating

With the obesity epidemic being largely attributed to overeating, much research has been aimed at understanding the psychological causes of overeating and using this knowledge to develop targeted interventions. Here, we review this literature under a model of food addiction and present evidence according to the fifth edition of the Diagnostic and Statistical Manual (DSM-5) criteria for substance use disorders. We review several innovative treatments related to a food addiction model ranging from cognitive intervention tasks to neuromodulation techniques. We conclude that there is evidence to suggest that, for some individuals, food can induce addictive-type behaviours similar to those seen with other addictive substances. However, with several DSM-5 criteria having limited application to overeating, the term 'food addiction' is likely to apply only in a minority of cases. Nevertheless, research investigating the underlying psychological causes of overeating within the context of food addiction has led to some novel and potentially effective interventions. Understanding the similarities and differences between the addictive characteristics of food and illicit substances should prove fruitful in further developing these interventions.

Health, pleasure, and fullness: changing mindset affects brain responses and portion size selection in adults with overweight and obesity

BACKGROUND

Increased portion size is an essential contributor to the current obesity epidemic. The decision of how much to eat before a meal begins (i.e. pre-meal planning), and the attention assigned to this task, plays a vital role in our portion control.

OBJECTIVE

We investigated whether pre-meal planning can be influenced by a shift in mindset in individuals with overweight and obesity in order to influence portion size selection and brain activity.

DESIGN

We investigated the neural underpinnings of pre-meal planning in 36 adults of different weight groups (BMI < 25 kg/m² and BMI ≥ 25 kg/m²) by means of functional magnetic resonance imaging. To examine the important role of attentional focus, participants were instructed to focus their mindset on the health effects of food, expected pleasure, or their intention to stay full until dinnertime, while choosing their portion size for lunch.

RESULTS

We observed that participants of all weight groups reduced their portion size when adopting a health mindset, which was accompanied by enhanced activation of the self-control network (i.e. left prefrontal cortex). Fullness and pleasure mindsets resulted in contrasting reward responses in individuals with overweight and obesity compared to normal-weight individuals. Under the pleasure mindset, persons with overweight and obesity showed heightened activity in parts of the taste cortex (i.e. right frontal operculum), while the fullness mindset caused reduced activation in the ventral striatum, an important component of the reward system. Moreover, participants with overweight and obesity did not modify their behaviour under the pleasure mindset and selected larger portions than the normal-weight group.

CONCLUSIONS

We were able to identify specific brain response patterns as participants made a final choice of a portion size. The results demonstrate that different brain responses and behaviours during pre-meal planning can inform the development of effective strategies for healthy weight management.

Invasive and Non-invasive Stimulation of the Obese Human Brain

Accumulating evidence suggests that non-invasive and invasive brain stimulation may reduce food craving and calorie consumption rendering these techniques potential treatment options for obesity. Non-invasive transcranial direct current stimulation (tDCS) or repetitive transcranial magnet stimulation (rTMS) are used to modulate activity in superficially located executive control regions, such as the dorsolateral prefrontal cortex (DLPFC). Modulation of the DLPFC’s activity may alter executive functioning and food reward processing in interconnected dopamine-rich regions such as the striatum or orbitofrontal cortex. Modulation of reward processing can also be achieved by invasive deep brain stimulation (DBS) targeting the nucleus accumbens. Another target for DBS is the lateral hypothalamic area potentially leading to improved energy expenditure. To date, available evidence is, however, restricted to few exceptional cases of morbid obesity. The vagal nerve plays a crucial role in signaling the homeostatic demand to the brain. Invasive or non-invasive vagal nerve stimulation (VNS) is thus assumed to reduce appetite, rendering VNS another possible treatment option for obesity. Based on currently available evidence, the U.S. Food and Drug Administration recently approved VNS for the treatment of obesity. This review summarizes scientific evidence regarding these techniques’ efficacy in modulating food craving and calorie intake. It is time for large controlled clinical trials that are necessary to translate currently available research discoveries into patient care.

Neuroimaging, neuromodulation, and population health: the neuroscience of chronic disease prevention

Preventable chronic diseases are the leading cause of death in the majority of countries throughout the world, and this trend will continue for the foreseeable future. The potential to offset the social, economic, and personal burdens associated with such conditions depends on our ability to influence people's thought processes, decisions, and behaviors, all of which can be understood with reference to the brain itself. Within the health neuroscience framework, the brain can be viewed as a predictor, mediator, moderator, or outcome in relation to health-related phenomena. This review explores examples of each of these, with specific reference to the primary prevention (i.e., prevention of initial onset) of chronic diseases. Within the topic of primary prevention, we touch on several cross-cutting themes (persuasive communications, delay discounting of rewards, and self-control), and place a special focus on obesity as a disorder influenced by both eating behavior and exercise habits.

Current state of the use of neuroimaging techniques to understand and alter appetite control in humans

PURPOSE OF REVIEW

It is in the brain where the decision is made what and how much to eat. In the last decades neuroimaging research has contributed extensively to new knowledge about appetite control by revealing the underlying brain processes. Interestingly, there is the fast growing idea of using these methods to develop new treatments for obesity and eating disorders. In this review, we summarize the findings of the importance of the use of neuropharmacology and neuroimaging techniques in understanding and modifying appetite control.

RECENT FINDINGS

Appetite control is a complex interplay between homeostatic, hedonic, and cognitive processes. Administration of the neuropeptides insulin and oxytocin curb food intake and alter brain responses in reward and cognitive control areas. Additionally, these areas can be targeted for neuromodulation or neurofeedback to reduce food cravings and increase self-control to alter food intake.

SUMMARY

The recent findings reveal the potential of intranasal administration of hormones or modifying appetite control brain networks to reduce food consumption in volunteers with overweight and obesity or individuals with an eating disorder. Although long-term clinical studies are still needed.