Neurostimulation to lose weight: this is its scientific basis

Obesity is one of the greatest public health challenges of the twenty-first century. Its prevalence has tripled in many European countries in recent decades, reaching 650 million adults with obesity and 340 million children and adolescents with overweight or obesity according to the WHO.
Conventional treatments to lose weight, such as drugs, diets, even stomach reduction surgery, do not definitively solve the problem. A new technique begins to give interesting results: it allows us to act directly on the brain, ‘stimulate’ it to change habits and thus keep obesity at bay.
Through neuromodulation, and more specifically through a type of non-invasive brain stimulation called transcranial direct current stimulation or tDCS, it is possible to modify the activity of the brain by inducing a very faint electric current by placing electrodes on the scalp. It doesn’t hurt, it’s not invasive, it doesn’t require anesthesia or surgery, and it’s not expensive.
At the UOC’s Cognitive NeuroLab we study the effect of non-invasive brain stimulation in patients with different pathologies, including obesity.
Here’s the procedure:
When the person comes to our lab for a tDCS session, we place between two and eight electrodes on their scalp. The number and position of the electrodes depends on the alteration or pathology that we want to treat.
For 20 minutes, the person is sitting comfortably while through the electrodes a very low intensity electric current is induced, directed to an area of the brain especially related to obesity. After those 20 minutes, remove the electrodes.
The sessions are repeated daily over 5 or 10 days, depending on the treatment.
Brain activity in obesity
In addition to lifestyle changes in Western societies, and genetic variables, there are specific neurocognitive factors. [demostrados] that activate and maintain eating patterns associated with weight gain.
People with obesity have a characteristic neurocognitive pattern that can contribute to the development and maintenance of inadequate eating habits.
Neuroimaging studies show alterations in the brain reward circuitry, including the dorsolateral prefrontal cortex, dlPFC, and in brain areas related to satiety.
Specifically, in people with obesity hyperactivity is observed in the brain areas associated with reward, emotion, memory and sensorimotor processing in the face of food stimuli (e.g. hyperactivity in the amygdala, hippocampus, insula, striatum).
In addition, alterations in brain responses related to the regulation of intake and the satiety response (inadequate response of the hypothalamus) and reduced activity in dlPFC, involved in self-control and impulsivity, have been found.
Location of the hypothalamus and cerebellum in the brain.
Author provided
The hypothalamus is the key brain area in controlling homeostatic vegetative functions, including thirst and hunger.
Neuroimaging studies show that while in people without overweight problems the activation of the hypothalamus decreases during intake, generating a feeling of satiety, in people with obesity the reduction of activity is slower in this area of the brain.
Hypothalamus activity is reduced more slowly in people with obesity while they are eating, so they take longer to feel satiated.
Something similar happens with self-control. In patients with obesity, brain activity in the areas responsible for self-control and impulsivity is reduced by food stimuli (hypoactivity of the left dlPFC and left anterior cingulate cortex).
People with obesity have some cognitive impairments shared with other eating disorders and with addictions to substances or gambling.
It is common to find in obese people difficulties in decision-making and in the inhibition of responses, a high impulsivity and a lower ability to delay gratification or reward, which leads them to overeat and, therefore, to gain weight.
In recent years, the impulsivity and lack of self-control that many overweight people experience is getting a lot of research attention.
Impulsivity is considered one of the strongest predictors of overweight, since self-control is fundamental to be able to follow a proper diet and a program of constant physical activity.
Neuromodulation: a new treatment for obesity
In clinical practice there are important limitations in the pharmacological, nutritional and surgical treatments that exist today for weight loss.
The limitations are related to accessibility, cost, adherence and long-term effectiveness. That is why it is essential to look for new therapeutic approaches, with good adherence, that are capable of changing negative eating habits to achieve weight loss and maintain it in the long term.
Obesity has serious medical consequences, conventional treatments do not work at all and, in addition, we have scientific evidence that in people with obesity there are alterations in brain activity. With all this, interventions based on neuromodulation represent an excellent approach to the treatment of a condition as complex and multifactorial as obesity.
The goal of neuromodulation is to modify altered neurocognitive patterns in obesity, to establish new patterns and new healthy eating habits. Neurostimulation is an innovative and promising treatment for obesity.
How tDCS works on the “obese brain”
Using tDCS it is possible to increase the deficient brain activity in the dorsolateral prefrontal cortex (dlPFC) in people with obesity.
By increasing activity in this area of the brain, self-control over food increases and impulsive intake is reduced. In addition, it is possible to modulate the activity of the hypothalamus, stimulating cortical areas, and the cerebellum, widely connected with it. By acting on these brain areas, it increases the feeling of satiety and reduces appetite.
Today, the research carried out with this technique in the study of eating behavior, and more specifically in obesity, is very scarce, but shows positive results.
Several studies have shown that intervention with tDCS can reduce intake, desire to eat and appetite, and increase feelings of satiety. In addition, with tDCS you can increase self-control in the presence of food and [reducir la ansiedad por comer].
In addition, better benefits are obtained when the application of tDCS is combined with physical activity.
The future of neuromodulation in clinical application
TDCS is a safe and painless technique for which the patient does not need any preparation. The possible side effects are practically non-existent, limiting themselves to a possible redness or burning in the area on which the electrodes have been placed or slight headaches, which disappear shortly after or taking some analgesic.
It is a technique of recent use, so it is only established as a treatment in some pathologies, such as depression or chronic pain. Therefore, it is a pioneering technique in every way, especially in eating disorders, since research in this field is very scarce worldwide.
Elena Muñoz Marrón, Full Professor. Faculty of Health Sciences. Neuropsychology Area. Director of the Cognitive NeuroLab, UOC – Universitat Oberta de Catalunya
This article was originally published on The Conversation. Read the original.

Original source in Spanish