FROM – THE BRAIN FROM TOP TO BOTTOM WEBSITE

You can navigate the site from HERE, beginner, intermediate or advanced

PARTS OF THE BRAIN THAT SLOW DOWN OR SPEED UP IN DEPRESSION

“Though depression involves an overall reduction in brain activity, some parts of the brain are more affected than others. In brain-imaging studies using PET scans, depressed people display abnormally low activity in the prefrontal cortex, and more specifically in its lateral, orbitofrontal, and ventromedial regions. And the severity of the depression often correlates with the extent of the decline in activity in the prefrontal cortex.

The prefrontal cortex is known not only to be involved in emotional responses, but also to have numerous connections with other parts of the brain that are responsible for controlling dopamine, norepinephrine, and serotonin, three neurotransmitters that are important in mood regulation. More specifically, the lateral prefrontal cortex seems to help us choose a course of behaviour by letting us assess the various alternatives mentally. The orbitofrontal cortex seems to let us defer certain immediate gratifications and suppress certain emotions in order to obtain greater long-term benefits. And the ventromedial cortex is thought to be one of the sites in the brain where we experience emotions and the meanings of things.

The two halves of the prefrontal cortex also seem to have specialized functions, with the left half being involved in establishing positive feelings and the right half in establishing negative ones. And indeed, in depressed people, it is the left prefrontal cortex that shows the greatest signs of weakness. In other words, when people are depressed, they find it very hard not only to set goals in order to obtain rewards, but also to believe that such goals can be achieved.

In healthy people, the left prefrontal cortex might also help to inhibit the negative emotions generated by limbic structures such as the amygdalae, which show abnormally high activity in depressed patients. In patients who respond positively to antidepressants, this overactivity is reduced. And when the amygdalae remain highly hyperactive despite antidepressant treatment, the likelihood of a patient’s relapsing into depression is high.

It is also interesting to note that when someone’s left prefrontal cortex is operating at full capacity, the levels of glucocorticoids in their blood are generally very low. This follows logically, considering the harmful effects that high levels of glucocorticoids have on mood.

Brain-imaging studies have also shown that in patients with severe depression, the volume of the two hippocampi is reduced. This atrophy may be due to a loss of neurons that is also induced by the toxic effects of the high levels of glucocorticoids associated with recurrent episodes of depression.The extent of atrophy in the hippocampus even seems to be proportional to the sum of the durations of the episodes of depression, and depressions that are treated rapidly do not seem to lead to this reduction in hippocampal volume.”

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I am over on my Taking Care of Mothers blog working on my ABUSIVE BORDERLINE MOTHER BRAIN book/information.  You can check out the progress (long way to go yet) here:  +BOOK ON BORDERLINE BRAIN

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Yet another really cool brain site — stuff we should learn in grade school:

Brain structures glossary

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