Arousal is a fundamental part of how our brain keeps us alert, engaged, and responsive to the world around us. It is controlled by networks deep in the brainstem, like the locus coeruleus (LC), which ...

(PhysOrg.com) -- You’ve seen it on television: A doctor shines a bright light into an unconscious patient’s eye to check for brain death. If the pupil constricts, the brain is OK, because in mammals, ...

(Medical Xpress) -- We all know that our pupils contract when our eyes are exposed to increases in the brightness of light. The reason is to both protect the delicate inner workings of our eyes and to ...

For the first time, researchers have been able to observe how the pupils react during sleep over a period of several hours. A look under the eyelids showed them that more happens in the brain during ...

Take a close look at a house cat's eyes and you'll see pupils that look like vertical slits. But a tiger has round pupils — like humans do. And the eyes of other animals, like goats and horses, have ...