depression resulting in chemical imbalance?
Scientists believe that manoamines-mood-related chemicals such as serotonin, norepinephrine and dopamine are low in the brain in people with major depression. This is commonly referred to as a "chemical imbalance." Until now, no one had ever found an explanation for monamine loss. Click on the bottom below to read an article on the monamine loss explanation.
Thalamus: The thalamus is another part of the brain that controls emotion. In people with depression, the thalamus becomes larger. Studies show that people with major depressive disorder (MDD) showed a 31% greater than average of nerve cells in the portion of the thalamus involved with emotional regulation.
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Amygdala: The amygdala is an almond-shape set of neurons that forms part of the limbic system. This part of the brain plays a key role in processing emotions and is linked to both fear responses and pleasure. The amygdala becomes overactive when you have depression.
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symptoms of depression and the part of the brain that connects to it:
Persistent sadness or low mood- The shrunken ventromedial cortex
The feeling of self hatred, worthlessness, hopelessness, loneliness ect.- The shrunken ventromedial cortex
Angry outbursts, thoughts of suicide, thoughts of self-harm- Destruction of the prefrontal cortex
The feeling of self hatred, worthlessness, hopelessness, loneliness ect.- The shrunken ventromedial cortex
Angry outbursts, thoughts of suicide, thoughts of self-harm- Destruction of the prefrontal cortex
There are different regions of the prefrontal cortex that are affected by depression..." |
4 regions of the prefrontal cortex that connect to depression: the orbitofrontal cortex, anterior cingulate cortex, the ventromedial cortex, and the limbic system. All of these regions are changed by depression and below, I`ll explain what the purpose/task of these regions are and how they are affected by clinical depression.
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The orbitofrontal cortex (OFC) : The OFC enables individuals to adapt their behavior in response to unexpected rewards or adversities. In people with depression, the OFC is almost nonexistent and it's volume is reduced.
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The anterior cingulate cortex (ACC) :
The cingulate cortex is responsible for emotional sensations such as fear, anxiety or pleasure and the associated physical responses to those emotions. In people with depression, this part of the brain becomes more active. |
The ventromedial cortex (vmPFC) : The ventromedial cortex is heavily involved in feelings of pleasure and positive reinforcement. A depressed brain's vmPFC get's 40% smaller than a not depressed brain.
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The limbic system: The limbic system has a lot to do with the formation of memories and responsible for our emotional life. In people with depression, the limbic system has had a disruption or overactivation.
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The term mental illness clearly indicates that there is a problem in the brain." |
Studies on the brain activity in depressed people show an overall pattern: A general decline in activity in the brain cortex (especially in the prefrontal cortex), with increased activity in the brains limbic structures.
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A despressed brain also has decreased emotional memory, impaired brain plasticity, and a smaller hippocampus. Studies show abnormalities in the glutamatergic system, but no one really knows how that relates to the brain and to depression systems.
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Depression & the brain |
Depression & the brain |