Posted by Pfinstegg on April 8, 2003, at 21:04:00
In reply to Re: Cortisol , posted by Dave1 on April 8, 2003, at 20:11:52
It's my understanding that all the changes which occur in a hippocampus damaged by stress hormones are potentially reversible, because that particular part of the brain has so much plasticity. According to what I have read, the damage includes:
1. A stopping of the daily birth of new neurons in the CA-3 region. We are supposed to produce several thousand new neurons each day, and some neuroscientists think that just not producing these may result in depression.
2. Loss (death) of neurons which secrete and take up serotonin, nor-epinephrine, dopamine and maybe even cortisol itself (uptake only for that one). The neurons which survive have shortened dendrites, which probably means that they are not doing a normal amount of secreting or taking-up.
3. In terms of what can be seen on scans, an MRI often shows a small left hippocampus- up to 20% smaller- and a SPECT scan often shows decreased glucose uptake on the left side, meaning that the blood flow is decreased- a hallmark sign of depression.
Since the wonderful finding a few years ago that the hippocampus is really a self-renewing organ, and can probably overcome the terrible things cortisol does to it if we can just get it our adrenals to secrete it on a normal, as-needed basis, it's very understandable that some of the best neuroscientists in the world are focussing on that very thing.
Pfinstegg
PS I know you didn't ask me this question, but I just answered anyway! I very much hope that jrbecker will also answer, as his posts and references have been wonderful.
poster:Pfinstegg
thread:215282
URL: http://www.dr-bob.org/babble/20030407/msgs/217583.html