Recurrent Depression Linked to Amygdala Disconnection from Emotional Network
Researchers from the University of Illinois at Chicago have discovered a disconnection in an emotion-processing brain network in people with major depression. The findings will help to assess which patients would benefit more from anti-depressant treatments to avoid recurrent depression episodes. The study has been published in the journal Psychological Medicine.
50% of people who suffer a depressive episode will experience another one within the following two years. Depression has been attributed to different patterns of failed brain connectivity. On the one hand, it has been observed a disconnection between brain areas that process emotions and are involved in problem-solving. On the other hand, the hyperconnectivity of the resting network -the area that becomes active during ruminative thinking – has also been found to be related to major depression.
Functional magnetic resonance imaging to prevent new depression episodes
In their last study, Dr. Langenecker and his team wanted to test if there are different connectivity patterns between people who suffer one or several depression episodes. The researchers scanned the brains of 77 people by functional magnetic resonance imaging (fMRI). The researchers compared the brain scans of healthy people with others suffering their first or second depression episode. The scans were taken on a resting state, and none of the tested individuals was taking any medication. The researchers found that the amygdala – a part of the limbic system with a primary role in emotional reactions – is disconnected from the rest of the emotional network in sufferers of recurrent depression episodes. The disconnection might affect the accuracy of emotional processing and lead to assess neutral events as negative. Besides, people who had experienced at least one depression episode had an increased connectivity between the resting and cognitive networks, which be an adaptation to help regulate emotional bias.
Longer-term studies should be conducted in the future to confirm the validity of this experiment. fMRI scans could then be used to detect people at risk of recurrent depression episodes and help assess the need of maintenance or preventive treatments.
Source: University of Illinois at Chicago