Electric currents may boost memory

Electric currents could be the key to treating memory impairments caused by conditions such as stroke, early-stage Alzheimer's disease, traumatic brain injury, cardiac arrest and the memory problems that occur in healthy ageing.

Researchers have found that stimulating a particular region in the brain via non-invasive delivery of electrical current using magnetic pulses, called Transcranial Magnetic Stimulation (TMS), improves memory.

"We show for the first time that you can specifically change memory functions of the brain in adults without surgery or drugs, which have not proven effective," said senior author Joel Voss, assistant professor of medical social sciences at Northwestern University Feinberg School of Medicine in the US.

"This non-invasive stimulation improves the ability to learn new things. It has tremendous potential for treating memory disorders," Voss added.

It is not possible to directly stimulate the hippocampus (a key memory structure) with TMS because it is too deep in the brain for the magnetic fields to penetrate.

So, using an MRI scan, the researchers identified a superficial brain region a mere centimetre from the surface of the skull with high connectivity to the hippocampus.

The researchers wanted to see if directing the stimulation to this spot would in turn stimulate the hippocampus. It did.

"I was astonished to see that it worked so specifically," Voss said.

When TMS was used to stimulate this spot, regions in the brain involved with the hippocampus became more synchronised with each other.

The more those regions worked together due to the stimulation, the better people were able to learn new information.

The study involving 16 healthy adults ages 21 to 40 will be published in the journal Science.