Flyers have a keen sense of taste. They are like a chef looking at a menu. They seek out sweet, nutritious calories, and avoid bitter, potentially toxic foods. What happens to their brains as they make these food decisions?
Yale researchers found a fascinating way to find out. They tricked them.
Researchers gave hungry fruit flies the option of sweet, nutritious food with bitter quinine or a sweeter, but less bitter, food that contained fewer calories in a study that may help to illuminate people's food choices. They then used neuroimaging to track neural activity in their brains while they made these difficult choices.
Which is better? Which is better? Calories or better tasting?
It all depends on how hungry they're," Michael Nitabach (professor of cellular and molecular biology and genetics at Yale School of Medicine, senior author of the study) said. "The more hungry they are, the easier it is for them to tolerate bitter taste in order to get more calories."
According to Nature Communications, the July 5th study, the true answer to the question of how fly decisions are made is more complicated.
The research team was led by Preeti Sareen, Yale associate researcher. They found that flies transmit sensory information to a part of their brain called "the fan-shaped body". Here signals are combined, which triggers what amounts to an insect version of an executive choice. Researchers found that the patterns of neuronal activity in fan-shaped bodies change adaptively as new food options are introduced. This is what determines how the fly decides what food to eat.
Researchers went one step further. Things got even more bizarre. They discovered that they could alter the choice of a fly by manipulating the neurons in the brains that feed into their fan-shaped bodies. They found that if they decreased activity in metabolic neurons, it would make hungry flies choose lower-calorie foods.
Nitabach stated, "It's one big feedback loop. Not just top-down decision making."
He said that this is where we find connections to the food choices of humans. Neuropeptides and neurotransmitter Dopamine regulate neural activity in a fly's and human's brains. This neurotransmitter helps to regulate reward sensations in humans. This network can change how the brain responds differently to different kinds of food. Neurochemistry can sometimes influence the food choices we make consciously.
Nitabach stated that the study provided a framework to understand how things like hunger or internal emotional states can influence our behavior.
The paper's co-authors are Li Yan McCurdy (a Yale School of Medicine graduate student) and Sareen.