## 4 The Electromagnetic Field Theory of Consciousness
### A Manifesto for Future Experimental Testing of the EM Field Theory of Consciousness  
2.1 In order to measure the spatial patterns that are proposed above as constituting consciousness, physics dictates that it is necessary to record from microelectrodes that are positioned less than a mm from the synapses producing any given section of the pattern [72]. In practice, this means recording directly from the neocortex of waking subjects, using 3-dimensional arrays of electrodes consisting of a large number of multi-contact shanks that are arranged in a closely spaced grid. In recent years, both suitable electrodes and the ability to record from hundreds of contacts simultaneously have become commercially available, so the time is ripe technically for investigation of the proposals in Section 4.1. The question of whether animals or human neurosurgical patients should be the subjects of such recordings is moot. Animal subjects in some ways provide easier access, but their inability to report verbally on their conscious experiences is a significant problem that probably outweighs this advantage. 2.2 Every scientific theory worth its salt should be falsifiable. One critical experimental test of the idea that conscious experiences are EM patterns was suggested five years ago [70], but repeated attempts by the author to find a venue in which to carry out the experiment have so far proved unsuccessful. This test involves clamping or zeroing out putatively conscious EM fields using an extracellular version of the classic voltage clamp technique [90,91]. To fit in with modern standard of care practice in epilepsy clinics (where electrodes are sometimes implanted for the clinical purpose of localising both epileptic foci and eloquent cortex prior to excising the first and sparing the second, in order to produce an acceptable cure for the patient's epilepsy), the clamp would best be implemented in software rather than hardware. The basic aim would be to inject into the extracellular fluid, at a spot predicted by the theory to underpin the simplest possible experimentally inducible experience (for example the sound of a click), sufficient current to just prevent the change of voltage that would normally constitute the local field potential evoked by the auditory stimulus. If this clamp is implemented successfully, it should be possible to compare the current injected by the clamp with the LFP produced by the stimulus in the absence of the clamp, to prove that the clamp does not affect ongoing synaptic activity. If it does not, the current waveform will be a perfect inverse copy of what would normally be the LFP. To complete the experiment, the patient is then simply asked whether or not they heard a click. If they always hear a click with this particular auditory stimulus in the absence of a clamp, but reliably fail to hear one in the presence of the clamp, the only thing that will have been altered by the clamp is the EM field. The current measurement mentioned above will have ensured than synaptic activity _per se_--the release of neurotransmitter from the presynaptic terminal, interaction of transmitter with postsynaptic receptors, consequent inflow of ions from the extracellular fluid into the postsynaptic dendrite (potentially leaving a transient 'hole' in the extracellular fluid, which hole has here been filled by the injected current)--all continued as normal. So the EM pattern _and only the EM pattern_ has been removed. The crucial difference between this experiment and the sledgehammer ablation of synaptic activity by a blast of TMS delivered to the scalp, or directly injected current of the sort routinely used clinically to locate eloquent cortex, is the intensity of the current injection. Too much and you stop synapses from working altogether, by depolarising them (this is the desideratum during clinical work to localise eloquent cortex, for example). Too little current injection and you still see an LFP.