From my admittedly incomplete knowledge of and readings into the literature, it seems that meth is definitely neurotoxic at very high doses (in humans, probably a dose that would either make you physically feel like you took too much or an outright overdose), and there is evidence that "binge" administration of meth can be neurotoxic, in animals. But I would agree with Bilz0r in that the most disturbing, though indirect (because most of the studies I know of are in living people, so you can't examine the tissue directly), evidence comes from the studies of long-term meth addicts.
That said, I believe that we should take all of Ricaurte and friends' pharmacokinetic and pharmacodynamic models of "equivalent human doses" in other animals with a grain…no, a rock…of salt.