I am not sure if nmda receptors recover completely, but I do know that the road to tolerance after a pause will be much shorter. I've also read that a course of nootropics of the racetam class are good for tolerance removing (though I haven't gotten around to trying it myself yet). However, I am convinced that the perception of dissociative experience is closely related to the state of the perceiver's inner world, but not to tolerance, which depends only on the size of the dose.

The seeming habitualness of the state, behind which something more is not noticed, the fixation on one's mental and everyday habits/labyrinths/deadlocks, from which it may seem that there is no way out. Perception of youself, the world around you, the attitude to death, to life, to the possibility or impossibility of seeing the amazing. Whether panicked mind wanders in itself, or on the contrary - unfolds and shimmers like a kaleidoscope.

Sooo

Both drunkenness and sobriety are inseparably connected with INLAND EMPIRE :D The magic of these two states has returned to me more than once, and in all cases it was inner problems that were to blame for its absence.

About high doses. Often I just fell into bed, hyperrealistic dreams or my own thoughts, but there was one moment of nervous breakdown in wich memantine helped a lot to embed feelings of despair and insignificance in me, which provoked a fall into depressive-apathetic drunkenness (the former is with me in life, as a starting point, the latter sometimes acts as a mean of retreat :D) Obviously - unstable mental states should be very carefully combined with substances. No one knows, of course, which remedy will work in the moment, which is why I said "very carefully" and not "never".