Dw629

Very well written and researched post, I'm surprised by the lack of comments. 

One small additional note on what you briefly touched upon: neuronal circuitry organized in a more sparse and efficient manner is associated with higher intelligence.

The cerebral cortex of high-IQ individuals is characterized by a low degree of neurite density and orientation dispersion [...] Intellectual performance is likely to benefit from this kind of microstructural architecture since restricting synaptic connections to an efficient minimum facilitates the differentiation of

Yeah unfortunately it seems to be the case that no one has really seriously tried (ie invested a lot of resources, on the scale of a large company or a government) to do R&D on significantly increasing IQ in healthy people through drugs, but I won’t get into that here.
If you’re interested in this area then I really do recommend to talk with the people at Nootopics. 
Everychem is the small company that has synthesized most of the drugs I’ve listed and sells them for research (so really they are just research chemicals), but even though this is clear... (read more)

Since 1999 there have been "Doogie" mice that were genetically engineered to overexpress NR2B in their brain, and they were found to have significantly greater cognitive function than their normal counterparts, even performing twice as well on one learning test.
No drug AFAIK has been developed that selectively (and safely) enhances NR2B function in the brain, which would best be achieved by a positive allosteric modulator of NR2B, but also no drug company has wanted to or tried to specifically increase general intelligence/IQ in people, and increasing IQ i... (read more)