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Zapping the hippocampus reverses age-related memory loss

Zapping the hippocampus reverses age-related memory loss
24th April 2019

Sending an electrical current through the hippocampus of elderly people has helped to sharpen their memories, scientists claim.

Researchers from Northwestern University in Illinois found that the over-64s could benefit from having areas of their brain stimulated.

They found the volunteers who underwent the therapy could not be differentiated from adults a decade younger in memory tests.

It is not the first time that medical trials have used electrical currents on the brain to help improve the way it functions, with this latest study corroborating previous evidence of its benefits.

While 16 individuals between the ages of 64 and 80 took part in the research, they all had the expected level of memory loss you would expect in elderly people.

It is not therefore thought that sending an electric current through the hippocampus of anyone with dementia could make a difference.

Each of the participants had their brains zapped for 20 minutes a day over five days, resulting in better cognitive functioning.

Dr Joel Voss, lead investigator, said: “Older people's memory got better up to the level that we could no longer tell them apart from younger people. They got substantially better.”

Test results for the over-64s were 15 per cent worse than 18 to 34-year-olds prior to the electrical therapy, which is known as transcranial magnetic stimulation (TMS).

The older demographic scored an average of 40 in the first round of tests, which involved remembering specific, made-up relationships between objects.

In comparison, the younger group scored 55, which the older participants also managed to achieve after having TMS.

The electrical current helped to stimulate the parietal lobe, which is deep inside the hippocampus, and controls this part of the brain.

Scientists targeted this area, just above the left ear, because it’s responsible for creating new memories, learning and emotional control.

TMS is delivered using a metal coil placed against the scalp, making it a non-invasive treatment option.

Dr Voss added: “If you think about the brain's memory network as generating one unit of activity every time it tries to memorise a picture, brain stimulation made it so that now the same type of picture would generate two units of activity.

“This increase in activity means stimulation enhanced excitability - and that's important because excitability is a marker for good memory formation.”

All of the activity that occurs in the brain is the result of electrical signals, which can be mimicked with artificial current.

Interruptions to the natural electrical impulses can affect the memory - both in terms of recalling things from the past and creating new memories.

A recent study carried out at Boston University found that brainwaves in two different parts of the organ can fall out of rhythm, which often happens in older people.

This often affects their short-term memory, but when the temporal lobe and prefrontal cortex were stimulated they became synchronised once more.

What this means for the future could be that memory loss becomes treatable and not an inevitable part of old age.