Stimulus/Response

Deciding to explore the use of another form of stimulus has opened up a wonderful new playground for mental modelling.

Our sensitivity to light and sound is pretty well understood. We’re equipped with fully functional light and sound sensitive devices as standard. When we expose our eyes or our ears to a stimulus, the pathways to the sensory cortices have been well mapped. The electrochemical behaviour of every cell/neuron along the way has been observed and documented. There’s no shortage of well confirmed descriptive knowledge of the brain and the standard senses.

Using audiovisual stimulation we’re relying on the fact that the stimulus will faithfully appear at the appropriate sensory cortex, where it will be subjected to a yet poorly understood autonomous filtering and reconstruction process, before being presented to various elements of the consciousness for labelling and judgement. For all that is known about the brain, the emergent properties thereof remain largely subject to conjecture.

In the not too distant future I’ll be donning a helmet with a number of solenoid coils aimed at the centre of my cranium. Each of them will be capable of delivering anything up to and well beyond the 10 milliGauss that is considered ‘safe’ for weak-field electromagnetic stimulation. Taking all that I have read about and by Persinger, Koren and Murphy, plus what I’ve managed to piece together about the brain from other sources, what do I know?

It fun really. When I stuck my snout into AVS/brainwave entrainment I was initially desperate, then relieved, and then curious. My curiosity led me to a point where I was highly skeptical of the theory behind entrainment. Burrowing around a bit more, I have satisfied myself that the small-scale, variably controlled clinical trials represent ample evidence that AVS is a statistically significant contributor to positive outcomes in the treatment of numerous conditions. At the other end of the system, I’m amply satisfied that there are sufficient measurable effects at the neural level to promise full explanation of the effectiveness of AVS. Between these areas of certainty lies a whole swampful of dubious information. For myself, I’m content as long as I’m not expected to believe in any secret frequencies, proprietary waveforms, or convoluted attempts to explain the effectiveness of AVS in terms of pure entrainment.

As far as I know, the human body does not come standard with magnetic field sensors. Sure, we are affected by fields of varying frequencies in a variety of ways, but we are not equipped to be consciously aware of low frequency electromagnetic signals. While sound and light enter by approved channels, a magnetic field is bypassing the very structure intended to protect the brain from outside influence.

Regardless of what might be said on the Shakti Technology about what is and what is not electromagnetic stimulus, the Shakti uses electromagnetic stimulus. There’s invitation to experiment with simple waveforms, but the headline sessions feature renditions of signature EEG patterns from various parts of the brain. There’s a black hole where information on signature EEG patterns should be.

At this precise moment I’m satisfied that magnetic stimulation is safe, therapeutically useful, and a prime cause in a variety of extra-ordinary experiences. I’ve got a rough model of how I think magnetic fields effect neural processing – a hypothesis that makes sense to me. Everything in between, 90% of the promotional blurb, remains suspect.

I’ve got a good feeling about weak-field transcranial magnetic stimulation. If the mechanism is as I believe it to be, very specific stimulus/response should be achievable. I’m going in on the basis that a changing magnetic field will induce current in axons that cross the field. These currents will be much smaller than the action potential itself, but they will, I believe, slow transmission. I’m expecting this to inhibit neural input from the chosen region.

Using the same techniques of practical skepticism, CES (cranial electrostimulation) doesn’t fare as well. The clinical results are what they are – there’s good, but not conclusive, evidence that CES is therapeutically useful. The theory behind it makes not the slightest sense to me. The best I can make of it is that the electric impulses act on the sense of touch, evoking a neural response in much the same way as sound or light does. The electrical path from ear to ear is decidedly short of obvious targets, with most of the current passing through the tissues external to the skull, so I’m better satisfied with a tactile explanation.

I hope you don’t mind me thinking aloud.

Cheers,
Craig

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