WE’VE all done it — the cheeky e-mail about the boss that you send him by accident; toiling over an examination question only to realise you’ve got the wrong end of the stick; the go-for-broke call on red as the roulette ball lands on black.

That “cold sweat” moment — the split second when someone realises they have made a potentially costly mistake — has been found to set off mechanisms in the brain that could help scientists to understand mental health problems. According to neurologists from the University of Michigan, a part of the brain suddenly becomes more active when we realise that ill-judged actions carry serious consequences. The discovery could assist the understanding of conditions such as obsessive compulsive disorder (OCD) and depression.

The rostral anterior cingulate cortex, or rACC, has been found to go into overdrive when such an error is made. When the mistake does not carry a penalty, or when a correct action carries a reward, the same area of the brain is far less active.

Using brain imaging, the scientists have traced rACC activity for the first time and compared it with brain patterns in people with obsessive behavioural problems. They found that in the brains of OCD patients the rACC area, which is also associated with emotion, became much more active in response to an error that carried no serious consequences than it did in those people without the condition — suggesting it is linked to increased anxiety.

The research, published in the Journal of Neuroscience, involved 12 healthy adults having their brains scanned as they responded to a series of tests. Some of the tests carried a monetary reward, others carried penalties of the same size and some carried neither.

The participants had quickly to press a button to answer each test, which involved determining an odd letter among other letters. They were immediately told if they were wrong or too late in responding.

Stephan Taylor, lead author and associate professor in the Department of Psychiatry at the University of Michigan Medical School, said: “In general, the response to a mistake that cost them money was greater than the response to other mistakes, and the involvement of the rACC suggests the importance of emotions in decision processes,” he said. “It is very interesting that the same part of the brain that responded in our OCD study on regular errors [that carried no consequences] also responded in healthy individuals when we made the error count more.”

The researchers hope to study the impact of cognitive behavioural therapy — a form of “talking” therapy — on how OCD patients respond to their errors. “OCD patients may have a hyperactive response to making errors, with increased worry about having done something wrong,” Dr Taylor said.

“We hope this kind of research will help us get a handle on this condition.” The finding does not have immediate implications for OCD patients, he cautioned. But it could help in the development of new treatments.

Obsessive compulsive disorder is often characterised by untoward anxiety. Obsessions include unwanted thoughts that can trigger repetitive behaviour such as handwashing, counting and checking — rituals performed with the hope of preventing or dispelling obsessive thoughts.

OCD is listed by the World Health Organisation among the most debilitating illnesses and may affect 3 per cent of Britain’s population.

AN ALMIGHTY . . .

A woman thought that she had won €250,000 on the lottery, only to learn that her mother had put the ticket, which was in a trouser pocket, in the wash. The woman salvaged the ticket, which was still recognisable, but lottery organisers declared it invalid

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