I'm now dealing with PCS, and I noticed that with good sleep and very low stress levels, my symptoms become much milder and I just feel OK.

But a little bit of stress, I noticed, will cause my symptoms to return and make my life harder for a few days (just a little bit of stress messes me up, sometimes for a few days). Without stress, I'm feeling 80%-90% of what I was before my mTBI (which was 2 months ago). Although that sounds good, if you put me in a slightly stressful situation for a minute or two, I'll feel 20%-30% of what I was before my mTBI, and I'll most likely stay with that feeling for a few days. And by stress, I don't mean something necessarily extreme - it could just be an argument with someone.

Is it known exactly why the concussed brain has intolerance for stress especially early in the recovery process? I mean, is there an explanation for what parts of the brain that are responsible for stress tolerance are functioniong more weakly after a concussion?

By the way, I'm learning neuroscience, pharmacology and biology at my free time, so I have some understanding in these areas.
As a part of my learning, I would like to understand the causes to the extreme sensitivity of the concussed brain to stressful situations.

Does anybody here know and can please give a detailed explanation about these stress tolerance mechanisms?

Thanks,
-ProAgonist