Sprinkled like confetti throughout this image are dozens of green, yellow, and red-ringed axons—nerve cell fibers that transmit electrical signals throughout the nervous system. The axons are bundled in a human cranial nerve, shown here in a cross-section view (see illustration below for context). Nerves like this exit the brainstem and project to areas of…

A study looked at the data of 1.6 million COVID-19 patients worldwide. The researchers were trying to understand a phenomenon called “long COVID,” where the patients who clear the infection are left with lingering symptoms or new pain after several months have passed. The researchers have found that about 43 percent of infected patients developed…