The sleeping brain
Sleep is vital. We know that our brains remain highly active when we sleep. Lack of sleep have many negative effects, both on our health and mental functions. Sleep is necessary for having a fully functioning brain when we are awake; perhaps because sleep helps to restore the energy consumed by the body and brain throughout the day. Sleep may also enable removal of harmful material that accumulate in the brain when we are awake. Sleep seems to play a crucial role in learning and memory, especially by aiding long-term storage of memories.