which of the following, if true, would most undermine the central premise of jacobs' hypothesis? lsd does not cause as much long-term neurological damage as previously thought. serotonin and norepinephrine are found to rise and fall in tandem. researchers prove conclusively that the level of norepinephrine in the brain is a significant factor in enabling the brain to sleep. some semi-synthetic hallucinogenic drugs other than lsd do not inhibit serotonin. the first three stages of sleep are as crucial to the process of dreaming as the fourth stage.