The Deepest Memories

Considering how much fun can be had with them, brainwaves get surprisingly little coverage in standard texts. After presenting several propositions concerning the purpose of brainwaves, Messrs Bear, Connors and Paradiso conclude, in their 2001 edition, Neuroscience: Exploring the Brain, as follows:

 “For now, the functions of rhythms in the cerebral cortex are largely a mystery. One plausible hypothesis is that most rhythms have no direct function. Instead they may be intriguing but unimportant by-products of the tendency for brain circuits to be strongly interconnected, with various forms of excitatory feedback. When something excites itself, whether it is an audio amplifier or the human stadium wave, it often leads to instability or oscillation. Feedback circuits are essential for the cortex to do all the marvelous things it does for us. Oscillations may be the unfortunate but unavoidable consequence, unwanted but tolerated by necessity. Even without a function, EEG rhythms provide us with a convenient window on the functional states of the brain.”

There’s a few propositions that have the brain rhythms providing clocks for various types of brain function. The computer you’re now using uses a number of clocks to control the timing of the various processes – maybe a 2.2GHz CPU core, 800MHz system bus, 1400MHz GPU shader and so on. Although it is a mistake to draw direct comparisons between a digital computer and the as yet poorly described architecture of a brain, it is not unreasonable to think that there would be occasions where one cortical process has to wait for another process underway at a distant location.

My experiences ferreting around in my own memory whilst under the influence of AVS point to an inverse correlation between the dominant frequency and the depth or obscurity of memory accessed.

Let’s start with delta. Usually associated with dreamless sleep (delta dreaming does occur occasionally in most people), fancifully, I think, targeted for “deep meditation”, delta is assigned to the frequency range 0-4.0Hz. Through many experiments with catnap lucid dreaming, I’ve found that the part of the dream that I don’t remember clearly, the part before it “becomes lucid” occurs whilst in delta sleep. If I can piece together the “thoughts” that inspired the dream, I’ll often find that it’s something I haven’t thought about in ages, but that is quite pertinent to the present. I regularly use sessions consisting of extended periods of delta with periodic peaks into theta, alpha, beta and gamma to dig up old memories.

Theta is the 4.0-7.0Hz range (it’s not really proper to use the point-zero, because the ranges are arbitrary and different sources use different figures, but it looks better). Theta is associated with rem/dreaming sleep and with creative thinking. When I spend time contemplating in theta, I find all sorts of things that I normally wouldn’t think of together arising in a manner that makes it easy to see new correlations.

Alpha covers 7.0-12.0Hz and it’s our relaxed-awake state. Normally when we remember a dream it is because remnants of it remained accessible as we shifted into alpha, and we are able to work backwards with the sparse details available on waking. Thinking over immediate issues whilst maintaining dominant alpha is superb. With all the defensive mechanisms suppressed it becomes possible to avoid circular thinking, fatalistic thinking and irrational fears/insecurities. Contemplation/meditation, call it what you will – alpha seems to allow calm review and integration of recent events, and relatively unclouded projection into the near future.

Beta, 12.0Hz and beyond (arguably to 25.0Hz where gamma may be said to begin), is our state of engaged consciousness. If the body is even somewhat engaged in an activity, the normal (?) brain will be displaying increased beta. The very act of opening eyes suppresses alpha in favour of the alert beta. Everything about the behaviours associated with beta, and the symptoms of beta deficiencies, points to it being the frequency range in which we deal with the here and now.

Gamma is a tricky one to discuss. It’s being attributed with all sorts of ultra-spiritual or mega-brilliant implications, but I haven’t been able to associate any characteristic sensations with gamma-range AVS. It’s hard to measure too – much lower amplitude than any of the other bands, and only its lower frequencies can be recorded with the Pendant EEG. I like the proposition that theta and gamma are involved in cognitive binding (linking new things with old things to form memories). I’ve written a few sessions exploring this idea – ThetaGamma in Freebies, for instance.

Taking the characteristic experiences of each band, it seems to me that it is the wavelength, rather than the frequency, that may be of interest, that maybe the dominant frequency is indicative of the communication time from the cortex to the brain structures involved in that type of memory/thought. It’s already well recognised that there are several levels of memory – working, short-term and long-term in the simplest form. It seems reasonable to assume that fast, real-time processes will have to deal with data readily accessible – probably integral to or close to the cortex. As a memory becomes more persistent, it will involve deeper and deeper structures.

Whether this represents a correct understanding of the function of brain rhythms in memory or not, it is a useful way to think about AVS session frequencies. Enhancing brain activity at frequencies known to be associated with a particular activity or mode of thought often results in immediate improvement in performance. Working with a model of layered memory, and using AVS to “tune-in” a layer, has been valuable to me in my own therapeutic endeavours, a species of cognitive behavioural therapy.

If anyone has personal stories to support (or refute) this model, I’d love to hear them.


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  • Mark  On November 17, 2009 at 8:03 pm

    That was a really interesting impression you’ve given off what what the various brainwave frequencies mean for you and a very original interpretation of why it is you respond to AVS stimulation . This is just what it is needed , some fresh intuition and theoretical interpretation of the mechanisms and outcomes of achieving various dominant brainwave states beyond the commercial hyperbole that is delivered in the interests of selling AVS.

    I am in complete agreement that it is the unfettered contemplation and thought processes accessable in these states that at least for me is the value rather than trying to achieve the ‘states’ that the textbooks say I should be experiencing.

  • CraigT  On November 18, 2009 at 6:31 am

    Hi Mark,
    Thanks for your thoughts. I am definitely an advocate of “active” AVS – full participation and the invocation of intent. Passive AVS is nice and I love just laying back and enjoying, but it’s when I fully engage with the process that the real benefits arise. Of course, to engage with the process you have to have some sort of understanding of how it works – in a field where facts are scarce, it matters little whether the understanding is ultimately correct, only that it is consistent with observable reality, it predicts certain outcomes and it’s repeatable. The multilayer model currently meets these criteria. I would have no hesitation in adopting or integrating another model if it provided a better description.
    I should also add that “unfettered” is a scary thing for a lot of people – letting the “ghosts” out if you’re unprepared to deal with them can be problematic. When using AVS to deal with deep issues it pays to ensure you’ve got good support at hand.

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