A Hunger Hormone and Decision-Making: How Our Brain Controls Our Eating Habits
Have you ever wondered why you make certain food choices when you’re hungry? A recent study conducted by researchers at UCL (University College London) has shed light on the fascinating connection between hunger hormones and decision-making in the brain.
The Impact of Hunger Hormones on the Brain
Published in the journal Neuron, this groundbreaking study in mice is the first of its kind to reveal how hunger hormones directly influence the activity of the brain’s hippocampus, a crucial region involved in decision-making, especially when it comes to food.
Dr. Andrew MacAskill, the lead author of the study from UCL Neuroscience, Physiology & Pharmacology, explains, “We all know our decisions can be deeply influenced by our hunger, as food has a different meaning depending on whether we are hungry or full. Just think of how much you might buy when grocery shopping on an empty stomach. But what may seem like a simple concept is actually very complicated in reality; it requires the ability to use what’s called ‘contextual learning’.”
Contextual Learning and the Brain
Contextual learning refers to the brain’s ability to understand and interpret the significance of food choices based on hunger levels. The researchers discovered that the ventral hippocampus, a part of the brain responsible for decision-making, is surprisingly sensitive to hunger hormones produced in the gut. This sensitivity helps our brains contextualize our eating choices.
Unveiling the Role of the Ventral Hippocampus
To investigate the impact of hunger on brain activity, the researchers conducted experiments with mice. They placed the mice in an arena with food and observed their behavior while imaging their brains in real-time.
Interestingly, all the mice spent time investigating the food, but only the hungry ones started eating. The scientists focused on the ventral hippocampus, specifically studying the activity of a subset of brain cells in this region.
They found that when the mice approached food, the activity in these brain cells increased, inhibiting the animals from eating. However, when the mice were hungry, there was less neural activity in this area, allowing the hippocampus to no longer prevent the animals from eating. This decrease in activity corresponded to high levels of the hunger hormone ghrelin circulating in the blood.
Experimental Manipulation of Hunger Hormones
To further understand the role of ghrelin receptors in the ventral hippocampus, the researchers conducted additional experiments. They were able to make mice behave as if they were full by activating these neurons, causing the animals to stop eating even when hungry. Conversely, by removing the receptors for ghrelin from these neurons, the scientists observed the opposite effect.
Previous studies had shown that animals, including non-human primates, have ghrelin receptors in the hippocampus. However, this study provides valuable insights into how these receptors function. It demonstrates that ghrelin, the hunger hormone, can cross the blood-brain barrier and directly impact the brain, controlling a circuit that is likely to be similar in humans.
Implications for Eating Disorders and Mental Health
The researchers believe that their findings could contribute to research on eating disorders. By investigating the involvement of ghrelin receptors in the hippocampus, they hope to gain a better understanding of the mechanisms behind these disorders and potentially develop new prevention and treatment strategies.
Additionally, the study opens up possibilities for exploring the connections between hunger and other cognitive functions. The researchers plan to investigate whether hunger can affect learning and memory, as well as its potential impact on stress and thirst.
Conclusion
This study highlights the intricate relationship between hunger hormones and decision-making in the brain. By unraveling the role of the ventral hippocampus and its sensitivity to hunger hormones, researchers are paving the way for a deeper understanding of eating habits and their impact on our overall health and well-being.
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