Lab Talk


Getting at Consciousness

The nature of consciousness is difficult to understand but that doesn’t mean we can’t learn to manipulate it.

Consciousness is the most elusive aspect of the human mind. What is it and why is it even there? Other than our subjective experience of it, there is no other way to define it. Doesn’t mean we stop wondering about what it is. There are a host of theories about how it comes to be.

Theories of Consciousness

The reductionist framework posits that consciousness arises out of, or emerges from, the behavior of the molecules or cells of the brain.  The most vociferous champions of this framework are Christof Koch and the late Francis Crick. Much of their discussion of consciousness focuses on the nature of wiring of neurons. Together they even went as far as to hypothesize the existence of a physical seat of consciousness, a super hub of information integration, suggesting  the claustrum as a likely candidate.  The late Gerald Edelman and Guilio Tononi have also been advocates of a different but nonetheless, biologically based hypothesis, that also calls upon the complex interaction of neurons, but differing mightily in the what and how of it.

A radically different approach suggests that the brain does not generate consciousness but is merely the substrate on which a larger global consciousness can play out.  One might think of this in terms of analogy to the color of an object.  Color depends fundamentally on the molecular structure and bonds within the object, but these molecules are not the generator of color itself.  Instead color is simply the consequence of the way light interacts with the bond structure.  However , it goes beyond this.  Advocates of a global consciousness such as philosopher Ervin Laszlo and physicist Amit Goswami call upon quantum physics and its astonishing revelation that the manifestation of a quantum probability requires an observer. Such a perspective inverts the paradigm from consciousness arising from matter to the suggestion that consciousness creates the material world.  Neurophilosopher Alva Noe suggests something slightly different that is perhaps somewhere in between – that consciousness is not a manifestation of brain alone but arises out a larger space of interaction between brain and the external world.

However, the point of this blog post is not to debate these various theories but rather point to what we do know and outline ways in which we can study it.

Manipulating Consciousness

Irrespective of theory, one thing is clear. Consciousness can be manipulated by a variety of mechanisms and this is interesting to study. Anesthetics make it disappear, psychedelic drugs such as LSD change its qualitative nature, and techniques such as meditation and hypnosis alter its state. And yes, EEG is a great tool to study this. What we can hope to understand with this approach is not the nature of consciousness itself, but the correlates of its subjective experience. And in doing so we might, perhaps, be able to better manipulate it to our advantage. This is not as odd as it sounds; our conscious experience encompasses our awareness, sensation, attention and moods and is much of what life comes to mean to us. And of course, for some experiences of life, it is just better that we have our consciousness knocked out of us.

Complexity in Consciousness

All the theories of consciousness might agree on one thing, that the complex interactions of the brain are somehow important. Indeed the complexity of brain activity plays center stage in what we know so far. The complexity or entropy of the EEG signal, irrespective of which way you compute it, tracks the level of anesthetic in your system to some degree. LSD creates a greater repertoire of patterns (see related article on Nootropics and Psychedelics). Does this mean that a certain degree of complexity is necessary for consciousness? Are there other correlates we have missed? Perhaps so, and it is worth probing more carefully. As our complexity shifts might we have different degrees of consciousness? Move through different phases of consciousness even over the day? Or is there a threshold at which consciousness appears? Surprisingly very little has been done to systematically study consciousness using anesthetics or psychotropic drugs.

Perceptual Rivalry

Another fascinating experimental paradigm for studying consciousness is the phenomenon of perceptual or binocular rivalry. Consciousness is a single integrated stream, or at least seems like it. When you show different images to each eye at the same time, it turns out, we can only see one or the other and the image we are conscious of switches back and forth every couple seconds or so. How we switch between which image we consciously perceive can potentially reveal important correlates of consciousness. That is not to say the brain doesn’t have signatures of the image that is not being consciously perceived. At least one paper has shown that it can still be detected in some manner using EEG.

A 2005 study by researchers Olivia Carter, Jack Pettigrew and others at the University of Queensland in Australia showed that Tibetan monks with long meditative practices could, to some degree, control how long they see one image versus another. This might bring us back to the ubiquitous alpha oscillation which monks can also control, leading us to an understanding of how attention and conscious perception are linked and how one can control conscious awareness.

Moving forward on consciousness

Moving forward in our understanding of consciousness requires an intersection of both theory and experiment. Consciousness has never been a serious consideration of neuroscientists but it shouldn’t be so. We may argue about ways to define it, get it wrong and update our view several times over, but that shouldn’t stop us from trying to unravel and manipulate it.

One thought on “Getting at Consciousness

  1. Dear Tara:

    Thank you for this article on a very important field of research!

    I would like to call your and the readers’ attention to a new synthesis that can be found in the papers posted in the following links:


    Alfredo Pereira Jr.
    São Paulo State University – Institute of Biosciences of Botucatu

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