If consciousness is in some way physical, what exactly composes it?
The widely discussed theories today seem to fall into one of two categories:
- Consciousness is information processing in one form or another. (CIP)
- Consciousness is composed of or created by something exotic like some consciousness attribute attached to all matter or quantum computing. (CEX)
CIP theories are alluring because it certainly looks like brains process information. Sense information goes in. Processing happens. Neurons fire. We apparently see, hear, or sense something. Maybe we take an action. Maybe we ponder. The more neurons fire, the bigger the brain, the more conscious the creature appears to be be. Don’t forget that neurons look and act a little like switches that go on and off and there are a bunch of them connected in the brain. That seems like a computer. Hence, CIP.
CEX theories appeal to a gut feeling that there is something really special or different about consciousness. Consciousness doesn’t seem material. How does it come from matter? It seems somewhat mysterious. We must find something that is a little more than plain matter as we know it to explain it. Hence, CEX.
CIP has never been persuasive to me. I don’t doubt information processing is happening in the brain but I’ve never quite grasped how the leap from it to consciousness could occur. I’ve been intrigued with CEX, especially the quantum computing theories of Hameroff and Penrose, but ultimately there is still seems to be a gap. Even if quantum processes are occurring in the brain, how would they assemble into a coherent consciousness? The same question could asked about some panpsychic material attribute (for which, by the way, we have no evidence).
Is the solution to explaining this much simpler? Maybe something that we have known about for years?
3. Consciousness arises from spatiotemporal, electromagnetic wave forms that result from neurons firing. (CEM)
The evidence for electrical activity and electromagnetic activity in the brain is overwhelming. Electroencephalography dates from the nineteenth century. EEGs are routinely used in medical to diagnose neurological disease and brain damage. States of consciousness – wakefulness, deep sleep, dreaming sleep, anesthetic induced unconscious – all have distinctive electrical brain wave patterns. This is all occurring at a global, whole brain level. At the local neuron level, each firing of a neuron results in a movement of ions and creates a weak electromagnetic field. Neurons firing in sync create a larger electromagnetic field. Neurons firing in sync are correlated with consciousness.
CEM in its own way has the exotic qualities of CEX. Electromagnetism is physical and measurable but not solid and material like atoms and molecules. In contrast to debatable theories about quantum processing in the brain or unknown mental attributes to particles, it is well known and understood scientifically. It is pervasive in the living brain which is where we think consciousness resides and which is the only place in the body that has complex and constant electromagnetic activity. CEM also meshes well with CIP. If neurons firing is information flow, it also happens to be what produces electromagnetic fields in the brain.
Those arguments by themselves may not make a strong case for CEM but I would at least think it would put it in the discussion for possible explanations of consciousness. CEM receives little or no attention in the journals. Few researchers seem to be working in the area. CEM seems to reside in the province of lunatics and cranks. On the talk page of Wikipedia for Electromagnetic theories of consciousness (not a bad high level overview by the way), the first comment is:
Everything about the article smells of yet another crank theory invented by some “philosopher” who happens to dabble in physics. Short of nominating it for deletion, would someone care to rewrite the article, and condense it to one or two paragraphs? That’s way more than it deserves.
My own attitude initially toward it was similar although not quite so derisive. For one thing, the idea seems a little nineteenth or early twentieth century from around the time of the discovery of radio waves. It seems to align with the idea of the brain/mind as a transmitter and/or receiver. It also reminds of people receiving messages or hearing voices in their head. In more recent times it makes one think of electromagnetic hypersensitivity and controversies about brain damage caused by cell phones.
Since I began to look at a comprehensive theory, however, my attitude about it has changed. The theory I have focused most on is by Susan Pockett. I’ll get to why I have been drawn to her in a moment. There are a few other researchers in this area and some on the fringe of it. I also have a learning curve with some of the science – not only the electrochemistry of neurons but some of the basics of electromagnetism (with a lot I never knew and a lot of what I once knew forgotten). So my learning process on this is just beginning and my views could change. At this point, I think CEM may be the best approach to understanding how consciousness works.
Let me provide a brief account of how I got to this point. My last two posts have related to the paper Coupling the State and Contents of Consciousness. The core argument in that paper is that consciousness depends critically on activity in the layer 5 pyramidal neurons. If the argument for L5 pyramidal neurons is even partially correct, there must be something in the architecture of these neurons that enable consciousness. I wandered into Susan Pockett’s work looking around for something special that might be tied to the L5 pyramidal neurons.
Neurons are defined as electrically excitable cells and usually consist of a cell body and two types of slender extensions: dendrites which usually receive input and an axon that usually transmits information away from the body. Pyramidal neurons, in addition to having a pyramid-like main cell body, have a apical dendrite that extends from the apex (hence “apical”) of the body. They are found in the cortex, the amygdala, and the hippocampus. There are billions of pyramidal neurons in the brain and, in the cortex, they line up roughly in parallel. The body of the L5 pyramidal neurons sits in layer 5 of the cortex but the extensions extend from the bottom of the cortex to the top of the cortex. The apical dendrite, in particular, runs from the neuron body in layer 5 through the entire cortex to the top.
The function of the apical dendrite isn’t well understood. From the neuron base it extends to what is called an apical tuft at the top of the cortex. This allows connections to the apical terminations of other neurons on the surface of the cortex. While dendrites in general receive input, there is evidence of bidirectional flow in the apical dendrite. One theory, developed by LaBerge and Kasevich, sees a major role for the apical dendrite in synchronizing the firings of groups of neurons. In their The apical dendrite theory of consciousness paper, they write (parts in bold are by me) :
The neural basis of consciousness is theorized here to be the elevated activity of the apical dendrite within a thalamocortical circuit. Both the anatomical and functional properties of these two brain structures are examined within the general context of the cortical minicolumn, which is regarded as the functional unit of the cerebral cortex. Two main circuits of the minicolumn are described: the axis circuit, which sustains activity for extended durations and produces our sensory impressions, and the shell circuit, which performs input-output processing and produces identifications, categorizations, and ideas. The apical dendrite operates within the axis circuit to stabilize neural activity, which enables conscious impressions to be steady and to be sustained over long periods of time. In an attempt to understand how the conscious aspect of subjective impressions may be related to apical dendrite activity, we examine the characteristics of the electric and magnetic fields during the movement of charges along the apical dendrite. The physical correlate of consciousness is regarded here as the relatively intense electromagnetic field that is located along the inside and the outside close to the surface of the active apical dendrite.
With this as background, I wandered into The Electromagnetic Field Theory of Consciousness A Testable Hypothesis about the Characteristics of Conscious as Opposed to Non-conscious Fields by Susan Pockett. Once again the pyramidal neurons put in an appearance with a specific proposal about why these neurons would be associated with consciousness. There was the below diagram with this explanation: “The hypothesis proposed here is that one necessary (albeit clearly not sufficient) characteristic of conscious as opposed to non-conscious EM fields or patterns of charge is a spatial structure something like that shown in Figure 3 [below]. The essence of the proposal is that in the radial direction (perpendicular to the surface of the cortex) conscious fields will have a surface layer of negative charge above two deeper layers of positive charge, separated by a distinct neutral layer.”
I don’t know if her specific proposal is correct, but I had to be intrigued by the correspondence between it and the LaBerge-Kasevich theory as well as the coupling state and content paper I’ve been following.
Pockett’s hypothesis, in more general terms, is : “The electromagnetic field theory of consciousness proposes that conscious experiences are identical with certain electromagnetic patterns generated by the brain.” In her theory consciousness would be possible outside of wet brains. Any material which could create the correct spatiotemporal EM wave forms would have consciousness. What’s more, consciousness might not be limited in biological organisms to organisms with structures exactly like those in the diagram found in the mammalian brain. In her book The Nature of Consciousness: A Hypothesis she discusses evidence of EM waves associated with insect olfaction and speculates that even insect could possess a rudimentary consciousness.
Pockett’s version of the hypothesis is that consciousness is identical with certain EM wave forms. Not all wave forms will be conscious. She admits we don’t know the exact characteristics of the wave forms which are conscious but has ideas for researching the problem.
A weaker version of the CEM would be that consciousness is not identical with certain EM wave forms but that consciousness is a sort of internal sensing of EM wave forms. Since we do not have anything resembling receptors in the brain itself, this seemingly would require that the neurons, probably the same ones involved in producing the EM waves, act as both generators and receptors of EM waves. I don’t know if this is possible so I provide the idea only as additional speculation. If this speculation is true, the feels like to be something in Nagel’s definition of consciousness would be the experience of EM fields.
Let me spend some time reviewing some of the arguments in favor of CEM as well as some major objections.
First, let me review a few items. We’ve known since Faraday that electricity and magnetism are somewhat interchangeable. A current travelling in an electric wire produces a magnetic field around it and rotating a wire in a magnetic field will create a current in the wire. Neurons generate electrical signals as ions flow through permeable membranes so these flows, just like current in a wire, produce electromagnetic fields around them. These fields are extremely weak and low frequency, in the range of 0-100 hertz range.
CEM doesn’t require new forces, exotic quantum effects, or a miraculous emergence of consciousness from information processing. It hypothesizes consciousness arises from a well-known physical force. As previously mentioned, evidence of electrical and electromagnetic activity in the brain has been known since the invention of electroencephalography in the late nineteenth century. EEGs are routinely used in many neuroscience experiments, for detection of disease and abnormalities, and for determination of comatose conditions. They can reliably detect overall brain state. Since the days of Wilder Penfield it has been known that direct electrical stimulation of the brain can create experiences. This includes memories and hallucinations. Transcranial magnetic stimulation (TMS) has been shown to generate a range of cognitive disturbances in subjects including: modification of reaction time, induction of phosphenes, suppression of visual perception, speech arrest, disturbances of eye movements and mood changes. TMS has been used to restore some experience of color where before there was no visual awareness whatsoever. So clearly there is electromagnetic activity in the brain and electromagnetic activity has an effect on consciousness.
A common objection to CEM is that, if consciousness is generated by electromagnetic fields, we would expect interference from the wide variety of electromagnetic radiation we are exposed to daily. The EM waves in the brain are weak and low frequency. The fields generated by neurons can affect other neurons because they are in extremely close proximity and in the right frequency range. The amount of radiation from other external sources is minuscule in the frequency ranges of brain waves. Strong stimulation, as with TMS as discussed above, actually does have effects on consciousness.
CEM addresses what is one of the most perplexing problem in neuroscience: how does the brain synchronize brain activity to create a unitary experience. This is what is known as the binding problem. To quote from the McGill brain site:
So if there is no single place where all of the information about an object converges to become conscious, is there perhaps a single time when it does? That is the other major approach to solving the binding problem, and it seems the more promising. In this approach, broadly speaking, neurons that are active at the same time are believed to be “perceiving the same thing”. In technical terms, this approach is based on the temporal synchronization of neuronal activity.
Christof von der Malsburg was one of the pioneers of this approach. In the early 1980s, he began to explore the hypothesis that the key to the binding problem might lie in the synchronized activity of the neurons that process the various properties of an object.
Andreas Engel and Wolf Singer subsequently confirmed that this hypothesis was well founded. Several of their experiments seemed to indicate that the objects represented in the visual cortex are in fact represented by assemblies of neurons that are firing simultaneously.
CEM can explain the binding problem by propagation of modulations of EM waves across the brain. Like a tuning fork, sharing the same natural frequency with another vibrating tuning fork that is placed nearby, will begin to resonate with the vibrating tuning fork, groups of neurons will begin resonate together by firing in sync. With small groups start to fire in sync, the EM signal is boosted which can then trigger groups at larger distances to resonate in sync.
Consciousness in this theory seems more like a elaborate symphony with complex harmonics and counterpoints than the clicking and clacking of an adding machine.
CEM doesn’t need to explain all neural activity or information flow in the brain as produced by EM waves. Undoubtedly a lot of what goes on the brain is neurons firing other neurons. Certainly once a decision is made to wiggle your foot, undoubtedly the neural signal follows familiar electro-chemical pathways from the brain to the muscles of the foot and leg.
It is possible that simple brains and nervous systems do not make use of EM fields. EM fields may simply be side-effects of electro-chemical transmissions in such systems with no effect on capability. As brain got larger, evolution was faced with the problem of how to synchronize activity in real time across much larger distance. The already existent EM fields may have been recruited for this purpose and created an alternate information flow path. Consciousness might have been an inadvertent result.
I don’t know whether CEM will ultimately work out, but personally I am finding CIP and CEX to be dead ends. At any rate, I would be surprised if EM waves are completely inconsequential in the brain even if they do not provide a complete explanation for consciousness.