梦是什么?《辞海》上说:梦是睡眠中出现的一种生理现象。一般认为,睡眠时如大脑皮层某些部位有一定的兴奋活动,外界和体内的弱刺激到达中枢与这些部位发生某些联系时,就可以产生梦。《大不列颠百科全书》上说:梦是入睡后脑中出现的表象活动。不同文化背景的民族,历来对梦的本质的认识与看法各异:爱斯基摩人相信,在睡眠时人的灵魂离开躯体,到一个梦幻世界游历;印第安人则认为,梦 What is a dream? “Cihai” said: Dream is a physiological phenomenon in sleep. Generally believed that some parts of the cerebral cortex during sleep have some excitement, the outside world and the weak stimulation of the body reached the center and some contact with these parts, you can have a dream. The Encyclopedia Britannica says that dreams are visual representations of the brain that fall asleep. People of different cultural backgrounds have always had different understandings and opinions on the essence of dreams: the Eskimos believe that their souls leave their bodies while sleeping, and travel to a dream world. The Indians think that dreams