The brain is an incredibly complex circuit of biological wiring that determines how you experience and interact with the world around you. Your brain is what makes you you. Some of you may be aware though that biology isn’t always perfect and that can end in conditions that some might consider to not be biological norms. This idea has led to the investigation into the wiring of particular neurons and the expression of certain genes that might be linked to depression.
Types of genes like protocadherin determine the way in which particular neurons are dispersed throughout the brains biology and ensures that proper connections are established to allow for communication. In relevance to this article, a single C-type protocadherin gene controls the distribution of neurons that are associated with the neurotransmitter serotonin. You’ve probably heard of serotonin before; it is a chemical that is responsible for maintaining your mood as well as appetite, digestion, sexual desire, memory and sleep. There is also a link between depression and serotonin but scientists do not know if it is depression that causes low levels of serotonin or the low levels causing depression.
The new research shows that the removal of the gene Pcdhαc2 resulted in mice acting more depressed. This is an interesting concept for some people with the question most usually asked being “How do you know if a mouse is depressed?” The answer is one that is derived from particular behaviours displayed by the mice that could be extrapolated to them being depressed. The behaviour tested here was the likelihood of the mice ‘giving up’ on their own survival. Two groups of mice were forced to swim for an extended period of time; one control group and the other with the Pcdhαc2 removed. The mice without the Pcdhαc2 gene gave up swimming more often than the controlled group. Upon further investigation, they found that there was no differences in their muscles so it couldn’t have been due to fatigue; it could be explained by a depressed mental state.
When investigating the brain structures of mice with the gene removed, they discovered that the neurons responsible for the release of serotonin had clustered and had become ‘tangled’. The gene controls particular proteins that are active in the growth of neurons but without the protein, the neurons can’t branch to particular areas of the brain. This results in these areas not getting sufficient serotonin levels, potentially resulting in alter moods and abnormalities in the functions mentioned previously. This study might provide insight into similar mental illnesses that might stem from the incorrect wiring of neurons in the brain allowing for better diagnostics and treatment in the future.