To summarize (and probably oversimplify) Fred's research: Samadhi is where a healthy brain is not doing anything, but is still alert. In more detail, during PC during TM, the connectivity of the default mode network (the part of the brain that activates when you're not trying to DO something) becomes very enhanced, while the "doing" aspect of the activity of the brain becomes less.
This has the effect of enhancing connectivity between the parts of the brain that have to do with "sense of self." Along with this, the person's reaction to stressful situations becomes less intense. Outside of meditation, as these connections become stronger, the meditator starts to notice the emergence of a strong, uninvolved sense of self. As these connections become even stronger, the sense of self becomes permanent in the sense that it is present at all times, whether waking, dreaming or sleeping. By this point, one no longer sees temporary things like beliefs and emotions as being the "true" self. Along with this, the person's reaction to stressful situations becomes less intense. As the connections become even stronger, the person's reaction to stressful situations becomes less intense. Rinse and repeat. GC and UC seem to be enhancements of this situation but don't just involve connections within the frontal lobes, but with the rest of the brain as well. In UC, I'm guessing, not only are the connections very strong bertween the frontal lobes (sense of self) and the rest of the brain, but the "doing" aspect of electrical activity of the brain has become very much a harmonic sitting on top of the "sense of self" lower alpha frequencies. In a very real, physical, measurable, sense, all perception and activity are now harmonic fluctuations of the "sense of self" highly coherent alpha EEG. Everything is simply fluctuations of Self, as MMY says. L ---In FairfieldLife@yahoogroups.com, <fleetwood_macncheese@...> wrote : There does appear to be a physiological correlate to Samahdi, and the permanent witnessing, though it must be more comprehensive than anything western medicine recognizes, because the effect perpetuates, in an unaltered state, no matter what the relative awareness is doing. There are other side effects, too, as I seem to be getting *younger*, and stronger, as the years go by. Several people have remarked on the difference. ---In FairfieldLife@yahoogroups.com, <seerdope@...> wrote : Mac said: "Just as it says in the Gita, about pure consciousness being unable to be influenced or destroyed, yes, the witness of pure awareness, continues, through any permutation of awareness the mind is in - sleep, dreaming, intoxicated, awake...." "BINGO!!! Yes, it is our eternal self, that lives beyond time and space." What is the role of the brain in Samadhi and higher states? Sparaig recently quoted MMY: "Every experience has its level of physiology, and so unbounded awareness has its own level of physiology which can be measured. … Everything is physical. Consciousness is the product of the functioning of the brain." This implies or opens the door to a model that Samadhi and higher states are achieved via neuroplasticity of the brain -- "culturing" and "refining" it in ways as to enable Samadhi, eventually on permanent basis. That is, the brain is "optimized" via new neural connections, long-term potentiation (persistent increase in synaptic strength following high-frequency stimulation of a chemical synapse) across existing neural pathways, changes in activation potential of long cascades of neurons, modification of mix, availability and persistence of neurotransmitters (NT), changes in NT receptors, etc. Which is a fascinating prospect. And might imply a genetic propensity towards Samadhi in some populations or families relative to others. That is, while everyone could culture Samadhi via systematic neuroplasticity methods, some may have a genetic head start -- the brain is already has some requisite pre-wiring. However, if Samadhi is brain dependent, then established Samadhi would not be sustained upon death of the body. And may not persevere with large changes to brain chemistry or structural changes from accidents or disease such as Alzheimers. And cessation of Samadhi at death would be inconsistent with significant portions of traditional literature, which in turn would then tend to place all statements in traditional literature in question. On the other hand, if Samadhi is not brain dependent, then what are physiological / brain research on meditation / yoga measuring? And why would the body or brain matter in modalities to culture Samadhi? These questions keep me awake at night.