INTEGRAL WORLD: EXPLORING THEORIES OF EVERYTHING
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Andrea Diem-LaneAndrea Diem-Lane is a tenured Professor of Philosophy at Mt. San Antonio College, where she has been teaching since 1991. Professor Diem has published several scholarly books and articles, including The Gnostic Mystery and When Gods Decay. She is married to Dr. David Lane, with whom she has two children, Shaun-Michael and Kelly-Joseph.


THE METABOLIC THRESHOLD

Consciousness and Energetic States

Andrea Diem-Lane

A Preview Essay

Consciousness, ironically, is a physics problem curled up in chemical and biological and psychological garb.

That consciousness is the result of underlying biochemical processes seems to be an obvious fact, especially given our respective sleep cycles. Moreover, each of us are too acutely aware of how a slight modification in our diet can alter how we feel and how we navigate throughout the day. Add a couple of strong alcoholic drinks into the mix and the world around us swirls in quite a different fashion.

Recently, a new study was completed which indicated a critical metabolic threshold within the brain for the emergence of consciousness. As reported by The Scientist, which summarized the findings:

“Differentiating states of consciousness in brain-injured patients is a major challenge for clinicians. Researchers from the University of Copenhagen, Denmark, and their colleagues recently used positron emission tomography (PET) to measure the metabolism of glucose in the brains of 131 patients, finding that 42 percent of normal cortical function is the minimum amount of energy required for conscious awareness. The findings provide 'a simple and objective metabolic marker' of consciousness, the authors wrote in their study, published today (May 26) in Current Biology.”

The idea of quantifying self-awareness via biochemical responses doesn't mean that we have “understood” consciousness as such. But it does provide us with part of the necessary scaffolding underlying how such awareness emerges. As the study indicated, “regional differences in glucose metabolism (relative to whole-brain metabolism) correlated with the patients' likelihood of regaining certain cognitive functions, such as vision and language comprehension.”

What makes this study particularly powerful, of course, is its predictive quality, such that “In nearly all cases, whole- brain energy turnover directly predicted either the current level of awareness or its subsequent recovery,” Kupers said in a statement. “In short, our findings indicate that there is a minimal energetic requirement for sustained consciousness to arise after brain injury.”

This study in particular casts a dark shadow on those who believe that consciousness is divorced from its material substrates since without minimum neural activity (42 percent or above cortical activity being a baseline of threshold) self-awareness apparently doesn't arise.

I don't think this is very surprising, given what we already know about how adenosine works within the brain. As the McGill website on brain function lucidly explains,

“The onset of sleep is triggered not only by your body's biological clock, which regulates the cyclical secretion of hormones determining the best time to go to sleep, but also by the cumulative effect of hypnogenic molecules that build up in the body while you are awake. The molecule adenosine has a number of characteristics that make it an ideal candidate to act as one of these hypnogenic substances: its concentration in the brain is higher during waking periods than during sleep and increases during extended periods of wakefulness; moreover, administering adenosine or its agonists to experimental subjects makes them sleepy. Adenosine is produced by the degradation of adenosine triphosphate (ATP), the molecule that serves as the “energy currency” for the body's various cellular functions. The amount of adenosine produced in the brain thus reflects the activity level of its neurons and glial cells. The brain's intense activity during periods of wakefulness consumes large amounts of ATP and hence causes adenosine to accumulate. The accumulation of adenosine during waking periods is thus associated with the depletion of the ATP reserves stored as glycogen in the brain. The increased adenosine levels trigger non-REM sleep, during which the brain is less active, thus placing it in a recovery phase that is absolutely essential—among other things, to let it rebuild its stores of glycogen. Because adenosine is continuously metabolized by the enzyme adenosine desaminase, the decline in adenosine production during sleep quickly causes a general decline in adenosine concentrations in the brain, eventually producing conditions more favourable to awakening.”

Put another way, if consciousness was indeed distinct from the bodily apparatus that houses it, why would such tiny molecules play such an elemental part in its display? The tired (and not altogether convincing) argument that the brain is a receiving station similar to a television set in one's home doesn't actually resolve the issue of how consciousness emerges but only avoids the query by shifting its central locus. And in so doing it, neglects the very obvious point that in either case (whether awareness is an emergent property of the brain or rather akin to an electromagnetic wave from afar) consciousness is physically related to some measure.

Galen Strawson, writing for the New York Times, captures the essence of the problem of self-awareness in the very title of his essay: “Consciousness isn't a Mystery. It's Matter.” Of course, saying this doesn't then mean we have solved the conundrum, but only that the real issue at hand is more profound than we might at first suspect: the difficulty in understanding consciousness isn't what it is “like” to be aware (that we already have in abundance, since it is the one thing we experience from the inside out), but rather how physics can explain the material structure that gives rise to such a complex and holistic phenomenon in the first place.

In other words, the following pun (in a precise questioning form) is a literal one: “If we are just matter, what then is the matter?”

Consciousness, ironically, is a physics problem curled up in chemical and biological and psychological garb. We need to undress awareness and understand its primary and core constituents, without which it forever hides its manifold allurements. Analogously awareness is similar to the user interface on our smart phones, which depend upon the hardware and software components of its operating system. To understand the visual and auditory display on your phone, one has to first explore the physical housing upon which it is built. Consciousness without a display is likened here to a movie without a projector or a screen. While some may believe that consciousness will exist without a physical substrate, the evidence suggests otherwise since self-awareness is physics incarnated. Thus, the real mystery that needs to be unraveled concerns matter itself. What is it ultimately?



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