Last year I had taken an intro-level class on the physiology of the human brain at the Stanford Center for Continuing Studies. This is a survey paper from that class.
BTW, here is an excellent blog post on some relevant goings on related to meditation in and around the SF Bay area.
Idle Thoughts 
COMPREHENSIVE VIEW OF SCIENCE OF RELIGION (THEOLOGY)
A Scientific Understanding of Meditation and Yoga
In Bhagavad-Gita Lord SriKrishna says to Arjun:
“I taught this immortal Yoga to Vivasvan (sun-god), Vivasvan conveyed it to Manu(his son), and Manu imparted it to (his son) Iksvaku. Thus transmitted to succession from father to son, Arjun, this Yoga remained known to the Rajarisis (royal sages). It has however long since disappeared from this earth. The same ancient Yoga has this day been imparted to you by Me, because you are My devotee and friend, and also because this is a supreme secret”.
Yoga (Application) which was based on the control of the body physically and implied that a perfect control over the body and the senses led to knowledge of the ultimate reality. A detailed anatomical knowledge of the human body was necessary to the advancement of yoga and therefore those practising yoga had to keep in touch with medical knowledge. (Romila Thapar, A History of India, volume one).
I suggest : Mind and brain are two distinct things. Brain is anatomical entity whereas mind is functional entity. Mind can be defined as the function of autonomic nervous system (ANS). It is claimed that mind can be brought under conscious control through the practice of meditation. But how? ANS is largely under hypothalamic control which is situated very close to optic chiasma (sixth chakra or ajna chakra). Protracted practice of concentration to meditate at this region brings functions of ANS say mind under one’s conscious control.
Although Danah Zohar has coined the term Spiritual Quotient for the first time but she did not establish any mathematical relationship for this. Without establishing mathematical relationship spiritual intelligence can not be termed as spiritual quotient.
Deepak Chopra has given a formula of spiritual quotient in terms of Deed (D) and Ego (E). According to Deepak Chopra S.Q.=D/E. According to him if E is ‘zero’ the S.Q. will be infinite. This appears to be very fascinating but it is highly abstract which can not be measured experimentally accurately and precisely. However, this formula has immense value to understand S.Q.
I have also discovered a mathematical relationship for S.Q about eight years back in 2001. I have used physiological parameters which can be measured accurately and precisely and can be tested and verified experimentally. According to this formula S.Q. can be expressed as the ratio of parasympathetic dominance (P.D.) to sympathetic dominance (S.D.). Parasympathetic nervous system (PSNS) and sympathetic nervous system (SNS) are the two parts of the autonomic nervous system (ANS) which is largely under hypothalamic control. Hypothalamus is situated very close to the Sixth Chakra. During practice of meditation at Sixth Chakra these centres are galvanized which has very positive effect on practitioners spiritual, emotional, psychological and physical well being.
According to this relationship spiritual quotient can be written as:
S.Q. = P.D./S.D.
If the value of S.Q. comes >1 (greater than one), it can be assumed that the person is moving towards self-realisation and if the value of S.Q. comes <1 (smaller than one) it can be predicted that the person is living under stress.
This formula can be tested and verified experimentally.