## 4 The Electromagnetic Field Theory of Consciousness
### Proposed Characteristics of Conscious EM Fields  
**4.1.1** First, it is clear that in order to be conscious, a field has to be stronger than a certain basic minimum. Evidence supporting this claim includes a report of binocular rivalry studies using MEG [83], which to quote the authors shows that  
\"1. Neural responses to rivalrous visual stimuli occurred in a large number of cortical regions, both when the subject consciously perceived the stimuli and when he did not.  
2. Responses evoked by a stimulus over a large portion of the scalp were stronger when the subjects were conscious of it than when they were not.\"  
On the basis of a comparison of the analytic power of waking and unconscious ECoG data measured at a series of wavelengths and bandwidths, [PERSON] and colleagues [84] estimate that the minimum analytic power necessary for consciousness is of the order of 50 \(\upmu\)V\({}^{2}\)/Hz over the frequency range 1-100 Hz.  
**4.1.2** However, simple power is clearly not enough. Dreamless sleep involves huge EEG slow waves and no consciousness at all. Also, not every evoked potential results in consciousness. For example, respectably sized ECoG evoked potentials can be recorded from visual cortex in response to auditory stimuli that did not evoke any visual experience at all [85]. (To return to the material in Section 2.2, these unconscious evoked potentials recorded over the visual cortex may well represent the physical instantiation of focal attention. If a sound is heard as originating from a particular location in space, it is advantageous in evolutionary terms to boost the likelihood that any visual event in the same location will be noticed, so the audiovisual pathway is activated and the relevant area of visual space automatically and unconsciously primed. Hence, attention is an unconscious process that serves to enable consciousness, but is not identical with it).  
So in order to be conscious, brain-generated EM patterns not only have to be strong enough: they also have to be spatially patterned in some way. One speculation is that the pattern distinguishing conscious from unconscious fields may be as shown in Figure 2. Initial tests suggest that this speculation may be partly right, but further tests are obviously needed.  
**4.1.3** It is suggested that different modalities of conscious experience are also differentiated by spatial patterning of LFP fields in the radial direction [70]. The rationale here is that it has been known for over a century that differences in the relative thickness of the various layers of neocortex is diagnostic of areas that are devoted to particular sensory modalities. Thus, it seems reasonable to expect that radial patterns of LFPs may differ depending on the area of cortex that generates them, which, in turn, depends on the sensory modality. Again, the testing of this speculation would be relatively straightforward technically.  
**4.1.4** Spatial patterning of putatively conscious fields in the tangential direction (resulting from differences between the activity of adjacent anatomical columns) has been shown in animal experiments to define different experiences within a given sensory modality [86; 87; 88; 89].