In addition to vasodilatation and bradycardia , hyperventilation precedes loss of consciousness . The resultant hypocapnia causes cerebral vasoconstriction and peripheral vasodilatation .
除血管舒张、心搏徐缓和强力呼吸会先于昏厥发生,低碳酸血会引起大脑血管收缩和外周血管舒张。
He can 't recite the paragraph , but can do the one that precedes .
他不能背诵这一段,但能背前面的一段。
She always precedes her lectures with a joke .
她在上课之前总是先讲个笑话。
Some say that , with refined experiments , neuroscience could help researchers to identify the physical processes underlying conscious intention and to better understand the brain activity that precedes it .