Why would there be interest in this particular compound? The track record from the comparison of active compounds that are primary amines, and their N-methyl homologues, has shown that, in general, the stimulant component might be maintained, but the "psychedelic" contribution is generally much reduced. MDMA is, of course, an exception, but then, that particular compound is a one-of-a-kind thing which simply defies all the rules anyway, and I drop it from this kind of reasoning. And as 4-MA is a pretty pushy stimulant with little if any sensory sparkle, why bother with the N-methyl compound at all?
Enough editorial. Back to historic technicalities. In truth, METHYL-MA is a well studied drug, at least in animals. In both mice and rats, it is an exceptionally potent agent in creating the state of catatonia. Animal studies, prompted by the clandestine synthesis of METHYL-MA, have shown that there is indeed locomotor stimulation and some central effects, but these effects are somehow different than those of a simple amphetamine-like agent. The experimenter's conclusions, based on its structural resemblance to 4-MA and its proclivity to produce catatonia in some animal species and the ever-present possibility that there might be unsuspected neurochemical changes to be seen with its use, are that human experimentation should be discouraged. I have come to the same conclusion, but in my case this is based on a much more succinct observation: I tried it and I didn't like it.