4 replies to this topic

[dopamine]

It could be anticholinergic effects from the DMAE competition with choline for cholingeric uptake to the brain. DMAE is generally regarded as useless as a "cognitive enhancer," but some notice mood improvements (probably due to the fact that many antidepressants are also anticholingerics). Also read this thread from M&M a couple of years back on the topic, especially shpongled's thoughtful reply.

[digfarenough]

My guess would be as follows. It is likely that with acetylcholine, like all neuromodulators, fluctuations in levels are important (certainly true for dopamine, too). When acetylcholine levels are high, in both cortex and in hippocampus it has been shown that strong synaptic potentiation is easier to induce at intrinsic synapses, but simultaneously ACh decreases synaptic efficacy at those synapses (messages sent over them are weakened or not passed, so memories are "written" strongly, but are less retrievable). When acetylcholine levels are low, potentiation is less inducible, but those intrinsic synapses become active (so memories can be retrieved over them, but not "written"). So you need to be able to alternate between low and high ACh levels as situations demand.

If acetylcholinesterase levels are too high, you get a bit toward the Alzheimer's-y end of the spectrum, so by lowering them memory improvments should be possible (up to a point). Likewise, if you have too much ACh all the time, you might be less able to retrieve older memories, so increasing ACh-esterase levels may improve your memory (up to a point). Granted, I haven't read the paper you mentioned, so could be way off!

This 1995 paper is old, but if you're interested in the effects of neuromodulators on the brain, it is a good summary: http://people.bu.edu...elmoBBR1995.pdf