as for the brown endowment, it is relatively small but brown is also a relatively small place
in terms of endowment per student brown is far ahead of huge schools like columbia, penn, and cornell.
that being said, i am now at harvard which has an ungodly endowment (by which i mean larger than the Vatican endowment). how does this affect undergrad students? not in any meaningful way. occasionally there are silly luxuries at harvard that don't regularly happen at brown (like free cocktail parties)--but it has little effect on quality of education or opportunities. (the one place it makes a real difference is financial aid)
as for your PLME question, PLME advising wasn't cut, it was simply reorganized. they changed the PLME advising system to make it more effective, not because of budget constaints (under the old system, most PLME's never made real use of the advising office).
so to put you at ease, at Brown and as a PLME, you will have great advising and research opportunties in neuroscience
