I am all fascinated with the brain, sometimes I look at my brain as my best friend and on other days … not so much. I’ve learned about the brain in school but the course I took (neuropsychology) was more general knowledge. These days I am really interested in the topic of depression. I pair my knowledge (honestly, I need to dust off my knowledge from 15 years ago!) with research I find online. I am not a scientist though. I hope you’ll enjoy my findings and don’t hesitate to leave your comments below!
What do we think, know and how we medicate the brain with depression.
Popular lore has it that emotions reside in the heart. Of course, all things beautiful are in the heart, love, joy, peace … Science, though, tracks the seat of your emotions to the brain that regulates mood. Researchers believe that — more important than levels of specific brain chemicals — nerve cell connections, nerve cell growth, and the functioning of nerve circuits have a major impact on depression. Still, the understanding of the neurological setup of mood is incomplete.
Areas that play a significant role in depression are the amygdala, the thalamus, and the hippocampus. Imagine the general function of those regions being influenced by depression or vice versa.
The amygdala is part of the limbic system, that is associated with emotions such as anger, pleasure, sorrow, fear, and sexual arousal. The amygdala is activated when a person recalls emotionally charged memories, such as a frightening situation. Activity in the amygdala is higher when a person is sad or clinically depressed. This increased activity continues even after recovery from depression.
The thalamus receives most sensory information and passes it on to the cerebral cortex, which directs speech, behavioral reactions, movement, thinking, and learning. Some research supports the link of sensory input to pleasant and unpleasant feelings.
The hippocampus is part of the limbic system and has a central role in processing long-term memory and recollection. Interplay between the hippocampus and the amygdala may be illustrated as “once bitten, twice shy.” It is this part of the brain that registers fear when you are confronted by a barking, aggressive dog, and the memory of such an experience may make you afraid of dogs later on. This will be important later on, when I’ll discus the effect of depression on memory and how those two interact.
Research shows that the hippocampus may be smaller in people who experienced depression. The more bouts of depression, the smaller the hippocampus. Stress, which plays a role in depression, may be a key factor here, since experts believe stress can suppress the production of new neurons (nerve cells) in the hippocampus.
Research suggests that ongoing exposure to stress hormones impairs the growth of nerve cells in the hippocampus.
What does this have to do with medication?
Researchers are exploring possible links between sluggish production of new neurons in the hippocampus and low moods. The answer may be that mood only improves as nerves grow and form new connections, a process that takes weeks. In fact, animal studies have shown that antidepressants do spur the growth and enhanced branching of nerve cells in the hippocampus.
So, the theory holds, the real value of these medications may be in generating new neurons (a process called neurogenesis), strengthening nerve cell connections, and improving the exchange of information between nerve circuits. If that’s the case, depression medications could be developed that specifically promote neurogenesis, with the hope that patients would see quicker results than with current treatments.
What about the dopamine and serotonin? And genes? Aren’t there genes involved in the process? All of those will be covered in this small, pleasant series. If you’re a curious person and you want to know more about depression and the brain, you’re very welcome to keep reading and discovering with me.
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