More filling? Good Taste? How Flies, Perhaps Humans, Choose their Food

Flies have a discriminating taste. Like the gourmet reading menu, they spend most of their time looking for delicious, calorie-free calories and avoid spicy, potentially toxic foods. But what happens to their brain when they make this food choice? Investigators found an interesting way to find out. They deceived them. 


In a study that could also help shed light on how people choose food, researchers have given hungry fruit flies a choice between a delicious, nutritious quinine-sweet meal and a low-sugar, but not spicy, low-calorie diet. Then, using neuroimaging, they track neural activity in their brain as they make these difficult decisions.

So which one got? Calories instead of more real appreciation?

"It depends on how greedy they are," said Michael Nitabach, professor of molecular biology, genetics, and neuroscience at Yale School of Medicine and lead author of the study. "They are so hungry, they are more likely to tolerate a bitter taste in order to get added calories."

However, the real solution to how flies make these decisions is far more difficult, according to a study published July 5 in the journal Nature Communications.

According to a company of researchers led by Preeti Sareen, a research scientist at Yale, flies transmit sensory information to a part of its brain called a fan-shaped body, where signals are assembled, making what looks like an insect-repellent version. Researchers have found that the patterns of neuronal activity in a fan-shaped body change dramatically when a novel food selection is presented, which dictates a fly's decision on what to eat.

But researchers are moving ahead. And things got to the stranger. They found that they could reverse the changes of the fly by controlling the neurons in the fan-feeding areas of the brain. For example, when they cause a decrease in the activity of neurons involved in indigestion, it has been found that it makes hungry flies prefer low-calorie foods.

"It's one big thing to answer for, not just to make top decisions," Nitabach said.

And that's where the connection is with people's food choices, he said. Neural activity in the brain of flies and the human brain is regulated by the secretion of neuropeptides and the neurotransmitter dopamine, which in humans help control the sense of reward. Changes in this network can change the way the brain responds to different types of food. In other words, neurochemistry can sometimes force food choices that we think we are doing with caution.

"This study provides an analogy to understand how factors such as hunger and the emotional state of the air affect our performance," Nitabach stated.

Sareen, including Li Yan McCurdy, a bachelor student at Yale School of Medicine, last joint author of a paper.

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