According to Andrew Newberg, the brain's machinery of transcendence is set in motion by a mind willing itself toward the divine. It begins, for example, when a Buddhist dwells on the intention to clear the mind of thoughts, or a Trappist wills the mind to focus fiercely on God. These conscious intentions are translated into neural energy that soon travels in reverberating cycles through the brain.
As meditation or prayer continues, the neural reverberations intensify, until brain activity becomes abnormally high. In response, key regulatory structures in the limbic system, responsible for keeping brain activity on an even keel, would act to calm things down by closing the floodgates on the flow of neural information. This hampering effect--a process Newberg calls "deafferentation"-- would, under certain circumstances, blockade the brain's orientation area, the structure responsible for generating a physical sense of self. The result would be the brain state Newberg captured in the above SPECT scans; a state in which the line between self and the rest of the universe begins to blur, and the experience of mystical union begins.
The baseline image, above left, was taken while the subject was in a normal waking state. It shows a modest amount of activity in the frontal lobes, as shown by some red and some yellow activity at the top of the scan.
The image, above right, was taken while the subject was engaged in deep meditation. The increased activity in the frontal lobes, shown by markedly more red in areas that were yellow in the baseline scan, suggests deep concentration. The meditation scan also shows a corresponding decrease in activity in the parietal lobe in the lower right portion of the scan. That, according to Newberg's theory, suggests a blurring of the line that defines the self.
This machinery of transcendence can be set in motion by other activities that produce rhythmic responses in the brain--ritualized behaviors such as chanting, singing and drumming, for example, seem perfectly suited to triggering it. Since the intensity of rituals are limited, for the most part, by the body's physical endurance, they would produce only partial stages of deafferentation, and much milder spiritual states. Only the tireless energy of a mind striving toward spiritual focus can push the brain to a state it would perceive as Absolute Oneness, or a holy union with God.