Scientists may have pinpointed the area in the brain where morality and emotions clash in dicey situations.

The area is the ventromedial prefrontal cortex (VMPC), report the researchers. Patients with damage to this region of the brain were quick to choose seemingly immoral choices when faced with life and death situations. The study has implications for the origins of human nature, and what happens emotions are taken out of decision making.

Michael Koenigs, PhD, of the National Institute of Neurological Disorders and Stroke, worked on the study while on staff in the neurology division of the University of Iowa Hospitals and Clinics.

Koenigs and colleagues studied six people who suffered VMPC damage as adults. The VMPC is involved in emotional responses and social emotions such as compassion, shame, and guilt, Koenigs' team notes.

For comparison, the researchers also looked at 12 healthy adults with no brain damage and 12 adults with brain damage that didn't affect the VMPC or other emotion-related areas.

In the study, participants read fictional scenarios that presented dilemmas, such as sacrificing one person's life to save the lives of others.

For example, one scenario featured a runaway boxcar careening towards a crowd. Study participants were asked if they would push one person off a bridge to save five other people from the boxcar.

Those with VMPC damage were twice as likely to agree with killing that one person to save the others. They also made similar choices in other personal, emotional, life-and-death scenarios. The 6 patients with VMPC damage also made these decisions faster than other participants.

However, these VMPC-damaged participants handled impersonal, low-stakes scenarios much like the other study participants.

The researchers aren't calling the VMPC-damaged participants cold or immoral. But they say the findings support the theory that the VMPC is involved in making personal, emotional, intense moral decisions.