Probably each one of us is aware of the apparent ill-effects of long term depression. A new study at the University of Wisconsin-Madison indicates yet another astonishing effect of the condition. The experts suggest that patients who are depressed seem to be incapable of sustaining activity in the areas of their brain linked with positive emotion.
A commonly held notion was that depressed individuals seem to show less brain activity in areas associated with positive emotion. The new study however indicates similar initial levels of activity, but an inability to sustain them over time.
“Anhedonia, the inability to experience pleasure in things normally rewarding, is a cardinal symptom of depression,” reveals UW-Madison graduate student Aaron Heller, who led the project. “Scientists have generally thought that anhedonia is associated with a general reduction of activity in brain areas thought to be important for positive emotion and reward. In fact, we found that depressed patients showed normal levels of activity early on in the experiment. However, towards the end of the experiment, those levels of activity dropped off precipitously. ”
Heller further continues, “Those depressed subjects who were better able to sustain activity in brain regions related to positive emotion and reward also reported higher levels of positive emotion in their everyday experience,”.
“Being able to sustain and even enhance one’s own positive emotional experience is a critical component of health and well-being,” marked the study’s senior author, Richard Davidson, professor of psychology and psychiatry and director of both the UW-Madison Center for Investigating Healthy Minds and the Waisman Laboratory for Brain Imaging and Behavior. “These findings may lead to therapeutic interventions that enable depressed individuals to better sustain positive emotion in their daily lives.”
As part of the study, the scientists evaluated 27 depressed patients and 19 control participants. The participants were presented with visual images that were intended to evoke either a positive or a negative emotional response. The subjects were then instructed to use cognitive strategies to augment, lower or maintain their emotional responses to the images. They were told to do this by imagining themselves in similar scenarios while viewing these images.
Equipped with functional magnetic resonance imaging (fMRI), the experts then measured brain activity in the target areas. Next, the scientists analyzed the extent to which activation in the brain’s reward focused on positive pictures. It was found to have sustained over time.
The new work was reported online this week in the Proceedings of the National Academy of Sciences.