Scientists seeking ways to help people retain the cognitive abilities in advanced age say they've identified some new genes apparently involved in long-term memory.
In a study of the genome of the common worm, around 750 genes that play a part in the formation of long-term memories were identified, including many not identified before that could be candidates for further research, says Coleen Murphy, a professor of molecular biology at Princeton University.
"We want to know, are there ways to extend memory?" she says. "And eventually, we would like to ask, are there compounds that could maintain memory with age?"
The newly identified genes are activated by a molecule named CREB, for cAMP-response element-binding protein, an activation assumed to be a requirement for the creation of long-term memories in many creatures, including worms and mice, the researchers report in the journal Neuron.
"There is a pretty direct relationship between CREB and long-term memory," Murphy says, "and many organisms lose CREB as they age."
An examination of CREB-activated genes and exactly how they work -- or don't work -- could lead to a better understanding of why some organisms are prone to losing long-term memories when they begin to get older.
How to you study long-term memory in worms?
The researchers instilled memories in the worms by getting them to associate the smell of butterscotch with feeding time, something the worms were able to hold on to for around 16 hours -- a long time if you're a worm.
The scientists then scanned the genomes of the trained worms and compared them to worms that had not been trained, looking for signs of genes activated by CREB.
In the memory-trained worms, they found 757 CREB-activated genes, mostly in worm cells known as AIM interneurons.
Genes in the AIM interneurons of non-trained worms were not activated, the researchers say.
The next thing to study, Murphy says, is exactly what the newly identified long-term memory genes do after they're activated by CREB.
They might be involved in strengthening connections between brain neurons as part of forming long-term memories, the researchers say.
Worms, with their simple nervous systems, are ideal for exploring such questions, Murphy says.
The worm used in the study, Caenorhabditis elegans, possesses just 302 neurons, compared to the typical mammalian brain with its billions of cells.
"Worms use the same molecular machinery that higher organisms, including mammals, use to carry out long-term memory," Murphy says. "We hope that other researchers will take our list and look at the genes to see whether they are important in more complex organisms."
