To conduct the experiment researchers assembled 15 people with untreated depression, 24 people who had sought treatment for depression but had not responded to numerous medications and 37 non-depressed people that were similar in age, gender and education.
Two interesting discoveries were made when MRI’s were taken of the participants brain. In nearly all of those suffering from depression there was a weakened connection between the superior and inferior orbitofrontal cortex on the left side of the brain and a stronger connection on the right. This helps explain why those suffering from depression have a dulled sense of pleasure but will feel negative emotions like rejection more acutely.
The second discovery has to do with how those suffering from depression relate to others. People suffering from depression were also to found to have a weaker connection between mirror neurons. These neurons are affected by watching the actions of others and then prep the muscles of the body to perform an appropriate response. In this way the mirror neurons are believed to help us interpret and anticipate the thoughts and actions of others creating feelings of closeness and understanding. The weakened connection could help explain why those suffering from depression have trouble relating to others and experience feelings of isolation.
The hope is that, by better understanding how depression affects the brain, doctors will be better able to help those suffering from depression by creating more targeted and effective medications.