There's actually very little. The only thing that I could find was one study on rats. It gave rats incremental dosages of mefloquine, which was, I think, eventually up to about 7 times the dose of treatment, so much higher than we would use for prophylaxis. They did some testing on the rats that showed some impairment in their functioning that could have to do with balance and things, which would sort of be brain stem. After they were euthanized and stained, they found some abnormalities in the brain stems. That's really it in terms of definitive studies.
On May 6th, 2019. See this statement in context.