脑子即使不做梦， 也不休息，脑子只有死了才休息。身体别的器官需要休息。

http://advancedlifeskills.com/blog/what-is-your-brain-doing-while-you-are-sleeping/

During sleep our brain is, in fact, extraordinarily active. As it turns out, much of that activity helps the brain to learn and remember. Sleeping is involved in the learning and memory process in several important ways.