Want to light up the pleasure centre in your brain? Just pay your taxes on time, and then donate a little extra to feed the children of the lesser God who hardly get to eat two square meals a day.

A team of international researchers has carried out a study and found that doing those deeds give one the same sort of satisfaction one derives from feeding his or her own hunger pangs, the ScienceDaily reported.

"What this shows to someone who designs tax policy is that taxes aren't all bad. Paying taxes can make citizens happy. People are, to varying degrees, pure altruists. On top of that they like that warm glow they get from charitable giving. Until now we couldn't trace that in the brain," lead researcher Prof Ulrich Mayr was quoted as saying.

The team came to the conclusion after analysing a group of 19 women -- the researchers gave the participants $100 and then scanned their brains with functional magnetic resonance imaging.

They monitored the brain activity of the participants as their money went to food banks through mandatory taxation, and as they made choices about whether to give more money voluntarily or keep it for themselves. The participants laid on their backs in the scanner for an hour-long session and viewed the financial transfers on a computer screen.

The scanner used a super-cooled magnet, carefully tuned radio waves and powerful computers to calculate what parts of the brain were active as subjects saw their money go to the food banks and made 'yes' or 'no' decisions on the additional giving.

The researchers found that two evolutionarily ancient regions deep in the brain -- the caudate nucleus and the nucleus accumbens -- fired when subjects saw the charity getting the money.

The activation was found to be even larger when people gave the money voluntarily, instead of just paying it as taxes. These brain regions are the same ones that fire when basic needs such as food and pleasures are satisfied.

"The surprising element for us was that in a situation in which your money is simply given to others -- where you do not have a free choice -- you still get reward centre activity," Prof Mayr said.

According to the researchers, neural firing in this fundamental, primitive part of the brain is larger when the money goes to a non-profit charity to help other people.

"Neural activation from mandatory taxation helps predict who will give. We could call the people whose brains light up more when money goes to charity than to themselves altruists.

"The others are egoists. Based on what we saw in the experiments, we can use this classification to predict how much people are willing to give when the choice is theirs," Prof Mayr of the University of Oregon was quoted as saying.