Sizing Up Consciousness by Its Bits

Zimmer, C., (2010). “Sizing Up Consciousness by Its Bits.” Visited on October 3, 2010:

Carl Zimmer’s article “Sizing Up Consciousness by Its Bits” for The New York Times seeks to introduce and explore a relatively new area of research into human consciousness. In interviews with the medical researcher Dr. Giulio Tononi, the article discusses current and past conceptions of consciousness and its’ implications for our interactions with each other and with our environment. Given the importance of consciousness in everyday human life, one would reasonably assume that at this time science would have a detailed understanding of consciousness and how it functions. This is not the case, however. Despite centuries of philosophical debate, medical research, and technological development, humans are largely in the dark, so to speak, about what creates and maintains the spark of consciousness.

In the context of our currently vague understanding, Dr. Tononi’s research proposes a novel way of conceptualizing consciousness. Dr. Tononi’s goal is to apply the theories of informational networks to the human brain, in a method he terms “Integrated Information Theory.” This theory, hereafter referred to as IIT, seeks to understand the human brain as an integrated network of nodes (neurons in this case) that together create consciousness as a product of their cooperation. One of Dr. Tononi’s primary goals with IIT is to calculate a rough value for phi, which represents the total integrated informational capacity of a network. If you suppose a network of just a handful of neurons that can all only be either on or off, then the value of phi for that network would be somewhat low. A human brain, on the other hand, has billions of neurons that can be connected and activated in trillions of different ways. As a result, the human brain’s phi value can only be guessed at currently.

The question, then, is how does IIT relate to medicine as it is practiced today, and what benefits could it possibly offer? One of Dr. Tononi’s recent tests with human subjects may point the way. In the test, subjects had their brainwaves recorded while a small magnetic coil was pulsed on and off near their scalp. The results were striking: the electrical activity in the brain could be traced in direct response to the magnetic pulse, rippling outward in the brain like water disturbed by a dropped stone. In a follow-up test, the subjects were administered a sedative to slow their neural activity and then the magnetic pulses were repeated. As could be expected, the electrical chain reaction from neuron to neuron was significantly slowed. These results and others indicate that it may be possible to establish a “consciousness index,” or a numerical scale on which to judge the consciousness level of a subject’s brain. If IIT is in fact a reliable conceptualization of how consciousness works, then suddenly phi becomes a critical indicator of consciousness in the brain.

At present the practical applications of a consciousness index are somewhat limited. Most importantly, anesthesiologists would find it extremely useful to be able to quantify consciousness; with a “consciousness meter” of sorts, which Dr. Tononi hopes to develop, anesthesiologists could take much of the guesswork and danger out of rendering patients unconscious for surgery. Pharmaceutical companies could use a consciousness meter to determine the exact neural effects of new drugs in clinical trials, without the need for subjective measurements such as questionnaires and interviews. Traumatic brain and spinal injury patients would also be given increased access to more accurate diagnoses, thus allowing doctors to better differentiate between paralysis and comas. It remains to be seen if a quantified theory of consciousness could have other applications beyond the medical profession. Dr. Tononi and his colleagues are still only able to associate general categories of thought with somewhat-defined areas of the brain, but perhaps eventually thought can be traced back to its most basic levels.

  1 comment for “Sizing Up Consciousness by Its Bits

  1. November 8, 2010 at 8:37 pm

    If this works, our mental model of what it means to be conscious will change. Having a rigorous way of measuring consciousness—consciousness meter—will not only change medical practice, it will also change the law.
    Not long ago, people were buried with little brass bells—an insurance policy in case they were not really dead and needed to sound an alarm for assistance. Some coffins were found with scratch marks on the interiors of the lids—a very bad case of cognitive blindness.
    We’ve progressed somewhat, but we still can’t be 100% sure in some grey area cases (think back to Terri Schiavo case a few years back).
    This is a situation where technology can change medical, legal, and social understanding of consciousness.

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