Sneak peek into how our working memory functions

Ever wondered how your working memory functions in the brain? A new study finds that bursts of neural activity take place as the brain holds information in mind.

When the mind holds a sentence just read or a phone number that one is about to dial, then the individual is engaging a critical brain system known as working memory.

The new study upends the notion that brain cells associated with information fire continuously and instead reveals that as information is held in working memory, neurons -- nerve cells -- fire in sporadic and coordinated bursts.

"Your brain operates in a very sporadic, periodic way, with lots of gaps in between the information the brain represents," said one of the lead authors Mikael Lundqvist, postdoctoral researcher at the Massachusetts Institute Of Technology (MIT) in the US.

Our brain actually works in a very periodic fashion, sending packets of information around.

These cyclical bursts could help the brain to hold multiple items in working memory at the same time, the researchers explained.

"By having these different bursts coming at different moments in time, you can keep different items in memory separate from one another," added one of the authors Earl Miller, professor at MIT.

It would be worthwhile to look for this kind of cyclical activity in other cognitive functions such as attention, the researchers suggested in the study, published in the journal Neuron.

The team recorded neuron activity in animals as they were shown a sequence of three coloured squares, each in a different location.

Then, the squares were shown again, but one of them had changed colour.

The animals were trained to respond when they noticed the square that had changed colour -- a task requiring them to hold all three squares in working memory for about two seconds.

The researchers found that as the items were held in working memory, ensembles of neurons in the prefrontal cortex were active in brief bursts, and these bursts only occurred in recording sites in which information about the squares was stored.

The bursting was most frequent at the beginning of the task, when the information was encoded, and at the end, when the memories were read out.