A little digging found this article in 2010 Stroke:
Niacin Treatment of Stroke Increases Synaptic Plasticity and Axon Growth in Rats
Background and Purpose—Niacin is the most effective medication in current clinical use for increasing high-density lipoprotein cholesterol. We tested the hypothesis that niacin treatment of stroke promotes synaptic plasticity and axon growth in the ischemic brain.
Methods—Male Wistar rats were subjected to 2 hours of middle cerebral artery occlusion and treated with or without Niaspan (a prolonged-release formulation of niacin, 40 mg/kg) daily for 14 days starting 24 hours after middle cerebral artery occlusion. The expression of synaptophysin, Nogo receptor, Bielschowsky silver, brain-derived neurotrophic factor, and its receptor tropomyosin-related kinase B were measured by immunohistostaining and Western blot, respectively, in the ischemic brain. Complementing in vivo studies, primary cultured neurons were used to test the effect of niacin and high-density lipoprotein on neurite outgrowth and brain-derived neurotrophic factor/tropomyosin-related kinase B expression.
Results—Niaspan treatment of stroke significantly increased synaptophysin, Bielschowsky silver, brain-derived neurotrophic factor/tropomyosin-related kinase B expression, and decreased Nogo receptor expression in the ischemic brain compared with middle cerebral artery occlusion control animals (P-.05=""
Conclusions—Niacin treatment of stroke promotes synaptic plasticity and axon growth, which is mediated, at least partially, by the brain-derived neurotrophic factor/tropomyosin-related kinase B pathways.
UPDATE: There are some risks at the 6g/day level, but I have felt so good today that I am going to stay at 2 g/day.