McFadden’s EM Field Theory: Part II

This is the second part of two posts on a paper by Johnjoe McFadden Synchronous Firing and Its Influence on the Brain’s Electromagnetic Field Evidence for an Electromagnetic Field Theory of Consciousness.

The paper provides an overview of McFadden’s EM field theory of consciousness (cemi). In the first post, I focused mainly on eight predictions his theory makes. In this post, I want to focus on the parts of his argument about how EM field theory helps to answer some of the difficult problems in consciousness research.

McFadden begins with a discussion about various ways EM fields might be related to consciousness. McFadden takes what he calls a strong interpretation approach:

I propose here that our thoughts are similarly electromagnetic representations of neuronal information in the brain, and that information is in turn decoded by neurons to generate what we experience as purposeful actions or free will. This circular exchange of information between the neurons and the surrounding em field provides the ‘self-referring loop’ that many cognitive scientists have argued to be an essential feature of consciousness.

A strong interpretation can be contrasted with a weak interpretation that EM fields provide a sort of portal to view the brain’s internal operations or the epiphenomenal view that EM fields are present in the brain but are mostly side-effects of neurons firing that contribute little to consciousness.

McFadden also contrasts his approach also with Susan Pockett’s in his emphasis on informational aspects of EM waves and fields. In this regard he is careful to distinguish between synchrony of firing neurons that transmit information and excessive synchrony that transmits little information, such as the case of epileptic seizures.

Next he tackles five problems of consciousness research that he believes his theory helps to resolve. As before, the selected content below is quoted directly from paper. Highlights in bold are mine. I would especially like to call out his critique of the neural identity theory in the binding problem section.

1. The difference between conscious and unconscious information processing

In the cemi field theory, the neural circuits involved in conscious and unconscious actions are proposed to differ in their sensitivity to the brain’s em field. During unconscious driving, the sensory and motor activity responsible for the driving the car would have been performed by neurons with membrane potentials far from the critical threshold for firing (either positively or negatively) and thereby insensitive to the brain’s em field. When new or unusual stimuli reach the brain (presence of child on road) the consequent synchronous firing of neurons involved in processing that new information would transmit the information to the brain’s em field, allowing it to reach our conscious awareness. This additional sensory input may shift the membrane potential of some of the neurons involved to near the firing threshold and thereby make the whole neuronal pathway sensitive to augmentation by the brain’s em field. Our conscious mind — the cemi field — does indeed take over.

The cemi field theory also provides a natural explanation for how, in the words of Bernard J. Baars (1993), ‘a serial, integrated and very limited stream of consciousness emerge from a nervous system that is mostly unconscious, distributed, parallel and of enormous capacity’.

2. The role of consciousness in memory

If the target neurons for em augmentation are connected by Hebbian synapses then the influence of the brain’s em field will tend to become hard-wired into either increased (long-term potentiation, LTP) or decreased (long-term depression, LTD) neural connectivity. After repeated augmentation by the brain’s em field, conscious motor actions will become increasingly independent of em field influences.

Similarly, in the absence of any motor output, the cemi field may be involved in strengthening synapses to ‘hard-wire’ neurons and thereby lay down long-term memories.

3. The nature of free will

Therefore, whereas in agreement with most modern cognitive theory, the cemi theory views conscious will as a deterministic influence on our actions, in contrast to most cognitive theories it does at least provide a physically active role for ‘will’ in driving our conscious actions. In the cemi field theory, we are not simply automatons that happen to be aware of our actions. Our awareness (the global cemi field) plays a causal role in determining our conscious actions.

4. The nature of qualia

However, awareness per se, without any causal influence on the world, cannot have any scientific meaning since it cannot be the cause of any observable effects. In the cemi field theory, consciousness — the cemi field — is distinct from mere awareness in having a causal influence on the world by virtue of its ability to ‘download’ its informational content into motor neurons. It therefore corresponds quite closely to what Ned Block terms (Block, 1995) ‘access consciousness’. How far animals or inanimate informational systems are conscious will depend on whether they possess complex information fields that are capable of having a causal influence on the world. This may well be amenable to experimental testing.

Since, in the cemi field theory, a conscious being is aware of the information contained within the cemi field, qualia — the subjective feel of particular mind states — must correspond to particular configurations of the cemi field. The qualia for the color red will thereby correspond to the em field perturbations that are generated whenever our neurons are responding to red light in our visual field. However, since at the level of the brain’s em field, sensory information may be combined with neuronal information acquired through learning, the ensuing field modulations would be expected to correlate not with the sensory stimuli alone, but with the meaning of particular stimuli. This was indeed what Freeman discovered in his classic experiments on rabbit olfaction (Freeman, 1991).

5. The binding problem

To illustrate the problem, consider two entirely independent neural networks (either biological or artificial): the first is able to recognize green objects, and the second is able to identify round objects. If an apple is presented to both networks then, in a neural identity theory of consciousness, each network would (if sufficiently complex) experience their own particular qualia for roundness or greenness. But now we add a wire (or neuron) that connects the two networks so that the combined assembly is able to recognize objects that are both round and green. A neural identity theory would then predict that the enlarged network should experience qualia in which roundness and greenness are somehow bound together in a way analogous to our own conscious perception of an apple. Yet the only additional input that either network would have received is a single binary digit travelling down the connecting wire from the adjacent network. Neither ‘roundness’ nor ‘greenness’ could be fully described by a single binary digit. To account for the existence of unified qualia that includes the information coming from both networks, the neural identity theory must propose some overarching reality that connects and unifies the two networks. But no such overarching reality exists — at least at the level of matter

But in the human brain, there is an overarching reality that connects neural networks: the brain’s electromagnetic field. At the field level, and in contrast to the neuronal level, all aspects of the information representing the apple (colour, shape, texture etc.) are physically linked to generate a single physically unified and coherent modulation of cemi field that represents conscious perception.

The cemi field theory is compatible with many contemporary theories of consciousness. The cemi field can be considered to be a global workspace (Baars, 1988) that distributes information to the huge number of parallel unconscious neural processors that form the rest of the brain. Similarly, the brain’s em field may be considered to be the substrate for Dennett’s multiple drafts model (Dennett, 1991) since its informational content will be continually updated by neuronal input until a field configuration is reached that is capable of generating ‘output’ that is downloaded as motor actions or the laying down of memories. The theory also has much in common with quantum models of consciousness (Penrose, 1995) since both propose a field-level description of consciousness. However in contrast to quantum consciousness models that must propose a physically unrealistic level of quantum coherence between neurons or microtubules within neurons, the cemi field theory has no such requirement.


Posted in Consciousness, Waves | 16 Comments

McFadden’s EM Field Theory: Part I

During the course of responding to my previous post, I came upon a paper by Johnjoe McFadden Synchronous Firing and Its Influence on the Brain’s Electromagnetic Field Evidence for an Electromagnetic Field Theory of Consciousness.

This is a remarkable paper written in 2002 that outlines his theory (cemi) and makes some of the strongest arguments for EM field theories of consciousness I’ve seen. I don’t know how much has changed since it was written. There is an enormous amount of detail in it. So caution is called for. Some of the studies he cites may have been invalidated and others may exist that support or disapprove some of his arguments. I am breaking this post into two parts as I absorb the paper. This one is focuses on eight specific testable predictions he makes for his theory:

(1) Stimuli that reach conscious awareness will be associated with em field
modulations that are strong enough to directly influence the firing of motor
(2) Stimuli that do not reach conscious awareness will not be associated with em field modulations that affect motor neuron firing.
(3) The cemi field theory claims that consciousness represents a stream of information passing through the brain’s em field. Increased complexity of conscious thinking should therefore correlate with increased complexity of the brain’s em field.
(4) Agents that disrupt the interaction between the brain’s em field and neurons will induce unconsciousness.
(5) Arousal and alertness will correlate with conditions in which em field fluctuations are most likely to influence neuron firing; conversely, low arousal and unconsciousness will correlate with conditions when em fields are least likely to influence neuron firing.
(6) The brain’s em field should be relatively insulated to perturbation from exogenous em fields encountered in normal environments.
(7) The evolution of consciousness in animals should correlate with an increasing level of electrical coupling between the brain’s endogenous em field and (receiver) neuron firing.
(8) Consciousness should demonstrate field-level dynamics.

McFadden goes on to discuss the existing evidence for each prediction. Various selected content from the ones that caught my attention follows. His discussion of number 8 is the most interesting even though there is less experimental evidence for it at the time of the paper. All content below is quoted directly from paper. Highlights in bold are mine.

Prediction 1

Sensory or motor information that is transmitted just by neuron firing will tend to scale arithmetically: the greater the stimulus or response, the more neurons are likely to be involved. However, because the em field is a wave-mechanical phenomenon the magnitude of its modulations will be proportional only to the number of those neurons that fire synchronously. The cemi field theory therefore predicts that conscious awareness will not correlate with neuron firing per se but with the synchrony of neuron firing. As outlined in the Introduction, numerous studies have indeed indicated that whereas neuron-firing patterns alone do not correlate with awareness, their level of synchrony does.

Prediction 2

There is abundant evidence that the loss of awareness of repeated stimuli during habituation is associated with a reduction in amplitude of either EEG or MEG evoked potential signals (Coull, 1998; Hirano et al., 1996) and thereby the synchronous neuron firing patterns that generate those signals. Loss of awareness therefore correlates with reduced disturbance to the brain’s em field (Anninos et al., 1987; Hulstijn, 1978; Leaton and Jordan, 1978; Rockstroh et al., 1987).

Prediction 4

Examining the third prediction, there is evidence that anaesthetics that decrease awareness of stimuli disrupt synchronous firing (Southan and Wann, 1989; Whittington et al., 1998) and thereby reduce the influence of the em field on neuron firing. The onset of unconsciousness due to a variety of agents e.g. asphyxia or anesthesia is associated with a reduction of amplitude of EEG signals (McPherson, 1998), indicating that loss of consciousness is associated with disruption to neuronal synchronization (Speckmann and Elger, 1998) and consequent weak endogenous em fields. As mentioned above, disruption of synchronous firing in insects by treatment with picrotoxin reduces their ability to discriminate between scents.

Prediction 5

The cemi field theory predicts that the increased levels of arousal (increasing conscious control of actions) should be associated with strong coupling between the brain’s em field and neuron . Increased amplitude of visually evoked potentials is also associated with short reactions times in monkeys (Chalupa et al., 1976; De Giorgio et al., 1993). The level of spatial coherence of EEG patterns — which is a reflection of the coherence of the underlying endogenous em fields — is also found to correlate with attention and awareness. For instance, in a recent study, the level of EEG spatial coherence was found to be related to the level of creativity needed to solve a problem (Jausovec and Jausovec, 2000). Spatial coherence was also found to increase during transcendental meditation (Travis and Wallace, 1999). Conversely, loss of EEG spatial coherence was found to correlate with increasing cognitive impairment in HIV patients (Fletcher et al., 1997).

Prediction 6

The high conductivity of the cerebral fluid and fluid within the brain ventricles creates an effective ‘Faraday cage’ that insulates the brain from most natural exogenous electric fields. A constant external electric field will thereby induce almost no field at all in the brain (Adair, 1991). Alternating currents from technological devices (power lines, mobile phones, etc.) will generate an alternating induced field, but its magnitude will be very weak. For example, a 60 Hz electrical field of 1000 V/m (typical of a powerline) will generate a tissue field of only 40 µV/m inside the head (Adair, 1991), clearly much weaker than either the endogenous em field or the field caused by thermal noise in cell membranes. Magnetic fields do penetrate tissue much more readily than electric fields but most naturally encountered magnetic fields, and also those experienced during nuclear magnetic resonance (NMR) scanning, are static (changing only the direction of moving charges) and are thereby unlikely to have physiological effects. Changing magnetic fields will penetrate the skull and induce electric currents in the brain. However, there is abundant evidence (from, e.g., TMS studies as outlined above) that these do modify brain activity. Indeed, repetitive TMS is subject to strict safety guidelines to prevent inducing seizures in normal subjects (Hallett, 2000) through field effects.

Prediction 8

The last prediction of the cemi theory — that consciousness should demonstrate field-level dynamics — is perhaps the most interesting, but also the most difficult to approach experimentally. In principle it should be possible to distinguish a wave-mechanical (em field) model of consciousness from a digital (neuronal) model. Although neurons and the fields generated by neurons hold the same information, the form of that information is not equivalent. For instance, although a complete description of neuron firing patterns would completely specify the associated field, the reverse is not true: a particular configuration of the brain’s em field could not be used to ‘reverse engineer’ the neuron firing patterns that generated that field. This is because any complex wave may be ‘decomposed’ into a superposition of many different component waves: a particular field configuration (state of consciousness) may be the product of many distinct neuron-firing patterns. The cemi field theory thereby predicts that if distinct neuron firing patterns generate the same net field then, at the level of conscious experience, those firing patterns should be indistinguishable. In principle at least, this issue could be resolved experimentally.

Experiments could be designed to investigate whether wave-mechanical interference is a factor in conscious awareness. Field level informational processing may also endow consciousness with properties that are absent, or more complicated to emulate, in a digital system. For instance, wave-mechanical dynamics may allow Fourier-type (harmonic analysis) of information held in the conscious field, providing a possible mechanism for the ability of some individuals to hear pure tones in complex sound waves. MacLennan (1999) has recently argued that many mind processes may usefully be described as field-level computations.


Click to access MCFSFA.pdf

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Decisions, Decisions

A new paper in Cell measures theta waves in the hippocampus of rats navigating a maze with multiple spatial paths. They found a decision-making process seemed to be involved consistently with theta wave patterns. The paper itself requires a subscription or purchase but there is a good article on it in Quanta Magazine.

The hippocampus generated a representation of the left-turning choice during one cycle, then switched to the right-turning choice for the next one. The scenarios didn’t always alternate perfectly throughout the experiment — occasionally the same one would persist for a few cycles — but the structure in the signals was undeniable. The 125-millisecond sequences seemed to segregate the brain’s different hypotheses about the future into a continuous and consistent overall framework.

One could regard the brain waves themselves as incidental to the decision-making that is really being done by the brain circuits, but this association of brain waves with cognitive processes is what would be expected by EM field theories.

Posted in Consciousness, Electromagnetism, Waves | 17 Comments