Researchers from the Max Planck Institute for Metabolism Research have discovered that obesity, which is marked by diminished insulin sensitivity, adversely affects the brain’s capacity for associative learning. Intriguingly, a single administration of the anti-obesity medication liraglutide was sufficient to restore this cognitive function, equalizing neural activity between individuals with obesity and those of average weight.
Liraglutide appears to improve cognitive functions in persons afflicted with obesity.
The brain requires the ability to form associations between various stimuli in order to govern behavior effectively. For example, it learns to associate a seemingly innocuous visual signal with a potential consequence, such as the appearance of a red-hot stove surface indicating a burn risk. This cognitive process is essential for understanding the repercussions of interacting with specific stimuli.
Associative learning serves as the foundation for establishing neural pathways and imbuing stimuli with motivational significance. It is primarily regulated by an area of the brain known as the dopaminergic midbrain, which possesses numerous receptors for signaling molecules like insulin, thereby allowing the brain to adapt behavior according to the body’s physiological demands.
The study sought to examine the impact of reduced insulin sensitivity, common in obesity, on brain activity, associative learning, and consequently, behavior. The research involved two groups of volunteers; the first with normal body weight and high insulin sensitivity, and the second with obesity and reduced insulin sensitivity.
Reduced insulin sensitivity impairs the brain’s capability to form associations between sensory stimuli.
Participants were administered either liraglutide or a placebo during the evening. Liraglutide is a GLP-1 agonist, which activates the GLP-1 receptor, thereby inducing insulin production and a sensation of fullness. It is commonly used in the treatment of obesity and type 2 diabetes and is typically administered once daily.
The following morning, the participants undertook a learning task that enabled the researchers to assess the efficacy of associative learning. The findings revealed that individuals with obesity had diminished abilities in forming associations between sensory stimuli and exhibited reduced neural activity in areas responsible for this learning process.
Remarkably, a single dose of liraglutide effectively neutralized these cognitive deficits in participants with obesity, equalizing their brain activity to that of their normal-weight counterparts.
Marc Tittgemeyer, the study’s lead investigator, stated, “These results hold fundamental implications. They indicate that basic behaviors like associative learning are influenced not only by external environmental factors but also by the individual’s metabolic state. The improvements seen in subjects with obesity align with studies demonstrating that these medications restore normal satiety sensations, leading to reduced food intake and weight loss.”
Ruth Hanßen, the study’s first author and a physician at the University Hospital of Cologne, emphasized the urgency of addressing obesity prevention in healthcare systems. She noted, “Although it is promising that existing medications positively impact brain activity in cases of obesity, it is concerning that even young individuals with obesity, devoid of other medical conditions, display altered cognitive performance. Preventing obesity should take precedence over lifelong medication.”
The study received support from the CECAD Cluster of Excellence for Ageing Research at the University of Cologne and the University Hospital of Cologne.
Reference: “Liraglutide Restores Impaired Associative Learning in Individuals with Obesity” by Ruth Hanssen et
