​​A study made by the University of Berkeley has shown that 90 minutes of nap serve to clear the mind and increase learning ability. This experiment was conducted with 39 adults to test a brain region linked to memory.

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This showed that people who did not enjoy the siesta learned more slowly than if you had a nap. This concluded that sleep is needed to clear short-term memory and make room for new information.
 

The more hours remain awake slower it gets the brain, so spend a sleepless night reduces by almost 40% the ability to perform new activities. In conclusion this reduction of hours of sleep is associated with memory loss and neurodegenerative diseases.