We've already seen some examples of how R(+)-Lipoic Acid can protect nerve cells from free radicals and toxins, even in cases where the racemate - or the S(-)-form alone - cannot. In animal studies,lipoic acid has also been shown to protect rodents from a variety of toxins, from amphetamines ⁴³ to the chemotherapy drug cisplatin ⁴⁴ and excitotoxic amino acids like aspartate. ⁴⁵ Furthermore, lipoic acid improves an animal's chance of survival, and prevents much of the loss of brain function, after a simulated "stroke" (created by blocking off the arteries which supply the animals' nerve cells with oxygen and then letting oxygen flood back in), ⁴⁵ and prevents age-associated reductions in long-term potentiation, the mechanism whereby the brain moves short-term memories into long-term storage. ⁴⁶