Rough night? Depending on specific tweaks to their genes, some fruit flies have trouble falling asleep, and others can't stay asleep. Getting too little shut-eye hurts their memory.
David M. Phillips/Science Source
Michael Arnott, of Cambridge, Mass., says he used to have trouble staying awake on long drives. Sleep specialists discovered he has obstructive sleep apnea, though not for the most common reasons — he isn't overweight, and doesn't smoke or take sedatives.
M. Scott Brauer for NPR
Giedre (left) and Tal Cohen in March 2013, while Giedre was still healthy. Since then, she's begun having symptoms of Alzheimer's disease. In Giedre's case, the illness is tied to a rare genetic mutation she inherited.
Courtesy of Tal Cohen
In this colorized image of a brain cell from a person with Alzheimer's, the red tangle in the yellow cell body is a toxic tangle of misfolded "tau" proteins, adjacent to the cell's green nucleus.
Thomas Deerinck/NCMIR/Science Source