How are memories formed? The question has perplexed scientists for years, but now it seems we're a step closer to solving it.

The leading candidate is a process called long-term potentiation (LTP), in which the connections between individual brain cells get stronger the more often they are used, such as during learning. But while LTP has often been observed in slices of brain in the lab, it has been difficult to record in a living brain as learning was taking place.

Now Liliana Minichiello and her colleagues at the European Molecular Biology Laboratory in Monterotondo, Italy, and the Pablo de Olavide University in Seville, Spain, appear to have done just that by isolating a molecule that initiates a signalling pathway for LTP in the brain of a living mouse. The finding builds on a technique they developed last year to record LTP in a mouse hippocampus - a brain region involved in learning - while the animal was being trained to blink in response to a tone.

In the new study, the team used mice with a defective version of a receptor molecule called TrkB, found on the surface of brain cells in the hippocampus. The mice were unable to learn or initiate LTP in response to familiar stimuli, indicating TrkB is a key memory molecule. The finding will be published in Learning and Memory this week.

Minichiello hopes that as they identify more molecules involved in initiating LTP, this could pave the way for drugs to combat Alzheimer's disease, or to enhance memory capability generally.

From issue 2586 of New Scientist magazine, 15 January 2007, page 16

Maybe one day we will be able record our raw memories to another physical medium..

While LTP is one of the leading contenders for memory formation, it needs to be expanded drastically. Researchers believe LTP does in fact hold the key to declarative memories. The trick is, declarative memories are formed by interactions of MANY neurons not just one. LTP has accounted for one neuronal strengthening. Has anybody read anything about how LTP 'synchronizes' with other neurons? Are astrocytes involved in some way? I think there is a lot that can be said for neuroglia. I believe neuroglia deserve much more respect than we give them.