Unihemispheric slow-wave sleep

Unihemispheric slow-wave sleep refers to a type of sleep that some animals can experience where one half of their brain goes to sleep while the other half remains awake and alert. This type of sleep is commonly seen in birds and some aquatic mammals like dolphins and seals.

Imagine your bed was split in half, with one side being covered in a cozy blanket and the other being left uncovered. Now imagine that while you sleep, one half of your brain goes to sleep under the cozy blanket while the other half stays awake and alert, keeping watch for any danger.

This is similar to what happens during unihemispheric slow-wave sleep. The half of the brain that is sleeping experiences a type of deep sleep called slow-wave sleep, which is important for restoring and rejuvenating the brain. Meanwhile, the half of the brain that is awake can keep the animal alert to its surroundings and help it avoid predators.

This unique ability to sleep with one half of the brain while the other half remains awake is thought to have evolved as a survival mechanism for certain animals. For example, dolphins and seals need to remain alert to avoid predators while sleeping in the water, so unihemispheric slow-wave sleep allows them to do this without having to fully wake up.

Overall, unihemispheric slow-wave sleep is a fascinating adaptation seen in some animals that allows them to sleep and stay alert at the same time, helping them to survive in their environments.