The brain is as active during REM (rapid eye movement) sleep-when most vivid dreams occur-as it is when fully awake, says Dr, Eric Nofzinger at the University of Pittsburgh.

• 匹兹堡大学的埃里克博士说，在出现清晰梦境的快速动眼睡眠中大脑和完全清醒时一样活跃。