Researchers recently studied why it is that we feel so crummy when we get the flu. We may lose our appetite and feel lethargic and down. But that isn’t the infection causing this; it’s our brain. So what exactly is happening? The study found “a cluster of nerve cells in the back of the throat that detects a virus’ presence and sends signals to the brain, triggering symptoms that respond to the infection.” The study investigated mice to better understand the brain signaling. They found that a “cluster of neurons in the back of the throat that connects the upper airways to the brain” is what sends the signals to our brain and mice that lacked these receptors “didn’t act sick when they got the flu.”