It is more than amply made clear in our scriptures that the external characteristics of a Jivanmukta are indistinguishable from those of any ordinary person. Still we can glean from several of the texts subtly identifiable markers. All the markers may not be present in every Jivanmukta.
Some of the traits may arise only in a Jivanmukta in the last stages of the Seven Step Knowledge Path. As this is only a coarse level attempt, it may not be wise to demarcate the specifically identifiable characteristics in each stage of the Seven Step Path. Tradition does list the specific pointers of each of these Steps; but those pointers are said to be useful for self-assessment rather than evaluation by an external agent.
The neuronal correlates of some of the characteristics can be in the brain chemistry reflected through hormonal changes detectable in blood. Some other traits can be seen only from the relative activity of a specific lobe of the cortex (outer most layer of the brain) or a deeper part of the brain detectable through a suitable imaging technology. Leaving out the details for the present, I shall tabulate below the characteristics that can serve as possible markers for a Jivanmukta.
1. Universal “Love” or (Maitri)
Possible Indicator detectable in blood:
High levels of Oxytocin
2. Equipoise
Possible Indicator detectable in blood:
High levels of Serotonin
3. Tranquility
Possible Indicator detectable in blood:
High levels of Serotonin, Low corticosteroids,
low Norepinehhrine
4. Sense of happiness
Possible Indicator detectable in Imaging:
Squirts of dopamine from the Ventral Tegmental area to cortical and other areas produce happy feeling. Activity in Prefrontal Cortex, Insula etc. depend on an external agent for stimulation in an ordinary person to generate the feel of happiness. The ‘Ever Happy’ feeling in a Jivanmukta could be governed by a different neural circuit.
5. Absence of sense of ‘self’
Possible Indicator detectable in Imaging:
A sense of ‘self’ possibly emanates from activity in medial pre-Frotnal Cortex, precuneus, (responsible for autobiographical memories). Recent research showed that Lower activity in right Parietal cortex is linked to a lesser sense of ‘self’.
6. Absence of “Doership”
Possible Indicator detectable in Imaging:
Consciousness of decision for taking an action takes place much later than ‘brain’ initiating an ‘action potential.’ Latest research shows that the Brain initiates an action by as much as 10 secs before we are consciously aware of deciding to act!
7. Gamma activity in brain
Possible Indicator detectable in EEG:
Gamma activity in meditators and non-meditators differs significantly. We may expect a different range in Jivanmukta.
8. State of Deep Sleep with Awareness
Possible Indicator detectable in EEG:
Deep Sleep is characterized by slow brain waves in the EEG. Activity in the brain during Deep Sleep happens to be in a very few isolated islands of brain as per the work of Dr. G. Tunoni reported recently. Sensory information from external worlds is not received as sensory cortex is inactive (asleep). Therefore, ordinary persons will be unaware of the world during sleep. Because of the fact that a Jivanmukta appears to be in Deep Sleep and also has awareness, we must be able to notice slow wave activity with sensory cortex working in a Jivanmukta, though further downstream processing of the signals in the brain may not be present. Promises to be good marker.
The markers are indicative only. Qualitative base level information for each of the markers have to be established for a normal person from a review of the available published research documents. When once the bench mark levels are agreed to, we may measure the same parameters in any of the volunteering individuals who are known to be those in whom the separate sense of ‘self’ has already collapsed.
Possible extension of the research can then be planned if we are succesful in unequivocally identifying markers in a Jivanmukta.
Also please see: http://www.nondualitymagazine.org/nonduality_magazine.4.jivanmuktarevised_27_apr_2011.htm
Added on 19 Feb 2013:
From p: 80, "Atoms and Eden - Conversations on Religion and Science" by Steve Paulson, OUP, 2010, pp: 312
Steve Paulson: Would you like to speculate here? Suppose you could somehow record what the medieval mystics like Meister Eckhart or St. Francis talked about - these truly big, profound experiences? What's yor guess as to what happened in their brains when they had those experiences?
Dr. Andrew Newberg: I think the orientation part of the brain would be profoundly affected. So while we're seeing decreased activity in this orientation part of the brain during prayer, for example, I think if somebody had a true mystical experience, we would see a vastly greater change - to the point where there would be a complete loss of their sense of self in relation to the world. Now, one other aspect of the overall function of the brain that we haven't mentioned is the autonomic nervous system that regulates our arousal and our quiescent responses in the body. What we have hypothesized is that in these peak states, there is a simultaneous activation of this very profound sense of arousal and alertness and also a deep sense of oceanic bliss and calmness. Maybe someday, if we're fortunate enough, that could actually be captured on a brain scan.
(Dr. Newberg's latest research paper can be seen at: http://beyond-advaita.blogspot.com/2012/11/brain-activity-during-trance-state.html ).