Improving Insulin Sensitivity by Non-invasive Brain Stimulation

Improving Insulin Sensitivity by Non-invasive Brain Stimulation

Efforts in curing and preventing obesity and type 2 diabetes (T2D) have been elusive thus far. One reason for that is the lack of understanding of the role of the brain in the development and treatment of the disease. In recent studies, the hypothalamus was identified as part of a brain network including higher cognitive regions that is particularly vulnerable to insulin resistance. Furthermore, the central insulin response in this network predicted food craving and hunger. In this project, transcranial direct current stimulation (tDCS) is implemented as a tool to stimulate brain networks. The investigators hypothesize that stimulating the hypothalamus-cognitive network will enhance insulin sensitivity and reduce food intake, food craving and hunger. Furthermore, the project will provide the unique opportunity to investigate novel mechanisms of insulin resistance in participants who have been extensively metabolically characterized.

Objectives The overarching aim of the study is to stimulate the hypothalamus-cognitive brain network to improve insulin sensitivity and eating behavior.

Specific Objectives

1. Implement tDCS stimulation compared to sham stimulation in overweight and obese adults to assess the impact on eating behavior, cognition and metabolism.
2. Evaluate whether 3-day non-invasive brain stimulation of the hypothalamus-cognitive network has a causal effect on metabolism.
3. Evaluate whether 3-day non-invasive brain stimulation has a significant effect on brain functional connectivity and diffusion parameters.

Inclusion Criteria:

• Body mass index (BMI) between 25.5 and 39.5 kg/m2
• Age between 20 to 66 years of age
• Waist circumference ≥ 80 cm for women, ≥ 94 cm for men

Exclusion Criteria:

• Insufficient knowledge of the German language
• Persons who cannot legally give consent
• Pregnancy or lactation
• History of severe mental or somatic disorders including neurological diseases (incl. epileptic seizures)
• Taking psychotropic drugs
• Previous bariatric surgery
• Acute infection within the last 4 weeks
• Hemoglobin values less than 12g/dl for women, less than 14 g/dl for men
• Current participation in a lifestyle intervention study or a pharmaceutical study
• Contradictions to a MRI measurement (e.g. metal implants)