Spring is in the air and the days are getting longer. The sunshine helps those with seasonal affective disorder which manifests in symptoms of depression, sadness and lethargy. Others may just feel a better sense of well being by being more active outdoors in the sunshine which raises chemical neurotransmitters such as serotonin and dopamine. If you are one of those people that tend to be down and depressed irregardless of the seasons, you may fall into one of those categories of a deeper chemical cause of depression.
Roberto Malinow and his group of researchers at the University of California, San Diego studied an evolutionary ancient region deep inside the brain known as the “lateral habenula”. Neurons in this area are activated by unexpected negative events, such as punishment and absence of an anticipated reward. For example, if you were told as a child that you would be rewarded with a juice box after doing a certain activity and that was withheld, this would heighten the activity of the lateral habenula. Hyperactivity in this part of the brain is linked with depression-like behavior in rodents. While in people, low levels of serotonin are linked with a rise in the lateral habenula. This has lead to the idea that this area is a key part of a “disappointment circuit”.
What makes this region in the brain so unusual is that it lacks the standard equipment the brain uses to reduce overactivity. Other parts of the brain have mechanisms in which opposing neurons either increase activity by secreting the chemical glutamate or decrease activity by secreting the chemical GABA. The lateral habenula has very few neurons that decrease activity. These findings suggest that the balance of chemicals controls the processing of negative events and that this processing can be shifted by drugs.
Let’s face it…the brain is complex and we still have so much to learn about it’s structures, chemicals, neural connections and how it all fits together. People with depression process emotional information more negatively than healthy people and show an increased sensitivity to sad faces and a weaker response to happy faces. Medications have been shown to help many people function and feel better, while some cannot tolerate the few groups (there are only 4) of medications available or have found them to be ineffective. More research is being done to shed some light into this regulatory system of the brain and how to treat imbalances.
In the meantime, there are some simple things you can do to feel better…