It is commonly reported by people suffering from chronic stress or a major depression that they feel like they are ‘not acting like themselves’. Fascinating brain research in the past ten years has already shown that this experience is supported by heavy neural changes in depressed brains. In a depression, people’s brains do not just alter: they significantly shrink. Until now, nobody really knew how this happened. What causes a human brain to shrink? And what can be done to stop this process?
In a recent experiment, published in Nature Medicine, researchers compared the gene expression of depressed subjects with that of their healthy counterparts. They were then able to point out five specific genes which were less active in depressed brains. All these genes were involved in constructing new brain synapses – the junctions between brain cells which enable them to communicate. This group of genes turned out to be controlled by one commander gene, GATA1.
When GATA1 was activated in rodents in a control experiment, all five synapse-constructing genes were suppressed and no new synapses were created. Moreover, existing synapses decreased in functionality. As a result, neural circuits which are normally involved in emotion or cognition, were severely disrupted. In accordance with this, the rodent models clearly showed depressed behavior.
The researchers hope that their results will improve research to new medications and treatments for depression and major stress. As Ronald Duman, one of the authors and a professor of psychiatry, neurobiology and pharmacology, says: “We hope that by enhancing synaptic connections, either with novel medications or behavioral therapy, we can develop more effective antidepressant therapies.”
Kang, Hyo Jung et al. (2012). ‘Decreased expression of synapse-related genes and loss of synapses in major depressive disorder’ In: Nature Medicine. Doi: 10.1038/nm.2886