memory and marlboro smokes

according to new scientist magazine, nicotine may impair the formation of new hippocampal cells. they say specifically Short-term cognitive problems in smokers trying to kick the habit are well documented… while they are smoking, the stimulant effect of nicotine masks the loss in neuronal plasticity. When they stop smoking, these deficiencies remain."

does this mean that, under the influence of nicotine, it is possible that the brain (neurons all hopped up and whatnot) makes do with less? like, with nicotine (and (BIG PERHAPS!) perhaps many uppers) the brain can make do with less neurons and/or neuronal circuits?

has there been any research one way or another (that is, uppers (or nicotine) make the brain more sleek, or less sleek (sleek being in terms of number of processing neurons versus output?))?

jb
here

p.s.- like, any system wants to be the most efficient system (i know, not really proven- DAMN those mathematicians!), and if you introduce a substance which allows neural nets to be more effective and/or efficient, it will become Hyper-efficient.

so that when you reduce the amount of the substance, the whole system comes off slightly retarded.