Scientists find key to the making of memories

SCIENTISTS have found the secret of how memories are made in a discovery they described as “beautiful”.

The brain, they claim, makes two copies of every event.

Researchers said they were surprised to discover that the brain “doubles up” by making one memory for the present and one for the long term.

It had been thought that all memories start as shortterm and are then slowly converted into lifetime versions.

Experts said the findings, in research from MIT in the US and a team from Japan, were “beautiful and convincing”.

Two parts of the brain are involved in collecting and storing experiences.

The hippocampus collects short-term memories and the cortex retains long-term memories, a discovery made in the Fifties.

Scientists thought memories must be formed in the hippocampus and then moved to the cortex where they are “banked”.

The new experiments, by the Riken-MIT Centre for Neural Circuit Genetics, carried out on mice, have established a different theory.

They involved watching the way memories were formed as brain cells responded to a shock. Light was then beamed into the brain to control the activity of individual neurons, switching memories on and off.

The results, published in the journal Science, found that memories were formed simultaneously in the hippocampus and the cortex.

When scientists turned off the short-term memory, the shock event was forgotten. Yet the mice could be made to remember by manually switching the longterm memory on.

Prof Susumu Tonegawa, the director of the research centre, said: “This is a significant advance compared to previous knowledge – it’s a big shift.”

Dr Amy Milton, who researches memory at Cambridge University, said the study was “beautiful, elegant and extremely impressive”.

She told the BBC News website: “This is one study, but I think they’ve got a strong case, I think it’s convincing and I believe this will tell us about how memories are stored in humans as well.”