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New research suggests that a hormone produced in the gut, which stimulates hunger, can affect a specific brain region involved in decision-making, leading to changes in an animal’s behavior.
This research is groundbreaking in demonstrating the direct influence of hunger hormones on the hippocampus, a vital area of the brain responsible for decision-making and memory formation, specifically when an animal is contemplating food.
The hippocampus acts as a regulator, preventing animals from overeating by suppressing their natural urge to eat when presented with food.
The UCL researchers propose that if the animal is experiencing hunger, hormones will signal the brain to disable the brakes.
Their discoveries may aid in further investigation of the causes of eating disorders, as well as in understanding other connections between diet and various health consequences, including the potential for mental illnesses.
The main researcher, Dr. Andrew MacAskill from UCL’s departments of neuroscience, physiology, and pharmacology, stated that our choices are often heavily impacted by our level of hunger. This is because food holds a varying significance to us depending on whether we are experiencing hunger or fullness.
Consider how much more you may purchase when grocery shopping while hungry.
However, understanding this seemingly straightforward idea is actually quite complex, as it involves the skill of utilizing contextual learning.
We discovered that a specific area of the brain, which plays a vital role in decision-making, is unexpectedly affected by the amounts of hunger hormones released in our digestive system. We believe this is aiding our brains in understanding the reasons behind our food choices.
During the experiment, mice were situated in an enclosed space with access to food. The scientists observed the mice’s behavior and brain activity using real-time imaging, while noting their hunger levels.
The research determined that while all the mice showed interest in the food, only the ones who were hungry actually started eating.
The scientists were studying the brain’s function in the ventral hippocampus (located beneath the hippocampus).
When the mice encountered food, there was a rise in brain cell activity in a specific group within the ventral hippocampus. This activity inhibited the animal from consuming the food.
However, if the mouse was experiencing hunger, there was a decrease in activity in this region. As a result, the hippocampus did not inhibit the animal’s food intake.
Researchers discovered that individuals with elevated levels of the hunger hormone ghrelin in their bloodstream experienced this phenomenon.
The researchers successfully manipulated mice to exhibit satiety, causing the animals to cease eating even when they were experiencing hunger.
Previous research has demonstrated that animals, including non-human primates, possess ghrelin receptors in their hippocampus. However, there was limited evidence on the functioning of these receptors.
This discovery shows that the hormone responsible for hunger can bypass the blood-brain barrier, which typically blocks many substances from entering the brain. This hormone can then directly affect the brain, leading to increased activity and controlling a circuit that is likely shared with humans.
According to the initial author, Dr. Ryan Wee, from the UCL Department of Neuroscience, Physiology, and Pharmacology, the ability to make decisions based on our level of hunger is crucial.
Failing to address this issue could result in severe health complications.
By enhancing our knowledge of the brain’s processes, we aspire to contribute to the prevention and treatment of eating disorders.
The research has been published in the Neuron journal.