Interoverted brains function differently than Extroverted

A friend sent me these:

http://introvertdear.com/2015/03/04/introverts-and-extroverts-brains-really-are-different-according-to-science/

http://introvertdear.com/2015/07/14/introverts-alone-time-science-marti-olsen-laney/

My response to these articles:

I wonder how HSP introverts are different then from introverts who are not; those articles seem to describe HSP brain function especially--both introverts and extroverts who are HSP.

The extroverted HSP must function very differently from all other groups having elements of both extroverts and introverts physiologically. They need downtime too or suffer the same consequences.

The publisher of these articles doesn't seem to differentiate between introverts and HSP, and the two groups are not the same. Still, this is interesting.

Essentially, I'd like to know if they screened for HSP traits or not to differentiate the results. My guess is if they had, their results would be far more precise and interesting. Without knowing the sample base the research was done on, there is no way of knowing if it was mostly HSP or not or a mix.