How the brain works ... what it does, how it does it, and how well it does it ... is a matter of how neurons are arranged in relation to each other, in circuits. But that is only part of the story. These neurons also need to function properly, and the connections between them need to function properly. For instance, it is thought that Einstein's brain (he was a smart-guy, we assume) was not especially large, but it is though the had a somewhat better than average setup for keeping his neurons happy.
A protein called postsynaptic density-95 (PSD-95) acts as a structural element around which other components of the synapse ... the "connection" between two nerurons" is built. The more PSD-95 available, the better the connection, according to MIT researchers with a recent paper in Nature.
It was already known that mice with an altered PDD95 gene ... to produce an ineffective protein ... had trouble with memory and learning.
The newly reported research describes the molecular processes associated with the function of this protein. There could be real-life applications of this work. According to Morgan H. Sheng, Menicon Professor of Neuroscience at MIT's Picower Institute for Learning and Memory:
"Adding a phosphate group to a single amino acid allows PSD-95 to promote synapse size and strength, ... Therefore, promoting this process could help improve cognitive function."
This will be in the November 8th Nature and is reported here as well.
From time to time you see reports about some minor variation of an in-body substance - or just an increase in the level - that has wonderful cognitive or physiological effects. I always wonder though: if it's so great, why aren't our bodies producing it in the needed quantity already? The suspicion is of course that either it's not really all that great; or it has side effects substantial enough to offset the benefits; or quite possibly both.
It's also possible that even if a mutant trait arose from this protein that caused a substantial leap in cognitive ability, that it wouldn't be something that would be selected for because greater intelligence does not increase reproduction. In fact, judging from all my intelligent nerdy friends in comparison to my meat head jock friends... I think being intelligent makes a person less likely to reproduce.
But you're right, it could have some side effects. It could be that it's perfectly well balanced as it is. Or it could be that the random mutation needed to produce more/better proteins just hasn't come up yet.
I would like to see what happens in mice if they produce MASSIVE quantities of this protein. I would also like to see what happens when they produce the modified protein in normal and massive amounts. Secret of Nyhm here we come!
Also, I would like to see a study that measures the relative levels of PSD 95 in various animals of varying intelligence to see if there is a correlation.