A neuroscientist says a new insight into how memory works could change the way brain diseases are treated.

Scientists in Australia and the United States say they have found that the brain has a second way of storing information.

Garvan Institute researcher Bryce Vissel says the finding could have major implications for treating people who have lost their ability to remember because of brain injury or a disease like Alzheimer's.

For two or three decades, researchers have thought they knew how memories are formed.

That understanding has centred on an essential mechanism inside the hippocampus of the brain called the NMDA receptor.

"All learning theory, all textbooks, all talk about this particular process," Dr Vissel said.

"That's driven how we design drugs; it's driven how we think about memory formation; it's driven how we try to treat these disorders.

"Now that we've discovered this second mechanism, now that we've kicked this idea off, we can start to think about ... [developing] drugs that work on this second mechanism."

Dr Vissel says his team made the discovery by trying to artificially replicate the processes of the NMDA receptor.

"What we found was that this mechanism actually exists in nature and we didn't need to replicate it artificially," he said.

"But it only happens in certain circumstances.

"When we discovered that, it was a kind of a eureka moment: 'Oh my gosh, there's a completely different mechanism of memory formation in the brain'."

This new learning mechanism comes into effect in a process known as 'second learning'.

Dr Vissel says this happens when you apply the rules of something you have learnt before to a new - but similar - situation.

Dr Michael Fanselow, a learning theorist from the University of California who collaborated on the research over the past six years, says the memory mechanism needs to be investigated further.

"If we figure out the rules by which this kind of mechanism is engaged in, then in situations where learning ... and forming new memories is difficult ... we may be able to overcome those kind of deficits," he said.

"The one that immediately comes to mind, I think, is in Alzheimer's disease, where you have the inability to form new memories.

The researchers say that also has the potential to revolutionise learning in the classroom.

But there is more learning ahead before that becomes a reality.

The study's findings are now published online in the journal PloS ONE.