that study linked above uses a synthetic cannaboid, which is ~100x more potent the the most potent bud, so im sure, that while the results are indeed accurate, the effect of naturally occuring cannaboids will have a slightly different (less) effect on the proliferation of brain cells as a whole.

Edit: The synthetic cannaboid is at least 100x more potent, and up to 800x more potent, that would certianlly present some skewed results in compraision to non-synthetic cannaboids.