There's much about the brain we still have to discover, and one of the unanswered questions surrounding this most vital of organs is how it uses up most of its energy. The brain claims around 20 percent of the total oxygen used to fuel our bodies, yet we don't know where most of that goes. Now an IBM researcher thinks he might have solved the mystery.

James Kozloski, who works as a computer neuroscientist at IBM's Thomas J. Watson Research Centre, says the brain is constantly looping signals through established pathways - pathways that can be thought of as city street maps for our minds. The brain repeatedly retraces its steps through these pathways, covering three different areas of functionality: sensory (what’s currently happening), behavioural (what we can do about it), and limbic (what it means to us).

Kozloski calls this closed-loop model the "Grand Loop", and hypothesises that these repeated cycles are the reason the brain needs so much energy, even when we're not actively solving maths puzzles or trying to juggle. He successfully ran his hypothesis through the neural tissue simulator at IBM, which can produce an accurate model of the way neurons fire in the human brain.

"The brain consumes a great amount of energy doing nothing," Kozloski explained to Popular Science. "It's a great mystery of neuroscience. You don’t spend that much energy on noise unless there’s a really good reason."

Kozloski thinks his idea could explain how we draw from past experiences to inform our reaction to new ones - we quickly consult our 'city map' to decide what to do next.

It could also help in the treatment of degenerative brain diseases such as Huntington's, he says, because it might provide an explanation for why one defective gene is able to cause such havoc inside the brain, knocking the Grand Loop off course.

The research has been published in the journal Frontiers in Neuroanatomy.