I don’t know why this is a surprise. At least if you drink enough to get drunk, the function of the brain is temporarily affected; it would amaze me if it could be true that an affected neuron returns to the exact same level.
I have limited experience with being drunk, a little more experience with weed where I became non-functional (like taking a whiz was a challenge and speaking was somehow difficult) and I sure wondered how much function I lost permanently after such an episode.
Have said the above, perhaps there are drugs that temporarily affect brain cells — interfere with neurotransmitters or simulate them but are not neurotoxic. But I think in vitro, alcohol kills neurons and therefore it is to me a scary thing to imbibe.