It is understood that memory involves strenghtening of synapses, the connections between neurons but the molecular mechanism was not.
Now Santa Barbara scientists say that in rats the production of proteins needed to cement memories can only happen when the RNA is produced but the the RNA is paralysed by a "silencing" molecule, a protein, until it is needed.
ScienceDaily (Dec. 25, 2009) — Scientists at UC Santa Barbara have made a major discovery in how the brain encodes memories. The finding, published in the December 24 issue of the journal Neuron, could eventually lead to the development of new drugs to aid memory.
"One of the most important processes is that the synapses -- which cement those memories into place -- have to be strengthened,"..Part of strengthening a synapse involves making new proteins. Those proteins build the synapse and make it stronger. Just like with exercise, when new proteins must build up muscle mass, synapses must also make more protein when recording memories. In this research, the regulation and control of that process was uncovered.
The production of new proteins can only occur when the RNA that will make the required proteins is turned on. Until then, the RNA is "locked up" by a silencing molecule, which is a micro RNA. The RNA and micro RNA are part of a package that includes several other proteins.
"One reason why this is interesting is that scientists have been perplexed for some time as to why, when synapses are strengthened, you need to have proteins degrade and also make new proteins," said Kosik. "You have the degradation of proteins going on side by side with the synthesis of new proteins. So we have now resolved this paradox. We show that protein degradation and synthesis go hand in hand. The degradation permits the synthesis to occur. That's the elegant scientific finding that comes out of this."
How the Brain Encodes Memories at a Cellular Level