Why some forget weddings

Weddings and other big events are the stuff of memories. Now researchers have found a genetic change that makes some people remember them better than others.

The findings, published in the journal Nature Neuroscience, could help in the treatment of a number of psychiatric conditions, including post-trauma disorders, the researchers said.

Scientists have long recognised a link between memory and strong emotional events and the important evolutionary role it plays in remembering dangerous or favourable situations, said Andreas Papassotiropoulos, a researcher who worked on the study.

But the mechanism that triggers or regulates these responses was unclear, Papassotiropoulos, a psychiatrist at the University of Basel, said.

Proof of principle
"This is the first proof of principle that we are able to identify genes and variants for emotional memory in humans," he said in a telephone interview.

Researchers around the world have been scouring the human genome to find genetic links to various diseases and conditions in the hope of developing new ways to prevent or treat them.

Papassotiropoulos, along with his colleague Dominique de Quervain at the University of Zurich, said a readily available database of human genes allowed them to zero in on a gene they believed was related to emotional memories.

In their study, the researchers collected DNA from 435 Swiss students and showed them a series of pictures such as a baby laughing, a car accident or a table. Then they asked them to remember what they had seen.

A wide range
Most people remembered the emotional pictures better than the neutral ones, but there was a wide range in how well some people recalled the highly charged images, Papassotiropoulos, said.

"There was a huge spectrum of this memory performance," he said. "The result was people with the deleted gene remembered emotional pictures better than people without the deletion."

The team also wanted to see what would happen to people carrying this genetic change who had very strong negative emotional memories.

Gene tied to PTSD
To do this, they interviewed a group of refugees from Rwanda's bloody civil war and found that survivors with the genetic change suffered more severe cases of post-traumatic stress syndrome, Papassotiropoulos said.

This suggested that the same genetic mutation that helps people remember how to avoid a dangerous situation or recall a happy experience could also worsen bad memories, the researchers said.

"The deletion variant was not related to whether they had the disease or not but it was related to the amount of traumatic memories," he said.

The next step, Papassotiropoulos said, is to search through the whole human genome to find genes related to memory researchers did not know about before.

The findings also offer hope that one day scientists can develop drugs targeting a range of psychiatric conditions such as depression and anxiety where memory plays a key role, he said.

"This will open the avenue for new pharmacology treatments," he said. "We hope we will identify some of the genes related to these conditions." – (Reuters Health)

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July 2007