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A blog written for those whose interests more or less match mine.

Consciousness in the electric brain: Currents? or Field?

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I came across “Brain wifi,” with the subtitle:

Instead of a code encrypted in the wiring of our neurons, could consciousness reside in the brain’s electromagnetic field?

The article, by Johnjoe McFadden, professor of molecular genetics at the University of Surrey, begins:

Some 2,700 years ago in the ancient city of Sam’al, in what is now modern Turkey, an elderly servant of the king sits in a corner of his house and contemplates the nature of his soul. His name is Katumuwa. He stares at a basalt stele made for him, featuring his own graven portrait together with an inscription in ancient Aramaic. It instructs his family, when he dies, to celebrate ‘a feast at this chamber: a bull for Hadad harpatalli and a ram for Nik-arawas of the hunters and a ram for Shamash, and a ram for Hadad of the vineyards, and a ram for Kubaba, and a ram for my soul that is in this stele.’ Katumuwa believed that he had built a durable stone receptacle for his soul after death. This stele might be one of the earliest written records of dualism: the belief that our conscious mind is located in an immaterial soul or spirit, distinct from the matter of the body.

The Katamuwa Stele cast, digitally rendered by Travis Saul. Courtesy of the Oriental Institute of the University of Chicago.

More than 2 millennia later, I was also contemplating the nature of the soul, as my son lay propped up on a hospital gurney. He was undertaking an electroencephalogram (EEG), a test that detects electrical activity in the brain, for a condition that fortunately turned out to be benign. As I watched the irregular wavy lines march across the screen, with spikes provoked by his perceptions of events such as the banging of a door, I wondered at the nature of the consciousness that generated those signals.

Just how do the atoms and molecules that make up the neurons in our brain – not so different to the bits of matter in Katumwa’s inert stele or the steel barriers on my son’s hospital bed – manage to generate human awareness and the power of thought? In answering that longstanding question, most neurobiologists today would point to the information-processing performed by brain neurons. For both Katumuwa and my son, this would begin as soon as light and sound reached their eyes and ears, stimulating their neurons to fire in response to different aspects of their environment. For Katumuwa, perhaps, this might have been the pinecone or comb that his likeness was holding on the stele; for my son, the beeps from the machine or the movement of the clock on the wall.

Each ‘firing’ event involves the movement of electrically charged atoms called ions in and out of the neurons. That movement triggers a kind of chain reaction that travels from one nerve cell to another via logical rules, roughly analogous to the AND, OR and NOT Boolean operations performed by today’s computer gates, in order to generate outputs such as speech. So, within milliseconds of him glancing at his stele, the firing rate of millions of neurons in Katumuwa’s brain correlated with thousands of visual features of the stele and its context in the room. In this sense of correlating with, those brain neurons would supposedly know at least some aspects of Katumuwa’s stele.

Yet information-processing clearly isn’t sufficient for conscious knowing. Computers process lots of information yet have not exhibited the slightest spark of consciousness. Several decades ago, in an essay exploring the phenomenology of consciousness, the philosopher Thomas Nagel asked us to imagine what it’s like to be a bat. This feature of being-like-something, of having a perspective on the world, captures something about what it means to be a truly conscious ‘knower’. In that hospital room watching my son’s EEG, I wondered what it was like to be one of his neurons, processing the information registering the slamming of a door. As far as we can tell, an individual neuron knows just one thing – its firing rate. It fires or doesn’t fire based on its inputs, so the information it carries is pretty much equivalent to the zero or one of binary computer language. It thereby encodes just a single bit of information. The value of that bit, whether a zero or a one, might correlate with the slamming of a door, but it says nothing about the door’s shape, its colour, its use as a portal between rooms or the noise of its slamming – all features that I’m sure were part of my son’s conscious experience. I concluded that being a single neuron in my son’s brain would not feel like anything.

Of course, you could argue, as neurobiologists usually do, that . . .

Continue reading. There’s much more.

Then in the New Yorker I was reading “Do Brain Implants Change Your Identity?” by Christine Kenneally. It’s an interesting article, but what caught my eye was a description of the conscious experience of an epilectic seizure, which is (as the article explains) an electric storm in the brain which of course would disrupt the electromagnetic field. If that indeed is where consciousness resides, that would explain this woman’s description:

. . . The human brain is a small electrical device of super-galactic complexity. It contains an estimated hundred billion neurons, with many more links between them than there are stars in the Milky Way. Each neuron works by passing an electrical charge along its length, causing neurotransmitters to leap to the next neuron, which ignites in turn, usually in concert with many thousands of others. Somehow, human intelligence emerges from this constant, thrilling choreography. How it happens remains an almost total mystery, but it has become clear that neural technologies will be able to synch with the brain only if they learn the steps of this dance. . .

. . . I asked Leggett to describe what it was like to have a seizure. She didn’t know. When one took hold, she was ripped out of her consciousness; she wasn’t there. Afterward, there was a terrible sense of having been absent. She would feel mortified in front of anyone who had witnessed the seizure and alarmed as she took stock of the injuries that she often suffered. Even worse, she said, was that epilepsy stole her memories. Every time she had a seizure and then returned, she seemed to have left some of her memories behind her. . .

Written by Leisureguy

19 April 2021 at 5:42 pm

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