London: Scientists have identified a brain chemical that appears to boost memory in rats, a discovery they claim could lead to new treatments for cognitive diseases like Alzheimer`s and dementia.
A team researchers at Mount Sinai School of Medicine in New York found that IGF-II, a molecule that occurs naturally in the human brain during memory formation, plays a key role in the laying down and the strengthening of memories.
The chemical is found in relatively high levels in the hippocampus -- the brain`s memory hub. However, its levels decline with age.
According to the researchers, learning more about how this chemical affects memory, could lead to new emory-boosting drugs for Alzheimer`s, stroke and other conditions that rob people of their ability to remember even the simplest things.
The reverse, they said, may also be possible, with pills that wipe painful memories being used to help soldiers erase the horrors of battle, as well as those haunted by memories of
car crashes and sufferers of crippling phobia, the Daily Mail reported.
For their research, the scientists gave mild electric shocks to rats when they entered the darker side of a box.
As the rodents normally like shaded spots, any reluctance to re-enter the area was taken to mean they remembered the painful consequences. So, the more the animal avoided the darkness, the better it was at remembering where not to go.
Tests showed that levels of IGF-II rose as the animals learnt to avoid the dark spot -- and that giving them an injection of the substance boosted memory even further.
New memories were strengthened and were slower to break down. In other words, the creatures found it harder to forget.
Examination of the animals` brains reviled that IGF-II had strengthened the cellular connections and mechanisms underlying long-term memory, the researchers reported in the journal Nature.
Senior study author Cristina Alberini, a professor of neuroscience at Mount Sinai, said: "The implications of these data are far-reaching and give us new clues about how to investigate memory loss and forgetfulness in people with cognitive impairment, like those with Alzheimer`s disease, stroke or dementia.
"This study is the first step to understanding the benefits of IGF-II. We have identified some of the mechanisms associated with this effect and look forward to studying them
and exploring the clinical relevance of IGF-II."
Other experiments also showed that blocking IGF-II stops long-lasting memories from forming, a finding researchers said could also lead to drugs that could erase bad memories – a process known to medics as extinction.
Dr Thomas Insel of the National Institutes of Health, which funded the research, said: "As we learn more about such mechanisms of fear memory formation and extinction we hope to apply this knowledge to address clinical problems, including post-traumatic stress disorder."
The ability to erase painful memories has been the stuff of science fiction and Hollywood blockbusters for decades.
In the film `Eternal Sunshine of the Spotless Mind`, a couple, played by Kate Winslet and Jim Carrey, undergo a procedure known as `targeted memory erasure` to wipe out all recollection of each other after their relationship turns sour.
Dutch researchers recently discovered that beta-blocker drugs used to treat heart disease may also help patients to banish bad memories.