The team found that when they put food directly into the mouse stomach, brain cells called PRLH (for prolactin-releasing hormone) were activated by nutrient signals sent from the GI tract, consistent with conventional thinking and the results of prior studies. Gone.
However, when they allowed the mice to eat food normally, those signals from the intestine did not appear. Instead, PRLH brain cells switched to a new activity pattern that was controlled entirely by signals from the mouth.
“It was a complete surprise that these cells were activated by the sensation of taste,” Li said. “This shows that there are other components of the appetite-control system that we should think about.”
Although it may seem counterintuitive to our brains to eat slowly when we are hungry, the brain is actually processing the taste of food in two different ways at the same time.
One part is saying, “This tastes good, eat more,” and the other part is watching how fast you’re eating and saying, “Slow down or you’ll get sick.”
“The balance between these is how fast you eat,” Knight said.
Li said the activity of PRLH neurons affected how tasty the rats found food.