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The Electromagnetic Field Theory of Consciousness A Testable Hypothesis about the Characteristics of Conscious as Opposed to Non-conscious Fields

November 2012
Journal of Consciousness Studies 19(11)

Authors:

University of Auckland

The electromagnetic field theory of consciousness proposes that conscious experiences are identical with certain electromagnetic patterns generated by the brain. While the theory has always acknowledged that not all of the electromagnetic patterns generated by brain activity are conscious, until now it has not been able to specify what might distinguish conscious patterns from non-conscious patterns. Here a hypothesis is proposed about the 3D shape of electromagnetic fields that are conscious, as opposed to those that are not conscious. Seven predictions arising from this hypothesis are described. Existing empirical evidence shows that four of these predictions have already been successfully tested. Requirements for experimental testing of the other three are discussed.

Diagrammatic representation of the generation of LFPs (local field potentials).

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LFPs in neocortex.

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Sensory input to layer 4 does not generate measurable LFPs.

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3D model of conscious field. Grey layer in middle of column 1 is neutral.

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Hypothesized distribution of electric charge in brain-generated fields that are (A) conscious and (B) non-conscious (one example from many possibilities). Roman numerals to left indicate cortical layers.

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Content uploaded by Susan Pockett

Content may be subject to copyright.

Susan Pockett

The Electromagnetic Field

Theory of Consciousness

A Testable Hypothesis about

the Characteristics of Conscious

as Opposed to Non-conscious Fields

Abstract: The electromagnetic field theory of consciousness proposes

that conscious experiences are identical with certain electromagnetic

patterns generated by the brain. While the theory has always acknow-

ledged that not all of the electromagnetic patterns generated by brain

activity are conscious, until now it has not been able to specify what

might distinguish conscious patterns from non-conscious patterns.

Here a hypothesis is proposed about the 3D shape of electromagnetic

fields that are conscious, as opposed to those that are not conscious.

Seven predictions arising from this hypothesis are described. Existing

empirical evidence shows that four of these predictions have already

been successfully tested. Requirements for experimental testing of the

other three are discussed.

1. Introduction

The definition of consciousness is famously difficult. Not only is it

true that, as Searle (1993) says, ‘Like most words, “consciousness”

does not admit of a definition in terms of genus and differentia or nec-

essary and sufficient conditions’, but also ‘consciousness’ is even

worse than most words in that the phenomenon it describes is so

Journal of Consciousness Studies,19, No. 11–12, 2012, pp. 191–223

Correspondence:

Susan Pockett, Department of Psychology, University of Auckland, Private Bag

92019, Auckland, New Zealand. Email: s.pockett@gmail.com

For personal use only -- not for reproduction

private that it is impossible to know for sure whether it even exists in

any entity other than oneself. Nonetheless, as Searle goes on:

It is important to say exactly what we are talking about, because the phe-

nomenon of consciousness that we are interested in needs to be distin-

guished from certain other phenomena such as attention, knowledge

and self-consciousness. By ‘consciousness’, I simply mean those sub-

jective states of sentience or awareness that begin when one wakes up in

the morning from a dreamless sleep and continue throughout the day

until one goes to sleep at night or falls into a coma, or dies, or otherwise

becomes, as one would say, ‘unconscious’. (Ibid.)

I will take this as a working definition for the purposes of this essay, in

hopes that a better definition may eventually be possible as a result of

the experiments proposed here.

The problem about developing a better definition of consciousness

is that in order to define something, you have to know what it is. While

we can each experience from moment to moment the contents of our

own consciousness, we do not yet know what consciousness in gen-

eral — as opposed, for example, to matter in general — is. There are

presently a large number of theories about what consciousness is.

There are dualist or semi-dualist theories, which say that at least some

aspect of consciousness is not physical. There are quantum mechani-

cal theories, which say that consciousness is physical, but just as onto-

logically mysterious or hard to understand in everyday terms as

everything else about quantum mechanics. Finally, there are at the

moment three main non-quantum theories which are distinctive

enough to drive a particular experimental programme.

(1) The psychoneural identity theory was originally proposed by the

philosophers Place (1956), Feigel (1958), and Smart (1959), and

rebranded some decades later as ‘the astonishing hypothesis’

(Crick, 1994). This idea is summarized as follows: ‘The Aston-

ishing Hypothesis is that “You”, your joys and your sorrows,

your memories and your ambitions, your sense of personal iden-

tity and free will, are in fact no more than the behavior of a vast

assembly of nerve cells and their associated molecules. As Lewis

Carroll’s Alice might have phrased it: “You’re nothing but a pack

of neurons”’ (Crick, 1994, p. 3). It isnever specified by thishypo-

thesis exactly what makes the behaviour of some neurons conscious

and others not, but the unspoken consensus at present seems to be

that particular patterns of action potential firing may be the key.

Thus the experimental paradigm dictated by this theory tends to

involve the recording of single units, which are an extracellular

192 S. POCKETT

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measure of the firing of individual neurons. While neurophysio-

logists as a group usually prefer not to think about consciousness at

all, the scientific tribe who are most comfortable with the psycho-

neural identity theory do tend to be neurophysiologists.

(2) The second major idea about the nature of consciousness that

presently drives a particular experimental approach is function-

alism. Both the provenance and the defining assertion of func-

tionalism are succinctly expressed by Tononi and Edelman

(1998): ‘Consciousness, as William James pointed out, is not a

thing, but a process or stream that is changing on a time scale of

fractions of seconds (James 1890).’Since the mantra of function-

alists is ‘consciousness is a process, not a thing’, this group of

workers are not very interested in the specific neural correlates of

consciousness, preferring to study the abstract processes that

underpin mental functions. Generalization is always dangerous,

but the main scientific group who take this approach tend to be

psychologists. Artificial intelligence (AI) aficionados and to a

certain extent connectionists also appreciate the possibility

promised by functionalism of producing consciousness by repli-

cating functions using hardware instead of wetware.

(3) The third major idea about the nature of consciousness that has

the potential to drive a distinct experimental paradigm is the elec-

tromagnetic (EM) field theory of consciousness (Pockett, 1999;

2000; 2002; 2007; 2011). This theory proposes that conscious

experiences are identical with certain spatial EM patterns gener-

ated by neural activity in the brains of conscious subjects. While

the EM field theory is an identity theory, it differs radically from

the psychoneural identity theory in that (like functionalism) it

predicts the possibility of producing consciousness without neu-

rons. According to the EM field theory, putatively conscious EM

fields could in principle be generated using hardware instead of

wetware. There are major differences between the EM field the-

ory and either functionalism or connectionism with regard to the

methodology for generating such non-biological consciousness:

while the approach of the EM field theorist would be to measure

the 3D shape of the putatively conscious fields produced by the

brain and reproduce these fields artificially, the approach of

connectionists and present-day AI workers would be to model

the functions performed by the brain and hope that any model or

instantiation which reproduces the function will reproduce what-

ever conscious experience goes with the function. However,

there is no intrinsic incompatibility or argument between EM

THE ELECTROMAGNETIC FIELD THEORY 193

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field theorists and functionalists. The EM field theory essentially

provides a means of reifying functionalism, by removing the rea-

son for the latter’s prohibition of ‘things’ as the basis of con-

scious experiences. Electromagnetic fields are like things, but

unlike material things they can and do change on a time scale of

fractions of seconds. The current experimental programme that

best fits the EM field theory of consciousness involves recording

scalp or intracranial EEG (although most scientists who use

those techniques at present either don’t know about the EM field

theory of consciousness or actively repudiate it). The hypothesis

put forward in the main body of this paper points the way to a dis-

tinctly new experimental paradigm, which promises to reveal the

3D shape of conscious EM fields.

Three useful objections to the EM field theory of consciousness

As with any novel theory, a number of objections to the EM field the-

ory of consciousness have been raised. Six of the most common ones

were answered in the original statement of the theory (Pockett, 2000).

However, over the last eleven years three more objections have arisen

which are not answered by Pockett (2000). There is no doubt that

objections to a theory can be extremely useful: the answer to the sec-

ond of these objections has recently allowed an answer to the third,

and the answer to the third is here expanded into the hypothesis out-

lined in the present paper. To take them one by one, the three objec-

tions and their answers are as follows.

Objection 1

The first objection is that it is not intuitively obvious why — or in

more extreme versions of the objection ‘remotely plausible’ that —

any particular spatial electromagnetic pattern should be identical with

a particular conscious experience. What can it be, the objector asks,

about possessing this specific spatial pattern that gives an EMfield the

characteristic features of conscious experiences: qualia, subjectivity,

privileged access, whatever?

Answer to Objection 1

Aside from the privileged access part, which is easy (see Objection 2),

this question is exactly analogous to asking a physicist to explain what

it is about the arrangement of mass/energy into a particular spatial pat-

tern of atoms and molecules that gives it the characteristic features of

matter. This is a question that is unlikely to be asked. If it were, the

physicist’s response would probably be bemused incomprehension.

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The issue here is that to those of us who were educated in the ‘de-

veloped’ world in the latter half of the twentieth century, it seems com-

pletely unremarkable that matter should be composed of molecules,

atoms, electrons, protons, and an ever-expanding zoo of smaller parti-

cles, and that different forms of matter should exist as a result of dif-

ferent arrangements of these entities. It does not seem necessary to ask

why this should be so — we simply accept that this is the way matter

is. But if these ideas seem in any way inherently or intuitively plausi-

ble to us (as opposed to plausible because they have been experimen-

tally proven over the course of several centuries) it is only because we

are so familiar with them. Were we living in, say, China during the

fourteenth century, we would almost certainly greet the same ideas

with undisguised scepticism and a polite request that it should be

explained to us why any sane person should even entertain the thought

that an obviously solid rock is actually composed of tiny, invisible bits

of buzzing energy. (Where on earth does THAT idea come from? we

might have asked — to which our fourteenth century atomist might

have responded with a long peroration about the philosophical origins

of atomist ideas in both ancient Greece and ancient India1— but that’s

beside the point.)

The point is that intuition can be trained. When it comes to mind,

which has traditionally been set in opposition to matter, most of us are

not — yet, perhaps — used to the idea that consciousness is composed

of spatial electromagnetic patterns. So that idea does not — yet, per-

haps — seem ‘remotely plausible’. But should that idea eventually be

shown to withstand experimental scrutiny as robustly as the idea of

atoms did, we will no doubt again stop asking why things should be so

and accept that this is just the way consciousness is. That time may yet

be some way off: my estimate is that we are presently at about the

same stage with regard to proving the existence of conscious EM

fields as Newton, Boyle, Huygens, Leeuwenhoek, and Halley were

with regard to proving the existence of material atoms in the latter half

of the seventeenth century. (But on the question of where this not-

yet-intuitive idea about consciousness came from, yes, what could be

seen as a field theory of consciousness was also put forward in both

ancient India and ancient Greece — Pockett, 2000.)

Objection 2

The second major objection to the EM field theory of consciousness

that was not answered by Pockett (2000) pertains to one of the

THE ELECTROMAGNETIC FIELD THEORY 195

[1] Leucippus and Democritis taught atomism in Greece around 450 BC. Kanada wrote the

explicitly atomistic Vaisesika Sutras in India around 200 BC. See Pockett (2000).

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features of the idea that was originally touted as a major point in its

favour. Electromagnetic fields are well documented to be capable of

causing neurons to fire. This, it was suggested at some length in Chap-

ter 7 of Pockett (2000), provided a potential physical mechanism by

which consciousness could cause behaviour. But the objection to that

idea was not long in coming — and this time the objector was the

author of the original theory herself (Pockett, 2002).

The objection hinges on the fact that the sorts of EM patterns pro-

posed by the theory as being conscious are extremely local. They fall

off with distance according to not merely an inverse square law, but an

inverse cube law (Pockett, 2011). This means that they exist at all only

within a few millimetres of the neurons that generate them. Such

extreme ‘localizedness’ is reflected in the name of the individual EM

waveforms that make up each putatively conscious pattern — local

field potentials, aka LFPs. It means that these patterns (i) cannot be

shared with other conscious entities (which explains the privileged

access part of Objection 1); and more importantly (ii) are not even

accessible to the neurons within the same nervous system that directly

cause behaviour. The neurons that most directly cause behaviour are

motor neurons in the spinal cord. These are largely driven by neurons

in the primary motor cortex, which in turn are driven by neurons in the

premotor and supplementary motor areas of the cortex, with a good

deal of interplay from subcortical structures. Simple physics dictates

that the putatively conscious EM patterns generated by most other

areas of brain (with the possible exception of primary somatosensory

cortex, although there the orientation of the pattern poses a problem)

are too far away to be accessible to any of these neurons. So Objection

2 is that putatively conscious EM field patterns cannot directly cause

the firing of motor neurons. They cannot be the direct cause of

behaviour.

For a while, this objection seemed fatal to the theory. If, as we all

intuitively believe, voluntary behaviour is directly caused by con-

sciousness; and if behaviour cannot be directly caused by the EM pat-

terns this theory talks about; then consciousness cannot be the EM

patterns this theory talks about.

Answer to Objection 2

The answer to this objection lies in the assumption that voluntary

behaviour is directly caused by consciousness. It seems that in this

respect intuition has let us down again. Consciousness does not

directly cause voluntary behaviour (Pockett, 2004; 2011; Pockett et

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al., 2006; 2009). Observations leading to this conclusion include the

following:

(1) The conscious experience of willing or causing a movement is

neither necessary nor sufficient for the performance of voluntary

actions. Wegner (2002) discusses a wide variety of circum-

stances in which subjects either perform apparently volitional

actions without consciously willing them (conscious will is not

necessary), consciously will volitional actions that they do not

objectively perform (conscious will is not sufficient), or feel

after the event that they have willed actions which were actually

forced or even made by the experimenter (conscious will can be

wrongly inferred, even when it logically cannot have existed).

(2) The subjective experience of agency or ownership of an action is

dissociable from objective agency. Lesions in the right parietal

cortex can produce syndromes in which the patient perceives

their hand to be under the control of someone else (Leiguardia et

al., 1993; Bundick and Spinella, 2000) or their limbs as not

belonging to them at all (Critchley, 1953; Nightingale, 1982;

Daprati et al., 2000).

(3) Libet’s famous experiments (Libet et al., 1982; 1983) show that

the brain activity coupled to a spontaneous action (i.e. the readi-

ness potential or RP) starts of the order of 350 ms before the sub-

ject reports having consciously willed the action. For many years

this highly repeatable and methodologically robust result was

taken to mean that voluntary acts are initiated pre-consciously.

Recently Pockett and Purdy (2010) showed that when the same

action is made not spontaneously but as the result of a specific

decision, the RP preceding the action shortens so that the RP

starts at about the same time as the reported willing of the action

— which on the face of it restores the possibility that conscious-

ness does directly cause actions. But by the time this experiment

hit the presses, experiments by others had shown that the time at

which the subject reports having willed an action is affected both

by events that take place after the action (Lau et al., 2007) and by

manipulation of feedback to the subject about the time at which

the action occurs (Banks and Isham, 2009). For example, if the

subject is led to believe that their individual actions happen pro-

gressively later than they actually did, the time at which these

acts were willed is also reported as being progressively later.

This latter group of experiments and others described in Section

5.1 strongly suggest that the initiation of voluntary actions is not

THE ELECTROMAGNETIC FIELD THEORY 197

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consciously experienced at all. The subject simply infers after

the event that they must have initiated their movement shortly

before they made it.

The conclusion forced by this confluence of evidence is that voluntary

actions are not initiated by consciousness. We infer that our conscious

thoughts directly cause our actions, but they actually don’t. Returning

to Objection 2, if consciousness does not cause behaviour, there is no

need to postulate that putatively conscious fields cause behaviour.

The conclusion that consciousness does not initiate or directly cause

behaviour relieves putatively conscious EM fields of any requirement

to cause the firing of behaviour-initiating neurons. Fortuitously, it also

allows development of an answer to Objection 3.

Objection 3

The third objection is that the EM field theory of consciousness as it

stands consists of little more than a bare statement of the idea that con-

sciousness is some kind of electromagnetic pattern generated by

brains. The idea has not been developed or elaborated enough even to

specify what distinguishes conscious EM fields from unconscious EM

fields, let alone what distinguishes the fields of cognitive thoughts

from those of the various sensory modalities like hearing, touch, or

vision, what makes one modality of sensory experience different from

another, or what separates the plethora of different experiences within

one sensory modality. Without at least an attempt at such specifica-

tion, the EM field theory fails to rise above the vagueness that

characterizes both psychoneural identity theory and functionalism.

Answer to Objection 3

The answer to Objection 2 now provides a lever with which to prise

open the question of what distinguishes the brain-generated EM fields

that do underpin conscious experiences from those that don’t. The

answer to Objection 2 tells us that brain activity underpinning the ini-

tiation of movements is not associated with conscious experiences. It

is clear apriorithat spatial patterns of local field potentials are criti-

cally dependent on neuroanatomy, specifically cytoarchitectonics. So

all we need do is ask what is different about the cytoarchitectonics of

areas that subserve the initiation of movements. Surprisingly, the

answer is clear-cut and stunningly simple. Unlike almost all other

areas of the neocortex, motor areas lack a layer 4. The next section

explains how this creates a particular 3D pattern of LFPs, which may

now be postulated to be necessary (though clearly not sufficient) for

conscious experience.

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2. Generation of Local Field Potentials

and Effect of Missing Layer 4

In order to appreciate the hypothesis proposed in this paper, it is nec-

essary first to understand the mechanism by which the fields referred

to by the EM field theory of consciousness are generated by the brain.

Importantly, these fields are different from the hypothetical ‘figure

currents’ whose existence was proposed by Köhler (1920; 1929;

1938; 1940) and experimentally disproved by Lashley (Lashley and

Semmes, 1951) and Sperry (Sperry et al., 1955) sixty years ago.

Rather, the electromagnetic patterns of the modern EM field theory of

consciousness are nothing more exotic than spatial patterns of local

field potentials (LFPs).

LFPs are easily measured extracellular electrical events that are

generated by the synchronous activity of a large number of chemical

synapses on cortical pyramidal neurons. The main factor permitting

LFP generation is the spatial alignment of pyramidal cell apical den-

drites. In the neocortex of mammalian brains, the cell body of each

pyramidal cell is located in one of six histologically distinguishable

layers which stack on top of one another from the inside of the cortex

(layer 6) to the outside (layer 1). The long apical dendrite of each

pyramidal cell extends radially in a more or less straight line from the

cell body towards the surface of the brain, in most cases ending in a

tuft in layer 1, just below the pia mater. In layer 1, both cortico-cortical

axons from other regions of the cortex and thalamo-cortical axons

from M-type cells in thalamus (Jones, 2007; Rubio-Garrido et al.,

2009) make excitatory chemical synapses on the pyramidal cell apical

dendrites. Figure 1 shows diagrammatically how the activation of

such synapses produces LFPs.

In step 1, vesicles of chemical neurotransmitter are released from

the presynaptic axon terminal into the synaptic cleft and bind to recep-

tors on the apical dendrite of the pyramidal cell. In step 2,ion channels

open and positive ions flow into the dendrite. The influx of positive

ions leaves a transient negativity in the extracellular fluid outside the

dendrite. If enough synapses on enough neighbouring dendrites fire

synchronously, this transient extracellular negativity achieves an

amplitude of anything up to tens of mV, and is called a population epsp

(Figure 2). In neocortical layer 1, where the synapses in question are

located, the population epsp is negative-going (upper part of step 2

Figure 1; Figure 2). However, the associated intracellular positivity in

the dendrite essentially has to go somewhere, so to complete the circuit,

positive ions more or less simultaneously flow out of the pyramidal cell

THE ELECTROMAGNETIC FIELD THEORY 199

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in the region of the pyramidal cell body, producing a positive-going

population epsp at that level (lower part of step 2 Figure 1; Figure 2). If

the associated intracellular epsps are large enough to trigger action

potentials at the initial segment of enough pyramidal cell axons, a rel-

atively small and brief population spike appears in the middle of the

population epsps (Figure 2).

200 S. POCKETT

Figure 1. Diagrammatic representation of the generation of LFPs (local

field potentials).

Figure 2. LFPs in neocortex.

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This general mechanism of LFP production was worked out for

hippocampal LFPs about 40 years ago (e.g. Bliss and Lømo, 1973)

and is well enough accepted to have entered various neuroscience

textbooks (e.g. Bindman and Lippold, 1981; Kandel et al., 1991).

Figures 1 and 2 illustrate two important facts about LFPs:

(1) LFPs are largely synaptic potentials, generated by the action of

excitatory chemical synapses. Action potentials have little effect

on the shape of LFPs. This latter fact has been noted since the

earliest studies (Bremer, 1938; 1949; Eccles, 1951) and may well

be explained (Bédard et al., 2004) by the strong low-pass filter-

ing properties of cortical tissue, which are probably due to signif-

icantly non-homogeneous extracellular resistance (see Section

5.5.1).

(2) LFPs always come in pairs: one negative-going transient around

the synapses and one positive-going transient outside another

region of the cell. These positive-negative pairs are conveniently

modelled as dipoles (right hand side of Figure 2).

The EM field theory of consciousness proposes that conscious fields

are distinguished from different conscious fields on the one hand —

and from completely non-conscious fields on the other — by the

three-dimensional patterns in which these dipoles are arranged.

One anatomical fact which is especially important in the context of the

hypothesis presented here is that in neocortical layer 4 there are virtu-

ally no pyramidal cell bodies. Layer 4 consists mainly of stellate cells,

which receive input from C-type cells in the thalamus (Jones, 2007).

THE ELECTROMAGNETIC FIELD THEORY 201

Figure 3. Sensory input to layer 4 does not generate measurable LFPs.

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Since the dendrites of stellate cells are not spatially aligned but extend

from the cell body in all directions, the dipole charges generated by

synaptic activity on stellate dendrites tend to cancel each other out.

Therefore, activity in layer 4 is very likely (although thisquestion has

not yet been investigated experimentally) not to generate any

measurable LFPs (see Figure 3).

3. The Hypothesis:

A Spatial Feature Diagnostic of Conscious EM Fields

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. 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. A 3D model of

such fields is shown in Figure 4.

According to this hypothesis, the main distinguishing feature of con-

scious fields is the neutral layer in the middle of the field pattern (Fig-

ure 4 and Figure 5A). Many brain-generated EM fields that are not

conscious will be similar, except that they will lack the neutral layer

(Figure 5B).

202 S. POCKETT

Figure 4. 3D model of conscious field. Grey layer in middle of column 1 is

neutral.

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At this point, two secondary hypotheses can also be foreshadowed

regarding the characteristics distinguishing (a) different modalities of

conscious experience and (b) different experiences within any given

modality:

(a) On the axis radial or perpendicular to the surface of the cortex,

the putatively conscious patterns are most affected by the laminal

locations of contributing pyramidal cell bodies, as described in

Section 2. In humans, the overall thickness of the cerebral cortex

varies between 1mm and 4.5 mm and thereare large regional dif-

ferences in the relative thickness of each of the six cytoarchitec-

tonic layers (Campbell, 1905; Brodman, 1909; Fischl and Dale,

2000). In line with the well accepted association of various cyto-

architectonically defined areas with particular sensory and cog-

nitive functions (Campbell, 1905; Brodman, 1909) it is likely

that variations in the radial structure of LFP patterns will distin-

guish different kinds or modalities of conscious experience.

(b) On the axes tangential to the surface of the cortex, some con-

sciousness-related EM patterns exist with spatial frequencies in

the 1–3 mm range (Pockett et al., 2007). This spatial frequency

suggests that the patterns are underpinned by variations in the

activity of neighbouring cortical columns (Mountcastle, 1957;

1997; Hubel and Wiesel, 1963; Abeles and Goldstein, 1970;

Swindale, 1990; Horton and Adams, 2005; Innocenti and

Vercelli, 2010). It is likely that differences in these tangential

THE ELECTROMAGNETIC FIELD THEORY 203

Figure 5. Hypothesized distribution of electric charge in brain-generated

fields that are (A) conscious and (B) non-conscious (one example from

many possibilities). Roman numerals to left indicate cortical layers.

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patterns — i.e. differences in the degrees of positivity/negativity

between columns 1, 2, 3, 4, and 5 in Figure 4 — will distinguish

different individual experiences within a given modality.

These two secondary hypotheses will not be developed further in the

present paper, which will concentrate on the main hypothesis.

4. Predictions of the Main Hypothesis

The main hypothesis proposed here gives rise to a number of testable

predictions.

(1) Any area of brain that can generate EM fields with the hypothe-

sized structure might or might not produce conscious experi-

ences. Any area of brain that cannot generate EM fields with the

hypothesized structure will not produce conscious experiences.

(2) Conscious sensory experiences will not be generated during the

first, feedforward pass of peripheral activity through the primary

sensory cortex. Recurrent or feedback activity to the primary

sensory cortex from other regions of cortex will be required.

(3) One manifestation of this requirement for feedback activity will

be a correlation of consciousness with the firing of action poten-

tials by particular cells in regions downstream from the primary

sensory areas.

(4) Another manifestation of the requirement for feedback activity

will be synchronization during the feedback of activity in these

downstream areas and activity in the primary sensory cortex.

(5) Imposition of external EM fields which may or may not vary tem-

porally, but spatially are unpatterned, will have no effect on con-

scious experiences. In the terminology of physics, there will be

no coupling between biological and external fields. The biologi-

cally generated spatial pattern defining the conscious experience

will simply ride on top of the spatially homogeneous external

field, like a boat on an ocean.

(6) Imposition of external EM fields that are spatially patterned (in

such a way that they do couple with the biologically generated

fields) will affect consciousness. Specifically, imposition of an

external field that is inversely patterned — one positive surface

layer and two deeper negative layers, each with a strength per-

fectly matched to that of the biologically generated inverse pat-

tern — will cancel the biological field and thereby obliterate the

relevant conscious experience.

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(7) Prevention of the occurrence of LFPs in the relevant areas with-

out disruption of the underlying synaptic activity will prevent the

relevant conscious experiences.

Existing neurophysiological evidence relating to these predictions

and proposals for testing of predictions that are not currently sup-

ported by any existing evidence are given in Section 5.

5. Exisiting Evidence and Proposed Tests

5.1 Any area of brain that can generate EM fields with the hypo-

thesized structure might or might not produce conscious exper-

iences. Any area of brain that can not generate EM fields with the

hypothesized structure will not produce conscious experiences

Evidence relating to this prediction can be studied in two parts.

5.1.1 Any area of brain that can generated EM fields with the

hypothesized structure might or might not produce conscious

experiences

At this stage, the idea that any area of brain gives rise to the hypothe-

sized EM pattern is yet to be tested. The fact that LFPs are negative-

going around excitatory synapses and positive-going around the cor-

responding cell bodies has been experimentally validated for

hippocampal pyramidal cells (e.g. Bliss and Lømo, 1973), and dia-

grams depicting a similar situation as occuring in 6-layered neocortex

certainly appear in neuroscience texts (e.g. Bindman and Lippold,

1981; Kandel et al., 1991). But the hypothesis here suggests that EM

fields with the structure shown in Figures 3, 4, and 5 might appear

only in the brains of conscious subjects. It is certainly possible to mea-

sure LFPs in waking animals (e.g. Bliss and Gardner-Medwin, 1973;

Wiest and Nicolelis, 2003; Dejean et al., 2007; Eliades and Wang,

2008; Roš et al., 2009; Rolston et al., 2009) and chronic intracortical

recording is standard even in humans (e.g. Pockett and Holmes,

2009). But to date, no such measurements have been done in a way

that is specifically motivated by the present hypothesis. Thus, to my

knowledge there are presently no reports on the simultaneous mea-

surement of peripherally-induced LFPs at a series of depths in the

6-layered neocortex of waking mammals. While technically challeng-

ing, it should be relatively straightforward in principle to make such

recordings and thereby see whether the hypothesized EM pattern does

appear in the brains of waking mammals, and whether it degrades or

disappears when the subject is anaesthetized or otherwise loses

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consciousness. Microelectrodes would have to be positioned in corti-

cal layers 1, 2/3, 4, and 5/6; probably in small animal subjects initially,

so that dye spots could be deposited after recording to confirm elec-

trode location. The pick-up range of an electrode is reported to depend

on its size (Bindman and Lippold, 1981), so in order on the one hand

to avoid missing the neutral layer (by contaminating records taken in

putatively neutral layer 4 with pick-up from the adjacent putatively

negative layers 3 and 5), and on the other hand to record LFPs at all

(see Section 5.4.1), it would be necessary to use microelectrodes of a

size commensurate with a pick-up range of the order of 50–100 µm.

This requirement could be fulfilled by the positioning of multitrodes

consisting of 10–12 glass microelectrodes, each of whose shafts was

bent so that the tips were in the same axis, with tips spaced ~200 µm

apart, each tip with a diameter of ~5 µm and an impedance of

0.5–3 MW. Alternatively a multicontact metal electrode with similar

characteristics could be used.

5.1.2 Any area of brain that cannot generate EM fields with the

hypothesized structure will not produce conscious experiences

Of course, it is not a logical requirement of this hypothesis that the

postulated EM pattern will fail to appear in unconscious subjects. The

pattern in question is proposed to be necessary but not sufficient for

consciousness, so if it did appear in unconscious brains one could

always argue that consciousness depends on some additional, yet-

unrecognized factor that is not present in unconscious brains. How-

ever, the claim that the proposed structure is necessary for conscious-

ness does make the very strong prediction that brain areas which

cannot generate this spatial EM pattern will not be able to produce

consciousness. In order to produce the EM field structure hypothe-

sized here as being conscious, essentially a 6-layered architectonic

structure is necessary. So the second half of Prediction 1 boils down to

a prediction that areas which do not have 6-layered architectonicswill

not have the capacity to generate consciousness experiences. Is this

supported by available evidence?

Most areas of the neocortex do exhibit the necessary 6-layered

structure. According to Fatterpekar et al. (2002), only Brodman Areas

4, 6, 8, part of 11, 24, 25, 26, 28, 29, 30, and 33 were classified by von

Economo (1925; 1927) as ‘agranular’, which means they do not have

a layer 4. These agranular areas are all concerned with motor function

(Porter and Lemon, 1993; Shipp, 2005). Outside the neocortex, the

putatively more ancient allocortex — i.e. hippocampus and one region

of what is loosely termed the olfactory cortex (Mesulam and Mufson,

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1982) — has only 3 layers. The cerebellum is highly structured, but

does not have pyramidal cells like those in the cortex at all (Eccles et

al., 1967). Subcortical structures such as the thalamus, basal ganglia,

and amygdala do not show any layering comparable with that of the

cortex. So basically, the present hypothesis predicts that most areas of

the neocortex might or might not be capable of producing conscious

experiences. The only areas in the brain that are predicted to be defi-

nitely incapable of producing conscious experiences are BA4, BA6,

and BA8 (the primary motor and premotor cortices), several medial

areas also concerned with motor function, the cerebellum, the hippo-

campus, one part of the general area including the olfactory cortex,

and all subcortical structures.

These are very specific predictions. Are they supported by the

available evidence? With regard to the primary motor and premotor

cortex, the answer is clearly yes. When Desmurget et al. (2009)

directly stimulated the cortex of awake patients undergoing brain sur-

gery, stimulation of parietal regions elicited subjective reports of a

conscious intention or desire to move the relevant part of the body,

which escalated with stronger stimuli to a belief that a movement had

actually been made, even though no electromyographic activity was

detectable. However, stimulation of the region incorporating BA4,

BA6, and BA8 elicited no reports of any conscious experience and in

fact firm denials that any bodily movement had taken place, even

when the stimuli were so strong that movement of the relevant body

part was clearly observed by the experimenters. Parietal regions are

thought to generate conscious intentions to move at some time in the

near future, while the premotor cortex and its associated subcortical

structures are thought to underpin movement initiation (Pockett,

2006). Hence, the physiological results reported by Desmurget et al.

(2009) are reinforced by a wide range of psychological results show-

ing that people are not consciously aware of the initiation of their own

voluntary movements (Wegner, 2002; Pockett, 2004; Aarts et al.,

2005; Pockett et al., 2006; Lau et al., 2007; Banks and Isham, 2009;

Kühn and Brass, 2009, Rigoni et al., 2010). So the prediction of the

present hypothesis that precentral motor areas should not generate con-

scious experiences appears to be well supported by available evidence.

The present hypothesis also predicts that a number of other brain

areas will be incapable of generating conscious experiences. These

areas include the cerebellum, hippocampus, olfactory cortex, and all

subcortical structures. To take these in turn, the cerebellum is widely

understood to underpin unconscious control of movements (e.g.

Jeannerod, 2006). The hippocampus certainly has something to do

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with the laying down of potentially conscious long-term declarative

memories, but it is not the site where such memories are stored

(Scoville and Milner, 1957; Stefanacci et al., 2000; Corkin, 2002).

The idea that the hippocampus may represent a cognitive map

(O’Keefe and Nadel, 1978) suggests that it may subserve some form

of spatial consciousness, but initial formulations of this cognitive map

theory have recently been repudiated (Hardt and Nadel, 2009); so at

this stage there is no evidence suggesting that the hippocampus gener-

ates conscious experiences. With regard to olfaction, it is not yet clear

exactly where conscious olfactory sensations (or indeed any con-

scious sensations) are generated, but Mesulam and Mufson (1982)

show that many parts of the general region labelled olfactory cortex

do have 6-layered architectonics. The neural correlates of emotion

have in the past been studied primarily in the context of the neuro-

transmitters involved and their effects on various subcortical struc-

tures (Panksepp, 1998; Nestler and Malenka, 2004). However, 6-

layered cortex does participate in the networks that incorporate these

subcortical structures and there is evidence for the involvement of

frontal and temporal grey matter in the primary emotional sensation of

cocaine-induced euphoria, for example (Hitri et al., 1994; Bartzokis

et al., 2004; Dong et al., 2005).

So to summarize, the available evidence fails to disprove the cur-

rent hypothesis with regard to any of the brain areas predicted to be

unable to generate conscious experiences.

5.2 Conscious sensory experiences will not be generated during

the first, feedforward pass of peripheral activity through the

primary sensory cortex. Recurrent or feedback activity to the

primary sensory cortex from other regions of the cortex will be

required

This prediction arises because feedforward thalamic input from the

peripheral sense organs initially reaches the cortex by way of the stell-

ate cells of layer 4 (e.g. Salami et al., 2003), which generate only very

small LFPs because there is no anatomical alignment of multiple

stellate cell dendrites (see Figure 3). As explained above, LFPs of any

significant size are generated only by the activity of feedback circuits,

which synapse largely in layer 1 and generate LFP dipoles extending

between layer 1 and layers 2/3 or 5/6 in the neocortex.

So does existing evidence suggest that feedback or recurrent activ-

ity is necessary for consciousness? At least with regard to the visual

system, the answer is now a definitive ‘yes’. After some initial

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controversy about whether or not V1 activity is a neural correlate of

visual consciousness at all (Crick and Koch, 1995a,b; Pollen, 1995),

evidence has steadily accumulated that consciousness does not corre-

late with the first, feedforward passage of activity through V1, but

does correlate with feedback to V1/V2 from ‘higher’ visual areas,

100–200 ms after the external visual stimulus (Lamme et al., 1998;

Lee et al., 1998; Pollen, 1999; 2003; 2008; Lamme and Roelfsema,

2000; Pascual-Leone and Walsh, 2001; Supèr et al., 2001; Juan and

Walsh, 2003; Ro et al., 2003; Juan et al., 2004; Lamme, 2004;

Silvanto et al., 2005; Fahrenfort et al., 2007; Koivisto et al., 2010;

Thielscher et al., 2010). Most of this evidence comes from experi-

ments in which various areas of the brain are temporarily inactivated

using TMS (Transcranial Magnetic Stimulation) at various times after

an external stimulus. For example, Boyer et al. (2005) show that

blindsight can be induced by brief inactivation of V1 at 100 ms post-

stimulus, and Silvanto et al. (2005) report that consciousness of

motion can be ablated by TMS delivered to any of (i) V1 at 40–60 ms,

(ii) V5/MT at 60–80 ms, or (iii) V1 at 80–100 ms post-stimulus.

5.3 One manifestation of this requirement for feedback activity

will be a correlation of consciousness with the firing of action

potentials by particular cells in regions downstream of the

primary sensory areas

Figure 2 shows that the firing of action potentials by the pyramidal

cells that directly generate our putatively conscious EM fields has lit-

tle effect on those fields. Population spikes may sculpt LFP patterns

somewhat, but the firing of individual cells in these regions does not

have much to do with the patterns we are interested in. However, in

order to generate the feedback activity that produces the LFP patterns

of interest, neurons must certainly fire in regions where the feedback

originates. Some of the feedback in question will come from M-type

cells in the thalamus, but much of it will arise in various far-flung

regions of the cortex. So Prediction 3 boils down to the suggestion that

recording the firing of individual cortical cells will not necessarily

show correlations between consciousness and firing in regions where

consciousness arises. Rather, it will show correlations between con-

sciousness and regions where the feedback necessary to generate a

hypothetically conscious LFP pattern arises.

This prediction is perhaps supported by a number of reports that

conscious events correlate best with the firing of individual neurons in

regions well outside the primary and secondary sensory areas. For

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example, various specific visual percepts have been correlated with

the firing of single cells in the medial and inferior temporal cortices

and around the superior temporal sulcus (Logothetis and Schall, 1989;

Leopold and Logothetis, 1996; Scheinberg and Logothetis, 1997;

Krieman et al., 2000; Quian Quiroga et al., 2005). The most convinc-

ing of these experiments concerns binocular rivalry, a paradigm in

which the information presented to each eye of the subject is different

enough so that it cannot be fused into one binocular image but is seen

as two competing images alternately, one percept replacing the other

spontaneously every few seconds. Logothetis and colleagues

arranged for this situation to occur in waking monkeys and correlated

the firing of single cells in various regions of brain with which of the

two figures the monkey reported seeing. In areas V1/2, V4, and V5,

between 60% and 80% of cells depending on the area continued to

respond to their preferred stimulus regardless of whether it was per-

ceived or not. However, in areas IT (inferior temporal cortex) and STS

(upper and lower banks of the superior temporal sulcus) about 90% of

cells reliably predicted the perceptual state of the animal, by firing

only when their preferred stimulus was perceived. Because the exact

moment at which the percept switched was not accessible, these

experiments did not distinguish between early and late firing in V1/2.

In the context of the present hypothesis, the results could be inter-

preted as indicating that most of the firing in early visual areas sub-

serves early feedforward transmission (which does not correlate with

perception), while firing in IT and STS initiates the feedback that is

necessary for perception.

5.4 Another manifestation of the requirement for feedback activity

will be a transient synchronization during the feedback of activity

in these downstream areas and activity in the primary sensory

cortex

Coherence or synchrony has been observed as a necessary (though not

sufficient) correlate of consciousness for many years now, but so far

this observation has not been transparently explained in terms of its

being a necessary part of any specific theory of consciousness. The

present hypothesis is that certain LFP patterns are identical with con-

sciousness. There are at least two distinct ways in which synchrony is

important in the generation of LFPs.

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5.4.1 Synchronous firing of many synapses required for

production of LFPs

First, the synchronous firing of many cortico-cortical or thalamo-

cortical axons is necessary to produce measurable LFPs at all. Electro-

physiological potentials are measured as the voltage drop across a

particular resistance. With intracellular recording, the relevant resis-

tance is that of the cell membrane. With extracellular recording, it is

the resistance of the extracellular fluid, which in most locations is

very low compared with the resistance of the cell membrane. By

Ohm’s Law, a given current flow will produce a smaller voltage across

a smaller resistance, so the amplitude of an extracellular epsp is much

smaller than that of an intracellular epsp: extracellular epsps due to

activation of a single pyramidal cell are (probably) unmeasurably

small. In order to produce a measurable LFP, many individual extra-

cellular epsps have to occur close to each other in both space and time.

In fact the extracellular resistance in the neocortex is probably not uni-

form, but acts to impose a low-pass filter on the electromagnetic prod-

ucts of neural activity (Bédard et al., 2004). This means that the

relatively low-frequency fluctuations of epsps are measurable at much

greater distances from their sites of generation than is the case for the

faster action potentials, which allows spatial summation of epsps over

a relatively wide area.

The upshot of all this is that synchronous feedback onto the apical

dendrites of a number of adjacent pyramidal cells results in more sum-

mation and thus larger LFPs. The hypothesis presented in the present

paper predicts that a certain minimum amplitude of LFPs is necessary

for conscious experience. This prediction is supported by the fact that

perception during binocular rivalry is clearly correlated with more

intense spatiotemporal electromagnetic patterns (Tononi et al., 1998).

Thus synchronous feedback onto many adjacent pyramidal dendrites

is a necessary correlate of consciousness according to our hypothesis.

5.4.2 Long-range synchrony as an indicator of feedback activity

A second way in which synchrony is important for the generation of

LFPs is that synchronous neural activity between far-flung regions of

the cortex serves an indicator of the presence of active feedback.

Some difficulty arises with regard to the best method of measuring

feedback-related synchrony. As pointed out above, single-cell tech-

nologies certainly pick up action potentials in the regions where feed-

back originates, but it is far from clear that the cells receiving the

feedback — the cells of interest to the present hypothesis — will nec-

essarily fire as a result of feedback to them. Reverberatory activity has

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to stop sometime, and perhaps the appearance in ‘early’sensory areas

of [conscious] feedback-generated LFP patterns is the normal end-

point of sensory input. On this reasoning it is possible that single cell

recording techniques are better suited to the measurement of feedfor-

ward-related synchrony (Roelfsema et al., 1997; Singer et al., 1997)

than they are to the measurement of feedback-related synchrony.

However, EEG-based phase synchrony measurements (which

examine the accumulated signature of multiple LFPs rather than that

of action potentials per se) do come with their own set of pitfalls. A

major one is related to the inevitable use of a recording reference that

is itself active to some varying degree (Fein et al., 1988; Pockett et al.,

2009). Such problems can easily lead to erroneous conclusions: for

example, one widely cited early report that long-distance synchrony

correlated with face perception (Rodriguez et al., 1999) was later

shown to be repeatable only if recordings were made against a nose

reference contaminated with microsaccades (Trujillo et al., 2005).

However, pace such difficulties, long-distance phase synchrony does

seem to be necessary (Lutz et al., 2002; Melloni et al., 2007; Gaillard

et al., 2009; Tallon-Baudry, 2009), albeit not sufficient (Pockett and

Holmes, 2009; Luo et al., 2009), for conscious perception.

In summary, Prediction 4 of the current hypothesis does appear to

be supported by what relatively little evidence is available.

5.5 Imposition of external EM fields that may or may not vary

temporally, but spatially are unpatterned, will have no effect on

conscious experiences

Life in the twenty-first century involves constant exposure to external

electromagnetic fields. Microwave ovens, wireless LAN networks,

radio and TV broadcasts, cell phones, and a host of other sources

bathe us continuously in EM oscillations in the GHz and MHz ranges.

In a frequency range more relevant to the oscillations generated by

brains, not only high voltage electricity transmission lines but also

such common appliances as hair-dryers routinely supply respectable

levels of 50 or 60 Hz electromagnetism. MRI machines generate enor-

mous magnetic fields, and apart from the occasional visual scintilla-

tion caused by stimulation of the visual cortex in MRI magnets, none

of it has any effect on consciousness.

This is entirely as predicted by the EM field theory of conscious-

ness. According to this theory, the defining feature of fields that are

conscious is not the frequency with which they wax and wane, but

their 3D spatial pattern. All of the aforementioned environmental EM

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fields are spatially unpatterned. One result of their spatial homogene-

ity is that these environmental fields have no effect on the spatial EM

patterns involved in the present theory. In the terminology of physics,

there is no coupling between external and biological fields. The bio-

logically generated spatial pattern defining the conscious experience

simply rides on top of the spatially homogeneous external field, like a

boat on an ocean.

Another, perhaps less fortunate, result of the spatial homogeneity of

common EM fields is that so far there has been no technology-driven

incentive to develop signal processing techniques that would allow

the mathematical description and manipulation of spatial EM patterns.

Development of such techniques will be essential to the advancement

of the EM field theory of consciousness.

5.6 Imposition of external EM fields that are spatially patterned,

in such a way that they do couple with the biologically generated

fields, will affect consciousness

One specific example of this prediction is that imposition of an

inversely patterned external field — one surface positive layer and

two deeper negative layers, each with a strength perfectly tuned to that

of the biologically generated pattern — will cancel the relevant bio-

logical field and thereby obliterate the relevant conscious experience.

This prediction is certainly testable in principle, but at present not

enough is known either about the precise patterns underlying any

given conscious experience or practical means of generating such pat-

terns using hardware to make it testable in practice.

5.7 Prevention of the occurrence of LFPs in the relevant areas

without disruption of the underlying synaptic activity will prevent

the relevant conscious experiences

However, Prediction 7 — that disruption of the LFPs underpinning a

putatively conscious EM field pattern should disrupt the conscious

experience in question — certainly is testable. If the means by which

the LFPs were disrupted simply involved preventing the synaptic

activity that generated the LFPs, the experiment would fail to distin-

guish between the neural identity hypothesis and the electromagnetic

field hypothesis. In order to test the electromagnetic field hypothesis,

it would be necessary to disrupt LFPs without disrupting the underly-

ing synaptic activity. The most straightforward way of achieving this

would be to voltage clamp the LFPs.

THE ELECTROMAGNETIC FIELD THEORY 213

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A schematic showing the principle of how a two-electrode voltage

clamp might be used to clamp a negative-going population epsp in

layer 1 of the neocortex is shown in Figure 6. The recording amplifier

measures the difference between electrical events at the recording

electrode and a virtual earth — the result is shown as the negative-

going population epsp (with its associated population spike). The

feedback amplifier then makes a real-time comparison between this

waveform and a command voltage, which in the present case is set to

the virtual earth. Finally current is fed to the current passing electrode

in such a way that the population epsp is neutralized as it occurs. In

practice, the whole sequence of events would probably be best accom-

plished using a single microelectrode which alternates between mea-

suring and passing current — the discontinuous single electrode

voltage clamp technique popularized by Finkel and Redman (1984). It

would obviously be impossible to achieve much of a space clamp in

such an experiment — only the region immediately around the current

passing electrode would be clamped — but this could actually be an

advantage rather than a limitation because it would allow precise dis-

section of the region of most importance in the extracellular electric

field pattern. Optimally at least two independent clamps would be

applied, to control the extracellular voltages in limited regions of both

214 S. POCKETT

Figure 6. Schematic showing principles involved in voltage clamping LFPs.

For personal use only -- not for reproduction

layer 2/3 and layer 5/6; but according to the present hypothesis,

clamping even one of these areas should disrupt the overall pattern

enough to disrupt the conscious experience.

At present it is far from clear exactly where in the brain the neural

correlates of any given sensory experience are to be found, but the evi-

dence cited in Section 5.2 suggests that the primary sensory area

related to the sensation evoked by any given external stimulus would

be a good place to start. Since most of the ion channels linked to neu-

rotransmitter receptors are not voltage sensitive, controlling the exter-

nal voltage in this region should produce relatively little effect on the

synaptic action that normally generates the LFPs being controlled —

in other words, the synapses should largely continue to work nor-

mally. Whether or not this expectation was fulfilled could in any case

be measured directly, by measuring the current that has to be passed in

order to clamp the extracellular voltage.

Experimental support for the prediction that disruption of con-

scious experiences can be achieved by disrupting LFP patterns with-

out affecting the underlying synaptic activity that produces those

patterns would provide (a) confirmatory evidence for the present

hypothesis, (b) strong support for the wider EM field theory of con-

sciousness, and (c) a potentially useful clinical method of controlling

unwanted conscious experiences like chronic pain. This latter out-

come would provide ethical justification for performing the voltage

clamping experiment in human subjects, who could report verbally

(rather than via pre-trained behavioural actions) on the presence or

absence of particular conscious experiences. However, preliminary

results from animal experiments would probably be necessary to

establish both the technical details and the viability of the test as a

whole.

6. Discussion

The hypothesis outlined here has four important features.

First, as a hypothesis it sits squarely within a larger theory, the elec-

tromagnetic field theory of consciousness.

The only theories of the nature of consciousness that compete for

the same intellectual ground as the electromagnetic field theory are (a)

psychoneural identity theory, (b) functionalism, and (c) various theo-

ries that invoke quantum mechanical formalisms. With regard to (a)

and (b), it is difficult to find any very specific statement of the modern

version of the psychoneural identity theory, but its name implies the

basic tenet that psyche is identical with neurons — or neural activity,

or some types of neural activity. Probably the most succinct published

THE ELECTROMAGNETIC FIELD THEORY 215

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statement of the idea is Crick’s famous paraphrase of Alice in Won-

derland: ‘You’re nothing but a pack of neurons’ — or, slightly more

precisely ‘[You are] no more than the behavior of a vast assembly of

nerve cells and their associated molecules’(Crick, 1994). Already the

insertion of the phrase ‘the behavior of’ into this latter definition

seems to make The Astonishing Hypothesis (and, inasmuch as the two

can be equated, psychoneural identity theory) uncomfortably similar

to the dogma of functionalism, which says ‘consciousness is a pro-

cess, not a thing’. The electromagnetic field theory of consciousness

blurs this apparent distinction even further, by proposing that con-

sciousness is not a brain process per se, but an electromagnetic prod-

uct of a subset of brain processes — thereby reifying or providing a

physical basis for functionalism’s abstract ‘process’, while at the same

time removing the intuitive difficulties associated with equating func-

tioning neurons per se with consciousness, as psychoneural identity

theory apparently does. With regard to (c), the relationship between

the electromagnetic field theory and quantum mechanical or quantum

field theories of consciousness is presently moot. Several advantages

enjoyed by EM field theory, which QM theories are presently hard

pressed to match, are enumerated below.

The second important feature of the present hypothesis is that it

draws together and provides a coherent explanation for a variety of

empirical observations that otherwise appear unconnected. These

observations include (i) the long-recognized regional variations in

cytoarchitectonics; (ii) the fact that consciousness takes time to

develop; (iii) the fact that recurrent activity is necessary for con-

sciousness; (iv) the importance to consciousness of various kinds of

synchrony; (v) the fact that spatially unpatterned external EM fields

do not affect consciousness; and last but not least, (vi) the recently

recognized inability of humans to perceive the initiation of their own

voluntary actions.

A third feature of the present hypothesis is that it provides a trans-

parent predictor of the circumstances under which consciousness is

possible. Basically, the present hypothesis predicts that nervous sys-

tems (or parts of nervous systems) that do not exhibit 6-layered

cytoarchitectonics will not be capable of generating consciousness.

This provides a basis for answering in principle the vexed question of

whether or not any given animal species is consciousness-capable.

The fourth and arguably most important feature of the present

hypothesis is that it is directly testable. Experimental requirements for

performing the critical tests are outlined in Sections 5.1.2, 5.6, and

5.7. In particular the prediction of the hypothesis that is tested by the

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experiment proposed in Section 5.7 — that alteration of the field and

only the field which goes with a particular conscious experience will

alter the experience — converts the main hypothesis described in this

paper from a merely correlative to a completely mechanistic con-

struct. If this prediction is supported by the proposed experiment, the

simplest explanation will be that the field is the conscious experience.

Of course, if the experiment in Section 5.7 did produce the pre-

dicted result, it would remain logically possible that the EM field was

only a correlate of something else, something completely unknown —

perhaps a dualist phenomenon, inaccessible to science and ultimately

unknowable. But science basically works by means of Occam’s razor

— the simplest explanation is generally accepted, at least for the time

being, as the right one. The argument that something more compli-

cated is the real truth could be made about absolutely anything that is

presently accepted as scientific fact. Perhaps things are not as they

seem. Perhaps there is a completely different explanation, about

which we don’t have a clue. Well yes, perhaps. But it is also possible

that the desire to follow this logically impeccable but scientifically

untenable line of reasoning may be at least a partial explanation for

why philosophers have been hammering away at the mind–body

problem for the last 2,000-odd years with so little success.

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THE ELECTROMAGNETIC FIELD THEORY 223

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Toward the unknown: consciousness and pain

Article

Full-text available

Feb 2023

Richard Ambron

Studies of consciousness are hindered by the complexity of the brain, but it is possible to study the consciousness of a sensation, namely pain. Three systems are necessary to experience pain: the somatosensory system conveys information about an injury to the thalamus where an awareness of the injury but not the painfulness emerges. The thalamus distributes the information to the affective system, which modulates the intensity of the pain, and to the cognitive system that imparts attention to the pain. Imaging of patients in pain and those experiencing placebo and hypnosis-induced analgesia shows that two essential cortical circuits for pain and attention are located within the anterior cingulate cortex. The circuits are activated when a high-frequency input results in the development of a long-term potentiation (LTP) at synapses on the apical dendrites of pyramidal neurons. The LTP acts via α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors, and an anterior cingulate cortex–specific type-1 adenylate cyclase is necessary for both the LTP and the pain. The apical dendrites form an extensive network such that the input from serious injuries results in the emergence of a local field potential. Using mouse models, I propose experiments designed to test the hypothesis that the local field potential is necessary and sufficient for the consciousness of pain.

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Sep 2021
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The goal of this work is to compile the basic components for the construction of an electromagnetic field theory of consciousness that meets the standards of a fundamental theory. An essential cornerstone of the conceptual framework is the vacuum state of quantum electrodynamics which, contrary to the classical notion of the vacuum, can be viewed as a vibrant ocean of energy, termed zero-point field (ZPF). Being the fundamental substrate mediating the electromagnetic force, the ubiquitous ZPF constitutes the ultimate bedrock of all electromagnetic phenomena. In particular, resonant interaction with the ZPF is critical for understanding rapidly forming, long-range coherent activity patterns that are characteristic of brain dynamics. Assuming that the entire phenomenal color palette is rooted in the vibrational spectrum of the ZPF and that each normal mode of the ZPF is associated with an elementary shade of consciousness, it stands to reason that conscious states are caused by the coupling of the brain to a particular set of normal modes selectively filtered from the full frequency spectrum of the ZPF. From this perspective, the brain is postulated to function as a resonant oscillator that couples to a specific range of ZPF modes, using these modes as a keyboard for the composition of an enormous variety of phenomenal states. Theoretical considerations suggest that the brain-ZPF interface is controlled by altering the concentrations of neurotransmitters, placing the detailed study of the neurotransmitter-ZPF interaction at the center of future research activities.

Consciousness: Matter or EMF?

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FRONT HUM NEUROSCI

Johnjoe J Mcfadden

Conventional theories of consciousness (ToCs) that assume that the substrate of consciousness is the brain's neuronal matter fail to account for fundamental features of consciousness, such as the binding problem. Field ToC's propose that the substrate of consciousness is the brain's best accounted by some kind of field in the brain. Electromagnetic (EM) ToCs propose that the conscious field is the brain's well-known EM field. EM-ToCs were first proposed only around 20 years ago primarily to account for the experimental discovery that synchronous neuronal firing was the strongest neural correlate of consciousness (NCC). Although EM-ToCs are gaining increasing support, they remain controversial and are often ignored by neurobiologists and philosophers and passed over in most published reviews of consciousness. In this review I examine EM-ToCs against established criteria for distinguishing between ToCs and demonstrate that they outperform all conventional ToCs and provide novel insights into the nature of consciousness as well as a feasible route toward building artificial consciousnesses.

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Book

Dec 2022

Alfred Bennun

El efecto Doppler podría aplicarse a la conectividad neuronal direccional que implica un cambio en la frecuencia ν±Δν de la onda que se mueve en relación con la fuente de la onda, actuando sobre el distanciamiento del circuito neuronal. El orbital 1s del átomo de hidrógeno permite que el espín del electrón suba y baje para emitir a 18 cm del radical hidroxilo y 21 cm de hidrógeno atómico, que combinados forman agua. Esta línea espectral más fuerte del hidrógeno, presente en la Edad Oscura y detectada por radioastronomía desde las galaxias primordiales. Es también emitida por el agua de todos los tejidos, médicamente aplicada para estudios cerebrales, por resonancia magnética (MRI). Por lo tanto, una imagen oscilante del efecto Doppler de la dinámica de distanciamiento-acortamiento permite la conectividad neuronal por sus frecuencias de espectro de emisión. Por lo tanto, el ensayo de coherencia a escalas nanométricas o termodinámica de distanciamiento, equivalente a la fuerza de plasticidad del movimiento neuronal para la conectividad eléctrica. Por lo tanto, su medida de interpretación era equivalente al diálogo (crosstalk) entre neuronas y su elucidación se convirtió en un análogo a una sincronización a un nivel quántico. Las enzimas transmembrana generan la entalpía, acoplada al metabolismo de la glucosa y del clúster de agua (H2O)n=3.4. Los productos CO2 y agua como vapor se exhalan en la boca como entropía. Este modelo integrador permite una perspectiva conjunta de múltiples capas de la realidad, condicionada por la dimensión de la escala. Así, la métrica de la mecánica cuántica podría mostrar los marcos locales para la superposición del espacio y la simultaneidad. La relación termodinámica del cerebro entre las entradas de glucosa y el proceso de entalpía de la energía metabólica (calor), acoplado homeostáticamente a 36,6 ℃ a la ruptura de puente de H del clúster de agua, que en el flujo de líquido cefalorraquídeo (LCR) en los microtúbulos podría circular en estado líquido como dímeros (H2O~OH2) para disipar la entropía como vapor en la cavidad oral. Las capas múltiples a escala neuronal manifiestan el espín en función de la antena para la señalización de la dinámica de conectividad del axón, las dendritas, los microtúbulos y la tunelización. El espacio mielinizado es un sistema termodinámico cerrado, que eventualmente tiende al equilibrio entre entalpía y entropía, en el que la energía no puede producir trabajo. En un axón mielinizado, los Nodos de Ranvier permiten “saltar” de un nodo a otro, operando tramos no mielinizados como canales termodinámicamente abiertos. La termodinámica cuántica permite una secuencia repetitiva de los canales iónicos en el nivel nano de cerrado a abierto, cerrado a abierto, cerrar… Por lo tanto, se conserva un valor máximo de entalpía y la entropía se disipa fuera del sistema, manteniendo el nivel de potencial de acción en estado estacionario. Por lo tanto, los canales de iones podrían volver a suplir las concentraciones de Na+/K+ para la recuperación de una entalpía con una entropía disipativa fuera del sistema. Por lo tanto, una cinética de asociación multiplicativa mediante la sincronización de la emisión de fotones permite una señalización común para la coherencia funcional multineuronal. Este refuerzo es necesario para operar con un ruido casi nulo, para evitar la asincronía caótica. El efecto involucra una escala nanométrica de espacio y tiempo porque está mediado por fotones que se mueven en una fase líquida: 2.25109m/s (0.75 c). Por lo tanto, permitir crosstalk entre neuronas a una velocidad muy alta, integrando el tiempo operativo de los sistemas sincronizando la actividad de los receptores acoplados a la función activadora de la proteína G en las vías insulina/glutamatérgica y catecolaminérgica. El nanoespacio mantiene una alta tasa de colisiones moleculares, maximizando la afinidad a valores de saturación por encima de una concentración baja de hormonas, etc. Los cambios estructurales de las enzimas transmembrana acopladas al metabolismo de la glucosa y la ruptura del puente de H del clúster de agua acoplada podrían alcanzar una entalpía alta y la entropía residual en el sistema. Por lo tanto, las estructuras separadas en el nanoespacio podrían integrar más eficientemente su función, maximizando la conectividad entre las neuronas y los microtúbulos, para un flujo de entrada de sustrato y salida de productos de un sistema abierto operativo. Por lo tanto, el efecto de la insulina a nivel de tirosina quinasa estaría afectando simultáneamente todo el citoesqueleto neuronal del sistema de microtúbulos y el ciclo celular. La termodinámica inanimada del principio de reversibilidad microscópica por la estructura y función necesario para la vida, adaptando al nivel de la membrana un orden cinético vectorial superador de la reversibilidad. A nivel fisiológico celular NA-AC y la autofosforilación del receptor de insulina tirosina quinasa (IRTK) regulan la capacidad de respuesta a las hormonas de concentraciones iónicas, en función de los metabolitos quelantes. Así, un decrecimiento del Mg2+ produce AC desactivado al liberar ATP4- libre y activar IRTK, lo cual, permite una integración de la respuesta hormonal de ambas enzimas mediante controles iónicos. Este efecto podría reemplazar el control de feedback metabólico por carga de energía. En consecuencia, la respuesta hormonal máxima de ambas enzimas, para una concentración alta de Mg2+ y baja de ATP4- libre, permite una correlación con los efectos conocidos de la baja ingesta calórica, que aumenta el nivel de iones libres y podría elevar la esperanza de vida promedio.

The brain structures micro to nano space-time levels into the thermodynamics of an open-system

Book

Dec 2022

Alfred Bennun

The Doppler shift could be applied to directional neuronal connectivity involving change in frequency ν±Δν of wave that is moving relative to the wave source, acting over neuronal circuit distancing. The 1s orbital of the hydrogen atom allows the electron spin-flip up and down to emit radio emission at 18cm from hydroxyl radical and 21cm atomic hydrogen, which combined form water. This strongest spectral line of the hydrogen, present in the Dark Ages and by radio astronomy detected from primordial galaxies, is emitted by the water of all tissues, medically applied for brain studies, by magnetic resonance imaging (MRI). Hence, a Doppler Effect imaging of the distancing dynamics allows neuronal connectivity by their emission spectrum frequencies. Hence, the assay of nano scales coherence or distancing thermodynamics, equivalent to the plasticity strength of neuronal movement for electric connectivity. Therefore its interpreting measure an equivalent of crosstalk between neurons and its elucidation became an analog to a translation of this unknown process. The transmembrane enzymes generate the enthalpy, coupled to the metabolism of glucose and water cluster. The products CO2 and water as vapor are exhaled at the mouth as entropy. This integrative model allows a joint perspective of multiple layers of the reality, conditioned by scale dimension. Thus, the metrics of the quantum mechanics realm could show the locals frames for superposition of space and simultaneity. The brain thermodynamics relationship between inputs of glucose and the enthalpy process of metabolic energy (heat), coupled homeostatically at 36.6℃ to water cluster H-bond breakdown, which in the cerebrospinal fluid (CSF) flow in microtubules could circulate in a liquid state as dimers (H2O~OH2) to dissipate entropy as vapor in the oral cavity. The multi-layers at neuron scale manifest spin in antenna role to signal connectivity for axon, dendrites, microtubules and tunneling. Myelinated space is a thermodynamic closed system, which eventually tends to equilibrium between enthalpy and entropy in which free energy cannot produce work. At a myelinated axon the Nodes of Ranvier “jumps” from node to node operate the unmyelinated stretches as a nano open space-time system. Quantic thermodynamic allows a repetitive sequence at the nano level of close to open, close to open, close … Hence, a maximal value of enthalpy is conserved and entropy became dissipated outside the system, maintaining the action potential level in steady state. Hence, the ions channels could refill the Na+/K+ concentrations for an enthalpy increase of potential hilling up for the recovery of higher enthalpy with dissipative entropy out of the system. Thus, a kinetic of multiplicative association by synchronizing photon emission allows a common signaling for multi-neuronal functional coherence. This reinforcement is required for operating a near null noise, to avoid chaotic asynchrony. The effect involves nano scale of space and time because is mediated by photons moving in a liquid phase: 2.25109m/s (0.75 c). Hence, allowing crosstalk between neurons at a very high velocity, integrating the operative time of systems synchronizing the activity of G-protein-linked receptors in the insulin/glutamatergic and catecholaminergic pathways. The nano space maintains a high rate of molecular collisions, maximizing affinity at saturation values by low concentration of hormones, etc. The structural changes of the transmembrane enzymes coupled to the metabolism of glucose and coupled water cluster H-bond breakdown could reach a high enthalpy to low entropy into the system. Thus, separated structures in nano space could integrate more efficiently their function, maximizing connectivity between neurons and microtubules, for an operative open system inflow of substrate and outflow of products. Hence, the effect of insulin at the tyrosine kinase level would be simultaneously affecting all over the neuronal cytoskeleton of microtubules system and the cell cycle. Thus, overcome the catalytic inanimate thermodynamics for converging from a microscopic reversibility principle to a life itself, adapting at the membrane level a kinetic vectorial order overcoming reversibility. At the cell physiological level NA-AC and insulin receptor tyrosine kinase (IRTK) auto-phosphorylation regulate responsiveness to hormones of ionic concentrations vs chelating metabolites. Thus, a decreased Mg2+produces deactivated AC by releasing free ATP4- and activate IRTK. Thus, allows an integration of the hormonal response of both enzymes by ionic controls. This effect could supersede the metabolic feedback control by energy charge. Accordingly, maximum hormonal response of both enzymes, to high Mg2+ and low free ATP4-, allows a correlation with the known effects of low caloric intake increasing the level of free ions could elevate the average life expectancy.

Mind-Brain Dynamics in the Pathophysiology of Psychiatric Disorders

Article

Jan 2022

Michael Raymond Binder

Brainwave Phase Stability: Predictive Modeling of Irrational Decision

Article

Full-text available

Jun 2022

Zu-Hua Shan

A predictive model applicable in both neurophysiological and decision-making studies is proposed, bridging the gap between psychological/behavioral and neurophysiological studies. Supposing the electromagnetic waves (brainwaves) are carriers of decision-making, and electromagnetic waves with the same frequency, individual amplitude and constant phase triggered by conditions interfere with each other and the resultant intensity determines the probability of the decision. Accordingly, brainwave-interference decision-making model is built mathematically and empirically test with neurophysiological and behavioral data. Event-related potential data confirmed the stability of the phase differences in a given decision context. Behavioral data analysis shows that phase stability exists across categorization-decision, two-stage gambling, and prisoner’s dilemma decisions. Irrational decisions occurring in those experiments are actually rational as their phases could be quantitatively derived from the phases of the riskiest and safest choices. Model fitting result reveals that the root-mean-square deviations between the fitted and actual phases of irrational decisions are less than 10°, and the mean absolute percentage errors of the fitted probabilities are less than 0.06. The proposed model is similar in mathematical form compared with the quantum modeling approach, but endowed with physiological/psychological connection and predictive ability, and promising in the integration of neurophysiological and behavioral research to explore the origin of the decision.

Where’s My Consciousness-Ometer? How to Test for the Presence and Complexity of Consciousness

Article

Full-text available

Mar 2022

Tools and tests for measuring the presence and complexity of consciousness are becoming available, but there is no established theoretical approach for what these tools are measuring. This article examines several categories of tests for making reasonable inferences about the presence and complexity of consciousness (defined as the capacity for phenomenal/subjective experience) and also suggests ways in which different theories of consciousness may be empirically distinguished. We label the various ways to measure consciousness the measurable correlates of consciousness (MCC) and include three subcategories in our taxonomy: (a) neural correlates of consciousness, (b) behavioral correlates of consciousness, and (c) creative correlates of consciousness. Finally, we reflect on how broader philosophical views about the nature of consciousness, such as materialism and panpsychism, may also be informed by the scientific process.

Validating the GCP data hypothesis using internet search data

Article

Aug 2022

Ulf Holmberg

The Global Consciousness Project (GCP) operates under the hypothesis that events that elicit widespread emotion or draw the simultaneous attention of a large number of people could affect the output of hardware-generated random numbers. The hypothesis thus suggests that the mind, in some sense, can interact with matter at a distance, a controversial suggestion because such a mechanism could challenge some current understandings. Testing the validity of the hypothesis thus carries substantial merit as negative results would reinforce already established scientific perceptions, whereas positive results would point in the direction of a needed update. In this paper, it is hypothesized that events inflicting a strong emotional response should also trigger the need for information. As such, global internet search trends should correlate with the GCP data, allowing for the hypothesis to be objectively tested. In practice, Google Trends search data is used to construct several search indexes that are correlated with GCP data aggregates using time series statistics. It is found that the GCP data significantly correlates with the indexes and can be used to improve the statistical model's in-sample fit. Furthermore, it is found that out-of-sample forecasts can be made more accurate if the GCP data is used. The results thus point toward the validity of the GCP data hypothesis and that the data produced by the GCP can be put to practical use by, for example, forecasters.

Mechanisms for Information Signalling in the Universe: The Integral Connectivity of the Fabric of Reality Revealed

Article

Full-text available

Aug 2021

We present a comprehensive concept for the fabric of reality and the creation of life through the generation and integration of information, modelled through toroidal processing of wave energy. We submit that human consciousness cannot be understood in a reductionist context, but that it is rather an expression of a cosmic modality or a universal consciousness. We therefore introduce a mental attribute of the entire cosmos that for our world, requires a wave-like holonomic description, implying non-material physicalism in a cosmopsychism context. It is postulated that the generation of life in the cosmos requires a symmetry breaking from a 4 th spatial dimension (5-D spacetime) involving a Sub-Quantum domain, that contains information conceptualized as a pro-active ontological essence. Thereby, a multi-layered fractal reality is conceived integrated by a universal toroidal/möbius-ring type of connection. This is described at the level of a sub-Planckian scale, and is instrumental in past/future transactional information processing and pilot-wave guiding. In this framework, the Zero-point Energy Field is seen as a transition zone from the Sub-Quantum domain to our quantum world. In concert they provide an all-pervading superfluid quantum field that enables soliton (electron-phonon quasi-particle)-mediated interaction with non-neural brain compartments, in which hydro-ionic (hydronium ions and Ca2+-ions) are instrumental. In this process, freely moving protons form wave-antennas in the water matrices of the brain that can receive active life-information as the building blocks for conscious moments. Toroidal geometry is also involved in the functional organisation of wave-coherence and interference in brain, to assure a personal memory. In addition, we postulate a global memory workspace, associated with, but not reducible to the brain. This field-sensitive holographic workspace, that exhibits an event horizon information projection, is seen to be involved in predictive coding and quality control of awareness and can be conceived as personal double. The imprinting of life conditions in inanimate (pre-biotic) structures in biological evolution is conceived as a toroidal processing of energy-consciousness providing a non-dual recursive creation of reality. The unfolding of pre-mordial information into the future is described in geometric terms and defined in a "Beyond Fibonacci" type of spiral mathematics that also includes an extra 4 th spatial dimension. Recent studies of others indeed have shown that the creation of life can be conceived as a symmetry breaking of condensed bosons from a 5-D informational phase-space, supposedly through formation of magnetic monopoles in a Hicks setting, again using an essential toric information code. The monopoles, produced in this process, interact with DNA/RNA on the basis of the molecular entities of life such as H2O, carbon and nitrogen-bases, and this supports recent work on the role of oscillatory DNA wave resonance in cellular communication, being crucial for problem solving of life cells for survival in their environment. Boson-mediated symmetry breaking, modelled by toroidal spinor geometry was also described in a bifurcative self-interaction model that assumes supervenience of mental on physical states. It is finally concluded that scale invariant information, being expressed on the holographic event horizons of each individual cosmic entity, provides a unified connective principle that reveals an intrinsic mental aspect of the cosmos.

Brodmann’s Localisation in the Cerebral Cortex, The Principles of Comparative Localisation in the Cerebral Cortex Based on Cytoarchitectonics

Article

Jan 2005

K. Brodmann

Cytoarchitecture of the human cerebral cortex: MR microscopy of excised specimens at 9.4 Tesla

Conference Paper

Sep 2002

BACKGROUND AND PURPOSE. The laminar patterns displayed by MR microscopy (MRM) form one basis for the classification of the cytoarchitectonic areas (Brodmann areas). It is plausible that in the future MRM may depict Brodmann areas directly, and not only by inference from gross anatomic location. Our purpose was to depict the laminar cytoarchitecture of excised, formalin-fixed specimens of human cerebral cortex by use of 9.4-T MR and to correlate MR images with histologic stains of the same sections. METHODS: Formalin-fixed samples of human sensory isocortex (calcarine, Heschl's, and somatosensory cortices), motor isocortex (hand motor area of M1), polar isocortex (frontal pole), allocortex (hippocampal formation), and transitional periallocortex (retrosplenial cortex) were studied by MRM at, 9.4 T with intermediate-weighted pulse sequences for a total overnight acquisition time of 14 hours 17 minutes for each specimen. The same samples were then histologically analyzed to confirm the MR identification of the cortical layers. Curves representing the change in MR signal intensity across the cortex were generated to display the signal intensity profiles for each type of cortex. RESULTS: High-field-strength MR imaging at a spatial resolution of 78 X 78 X 500 mum resolves the horizontal lamination of isocortex, allocortex, and periallocortex and displays specific intracortical structures such as the external band of Baillarger. The signal intensity profiles demonstrate the greatest hypointensity at the sites of maximum myelin concentration and maximum cell density and show gradations of signal intensity inversely proportional to varying cell density. CONCLUSION: MRM at 9.4 T depicts important aspects of the cytoarchitecture of normal formalin-fixed human cortex.

No awareness of neural activity in primary visual cortex

Article

Jan 1995

Christof Koch

Modality and topographic properties of single neurons of cat's somatic sensory cortex

Article

Jan 1964

V. Mountcastle

The "mental" and the "physical"

Article

Jan 1958

H. Feigl

Measuring the thickness of the human cerebral cortex using magnetic resonance images

Article

Jan 2000

The columnar organization of the neocortex

Article

Apr 1997

V B Mountcastle

The modular organization of nervous systems is a widely documented principle of design for both vertebrate and invertebrate brains of which the columnar organization of the neocortex is an example. The classical cytoarchitectural areas of the neocortex are composed of smaller units, local neural circuits repeated iteratively within each area. Modules may vary in cell type and number, in internal and external connectivity, and in mode of neuronal processing between different large entities; within any single large entity they have a basic similarity of internal design and operation. Modules are most commonly grouped into entities by sets of dominating external connections. This unifying factor is most obvious for the heterotypical sensory and motor areas of the neocortex. Columnar defining factors in homotypical areas are generated, in part, within the cortex itself. The set of all modules composing such an entity may be fractionated into different modular subsets by different extrinsic connections. Linkages between them and subsets in other large entities form distributed systems. The neighborhood relations between connected subsets of modules in different entities result in nested distributed systems that serve distributed functions. A cortical area defined in classical cytoarchitectural terms may belong to more than one and sometimes to several distributed systems. Columns in cytoarchitectural areas located at some distance from one another, but with some common properties, may be linked by long-range, intracortical connections.

Neuronal assemblies: necessity, signature and detectability

Article

Oct 1997

The ease with which highly developed brains can generate representations of a virtually unlimited diversity of perceptual objects indicates that they have developed very efficient mechanisms to analyse and represent relations among incoming signals. Here, we propose that two complementary strategies are applied to cope with these combinatorial problems. First, elementary relations are represented by the tuned responses of individual neurons that acquire their specific response properties (feature selectivity) through appropriate convergence of input connections in hierarchically structured feed-forward architectures. Second, complex relations that cannot be represented economically by the responses of individual neurons are represented by assemblies of cells that are generated by dynamic association of individual, featureselective cells. The signature identifying the responses of an assembly as components of a coherent code is thought to be the synchronicity of the respective discharges. The compatibility of this hypothesis is examined in the context of recent data on the dynamics of synchronization phenomena, the dependence of synchronization on central states and the relations between the synchronization behaviour of neurons and perception.

Cortical areas in visual awareness [7]

Article

Jan 1995
NATURE

The Cerebellum As a Neuronal Machine

Book

Jan 1967

The Electromagnetic Field Theory of Consciousness A Testable Hypothesis about the Characteristics of Conscious as Opposed to Non-conscious Fields

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