How the Brain Senses Infection

Researchers discovered specific airway neurons in mice that alert the brain about the flu

A sick person blowing their nose on a couch
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A new study led by researchers at Harvard Medical School illuminates how the brain becomes aware that there is an infection in the body.

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Studying mice, the team discovered that a small group of neurons in the airway plays a pivotal role in alerting the brain about a flu infection. They also found signs of a second pathway from the lungs to the brain that becomes active later in the infection.

The study was published March 8 in Nature.

Although most people are sick several times a year, scientific knowledge of how the brain evokes the feeling of sickness has lagged behind research on other bodily states such as hunger and thirst. The paper represents a key first step in understanding the brain-body connection during an infection.