source: In 1989, psychiatry professor John Olney reported ketamine caused irreversible changes in two small areas of the rat brain, which, however, has significant differences in metabolism from the human brain, so may not occur in humans.
target: Psychiatry professor John Olney reported ketamine caused irreversible changes in two small areas of the rat brain. He reported this in 1989. However, the rat brain has significant differences in metabolism from the human brain.  So changes may not occur in humans.
references: Psychiatry professor John Olney reported ketamine caused irreversible changes in two small areas of the rat brain. He reported this in 1989. However, the rat brain has significant differences in metabolism from the human brain.  So changes may not occur in humans.