File photo: Researchers took neurons from rats and anchored them onto the scaffold, and the gel encouraged growth.

London - If you think your glass is always half empty, it could be because of a tiny region of the brain that teaches us to expect the worst.

Scientists say the habenula, a part of the brain half the size of a pea, plays an important role in learning from bad experiences. In those with an over-active habenula, it may be linked to depression and pessimism, a study concluded.

“The habenula tracks our experiences, responding more the worse something is expected to be,” said Dr Jonathan Roiser, of University College London’s Institute of Cognitive Neuroscience.

“In this study we showed that the habenula doesn’t just express whether something leads to negative events or not; it signals quite how much bad outcomes are expected.”

Random pictures were shown to 23 women, who were occasionally given a shock to the hand. The study, published in the journal Proceedings Of The National Academy Of Sciences, found the habenula reacted strongly when the women thought a shock might be imminent. - Daily Mail