Christof Koch is a neuroscientist distinguished by his rock-solid scientific work and romantic yearning to understand consciousness. He recently closed an essay by wondering: “What is it about the brain, the most complex piece of active matter in the known universe, that turns its activity into the feeling of life itself?” No coincidence with that phrasing—The Feeling of Life Itself is his latest book. He argues that consciousness is produced by the brain but that it’s also more widespread in nature than we might suppose.
His essay described new experimental work, from Stanford neuroscientist Kieran Fox and his colleagues, that explored the effects of electrically stimulating the brain, which revealed an ordering principle. That is, the more removed from sensory input or motor output structures a brain region is, the less likely it is that it contributes to our subjective experience. The “exacting data,” Koch wrote, “provides critical causal, not just observational, evidence to identify the neuronal correlates of consciousness.”
Neuronal correlates of consciousness are the parts of the brain thought to be required for consciousness to occur. The idea that there are only neuronal correlates of consciousness, and that these correlates are the patterns of synaptic firing in specific parts of the brain, is what you might call the conventional view in neuroscience. If we peer deeply into the brain, in other words, what we’ll find is that electrochemical synapse firings—produced by neurons of various types—are responsible for, as Koch puts it, the feeling of life itself, consciousness.
“It was a jaw-dropping moment, for us and for every scientist we told about this so far.”
But what if there’s more to the story? What if the electromagnetic fields generated by, but which are not identical to, the neuroanatomy of the brain, are in fact the primary seat of consciousness? The brain’s fields are generated by various physiological processes in the brain, but primarily by trans-membrane currents moving through neurons.
These fields are always oscillating and they come in various speeds, clustered around certain bands, from delta on the lower end at 1-2.5 cycles (oscillations) per second (Hertz) up to gamma at 40-120 cycles per second.
Some neuroscientists have long considered the brain’s oscillating electromagnetic fields to be interesting but merely “epiphenomenal” features of the brain—like a train whistle on a steam-powered locomotive. Electromagnetic fields may just be noise that doesn’t affect the workings of the brain. Koch still seems to lean this way.
“While at this early stage of the exploration of the brain it would be foolish to categorically rule out any physical process,” he told me, “as an electrophysiologist I’m less enthused about ascribing specific functions to specific frequency bands, let alone experience. The causal actors between neurons that act at the time scale relevant for consciousness (5-500 milliseconds) are action potentials that cause, in turn, synaptic release of packets of neurotransmitters.”
He thinks the extent to which oscillations affect neuronal firing patterns remains an open question. “Consider the sounds the beating heart makes,” he said. “These can be picked up by a stethoscope and can be used to diagnose cardiac conditions. However, there is no evidence that the body exploits these sounds for any function.”
I asked Wolfgang Klimesch, a professor at the University of Salzburg, what he thought about Koch’s view on electromagnetic fields. Klimesch developed the “binary hierarchy brain-body oscillation theory,” which says that consciousness is a function of various levels of resonance both within the brain and between the brain and various other organs, like the heart and stomach.