THE FINAL PAROXYSMAL VISIONS:
A SCIENTIFIC PERSPECTIVE
(c) 2011 Philip T. Nicholson
What happens in the brain when
this sequence of light visions appears?
1. THE WHITE, BULB-SHAPED PROTRUSION
(Note: Keep in mind as you read this material that, in order for a human to see these lights, the same brain mechanisms have to become active—even if the visions are initiated by God.)
The animation of the white, bulb-shaped figure is basically accurate, but the actual vision moves more slowly, has a tip that is more rounded, and has a white, translucent surface that gives it a "hollow" and somewhat "ghostly" look.
This bulb-shaped image is generated by the meditator's selective stimulation of the anterior pole of the hippocampus. The hippocampal pole has virtually the same "thumb-shape" as the white, bulbous figure that the meditator sees "pushing out" of the sky-blue void. As meditators stare at the visual field, their focus of attention stimulates the septum, causing the septum to stimulate the outer layers of the hippocampal pole, which causes the neurons located there to discharge more often than other hippocampal neurons. When the focus of attention drives neurons in the outer layers of the anterior pole to discharge more often than other hippocampal neurons, there is a bright whiteness that appears in the midst of the bright blue background that is being generated by the ongoing hypersynchronous activity. This brighter image mirrors the thumb-shaped contours of the hippocampal pole. The meditator focusing so intently on the visual field (and then on the bulbous figure once it appears) is setting up a positive feedback loop that excites the outer layers of the hippocampal pole. This is clearly an unstable situation.
The bulb-shaped figure does not actually "move" forward; this is an optical illusion. What happens is this: as the meditator's focus of attention gets stronger, there are more discharges in the neurons surrounding the hippocampal pole, and this causes a brightening of the thumb-shaped image. As the image brightens, more of the posterior extension of the hippocampal region that is situated just behind the anterior pole becomes visible, creating the illusion that the bulb-shaped figure has pushed forward. Conversely, if the meditator's attention wanes ever so slightly, neuron discharges in the outer layers of the anterior hippocampus decrease, and the bulbous image dims. In this dimming, the posterior regions of the bulb-shaped figure are first to disappear so that it seems as if the figure is pulling back, receding into the sky-blue background.
2. RISING, MULTIPLYING, AND EXPANDING RAYS
The video animation of the sudden appearance and three-stage transformation of the thin white rays is very realistic.
To explain how the white, bulbous figure can suddenly be transformed into thin white rays, it is important to understand there are 2 types of epileptic seizures: "hypersynchronous seizures" are generated when the inhibitory networks of a vulnerable structure begin to fire rhythmic discharges, but there are also "paroxysmal seizures" which have a different mechanism. In paroxysmal seizures some inhibitory circuits located in a strategic location lose the ability to regulate the neurons they normally target. Those neurons, now released from inhibition and also driven by abnormally high excitation coming from some other source (e.g., from hypersynchronous activity and from the meditator's focus of attention) begin to fire in a rapid, repetitive barrage. The outbreak of paroxysmal firing usually occurs in the hippocampus contralateral to the hippocampus where the hypersynchronous activity originates.
Once there is an outbreak of paroxysmal discharges—in this case, an outbreak in the anterior pole of the hippocampus which appeared as an illuminated "ghost" image in the visual field—the paroxysmal discharges move rapidly through the axons that project from the neurons that fired the first paroxysmal burst to their target neurons in other subfields of the hippocampus. It is reasonable to infer that it is the propagation of these paroxysmal discharges through the interior subfields of the hippocampus that generates the visions of thin white rays evolving in 3 stages. As the paroxysmal discharges enter subfield 1, the initial 3 rays appear; as the discharges move on into subfield 2, the rays double in number and also lengthen; as the discharges move into subfield 3, the 6 long rays spread farther apart as if they were "wilting." After this third and final transformation, there is a delay of 12 seconds before the outbreak of lightning-like flashes. It is reasonable to infer that this delay represents the time required for the paroxysmal discharges to spread out of the hippocampus proper and into the adjacent structures of the temporal lobe, then to spread into the contralateral hemisphere, thereby igniting a bilateral temporal lobe seizure.
3. LIGHTNING FLASHES: THE FINAL VISION
This animation gives a good approximation of the "look and feel" of the paroxysmal vision of lightning-like flashes. The only qualification is that flashes in the actual vision have a dull white color and diffuse, fuzzy borders; there are none of the sharp angular flashes that sometimes materialize in the animation. The actual vision looks exactly like flashes of sheet lightning illuminating a dark storm cloud from within. The paroxysmal flashes in the visual field are accompanied by other paroxysmal symptoms—by loud crackling sounds like an electrical short-circuit; by strong muscle tremors in the face and extremities; by erotic feelings not connected with another person; and by a mixture of emotions, including excitement, euphoria, awe, and fear.
In the actual vision, the lightning-like flashes are confined to one side of the visual field or the other, and the flashes in each side of the visual field occur at unpredictable, seemingly random intervals. As a result, the flashes can seem to alternate, first in one side of the visual field, then in the other, or they can occur simultaneously. This kind of flashing is driven by a pattern that is often found in paroxysmal seizures: large numbers of neurons in the dentate gyrus subfield of each hippocampus discharge "population spikes," then relapse for a brief refractory interval, then fire again.
While this visionary rapture clearly qualifies as a paroxysmal seizure, it is not, strictly speaking, an "epileptic" seizure; this seizure is not the result of defective circuits in the neuron assemblies of the meditator's brain but rather the product of a voluntary choice to induce a rapture and then to prolong it for as long as possible.
- If a paroxysmal seizure breaks out in the hippocampus but does not propagate into adjacent temporal lobe structures, there will be few, if any, symptoms that would be noticed by a person observing the meditator experiencing the seizure.
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