What first grabbed my attention is the discovery that introversion is physiological (as opposed to shyness, which is behavioral). Extroverts and introverts actually use different neurotransmitters and different neural pathways to the brain. Introverts' dominant neurotransmitter, acetylcholine, is associated with the energy-conserving parasympathetic nervous systems and with moving memories into long-term storage. Because introverts operate heavily in long-term memory, when speaking we tend to pause or speak more slowly than most extroverts are comfortable with. I can certainly relate to this, as I'm sure anyone who's spoken with me much would agree.
I clearly use to exhibit:
•Reduce eye contact when speaking to focus on collecting words.
•Start talking in the middle of a thought.
•Have a good memory but take a long time to retrieve memories.
•Can forget things they know well — might stumble around when explaining their job or temporarily forget a word they want to use.
•May think they told you something when they just have thought it.
•Rehearse things before speaking (even for casual conversation).
•May not be aware of their thoughts unless they write or talk about them.
•Clearer about ideas, thoughts, and feelings after sleeping on them.
•Immerse themselves thoroughly in a very few subjects.
Acetylcholine is one of the major neurotransmitters and requires choline for its synthesis. Adequate acetylcholine levels in the brain are believed to be protective against certain types of dementia, including Alzheimer's disease. Human studies are needed to determine whether dietary choline might be useful in the prevention of dementia.